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Zilch
05-26-2005, 12:28 AM
Continued from Quick & Dirty 4430-Inspired Two-Ways Part I (http://audioheritage.org/vbulletin/showthread.php?t=9745)

Giskard:

1) 1.7 uF, 0.6 mH
2) 2.15 uF, 0.6 mH
3) Full Range

Boosted everything about 3 dB, no frequency shift. (SOUNDS good tho....)

I assumed you meant stay with original inductor value, not Guido's suggested 1.0 mH?

4313B
05-26-2005, 05:09 AM
Boosted everything about 3 dB, no frequency shift. (SOUNDS good tho....)Ok... should have been ~ 1.7 dB but whatever. How are you on coil values? Can you go in increments of 1/100 mH? With the 2.15 uF you have change the inductor to 0.76 mH. That should give you a 4 dB increase at 1 kHz and a 2 dB increase overall in the high pass.

Zilch
05-26-2005, 10:42 AM
How are you on coil values? Can you go in increments of 1/100 mH? I have four Jantzen 20 Ga 1.0 mH coils, and a B&K LCR meter that reads to 0.01 mH, yes. WT2 confirms the readings are correct, as required.

I'll unwind one to 0.76 mH and try it. I can also crank the RTA resolution up to 2.5 dB per major division, now that we're close. Can you illustrate graphically what's going on with this portion of the circuit for us please? I'm surprised the values require this level of precision.

I should invest in a filter simulator myself, probably. One thing this thread has made abundantly clear to me is that it's about the crossovers as much as the drivers, and, surprisingly, within fairly broad limits, the boxes themselves are the least of getting it all to work together....

4313B
05-26-2005, 11:54 AM
Yeah, I can post what's going on with the voltage drive in awhile. Let me know how the 0.76 mH works first. Post the bb6p file for the horn/cd combo complete with Q, fs, etc. I'll also need an impedance curve from 500 Hz on up.

"One thing this thread has made abundantly clear to me is that it's about the crossovers as much as the drivers"

We've talked about this at length before. Back in the day when JBL was cranking out such stellar circuits as the N100, other companies were taking junk drivers and making them sound listenable with proper application of filter design theory.

Zilch
05-26-2005, 01:35 PM
Bigger than a breadbox, but decidedly smaller than L200 (rear baffles aligned here), Z1 has good WAF potential; no matter the viewing angle, you can never see all of the sides at once, thus masking its real volume. Trompe l'oeil confers delicious asymmetry (think L250,) in all but direct head-on view.

In comparison to real 4430, note that it's the same width (22") and 1" deeper at the base (ignoring 4430 horn, which sticks out an additional 3-1/4"). No matter, the difference in perceived mass is apparent.

O.K., standing-wave and reflections gurus, does this design really (or theoretically, even) SUCK?

[Excuse the clutter, please. I DO have a life here.... :p ]

johnaec
05-26-2005, 02:01 PM
My personal preference would be to follow the front trapezoidal shape all the way front to back... :)

John

Zilch
05-26-2005, 06:00 PM
Giskard:

0) 2.15 uF, 0.60 mH
1) 2.15 uF, 0.76 mH
2) Full range

Guido
05-27-2005, 03:49 AM
Sorry for late cooperation!
I was on a business trip.

Hope Giskard don't mind if I jump in with the voltage drives.

Green: original
Yellow: My suggestion 1.5uF, 0.8mH
Pink: My suggestion 1.0uF, 1.0mH
light blue: Giskards suggestion 2.1uF, 0.6mH
dark blue: Giskards suggestion 2.1uF, 0.76mH

We're coming closer ;) Slowly:(

Guido
05-27-2005, 03:55 AM
Green: original

Yellow: 2,15uF, 1,0mH

4313B
05-27-2005, 12:30 PM
Hope Giskard don't mind if I jump in with the voltage drives.
That isn't what I get. You must be using a different load. I never got the impedance curve from Zilch so I just used 8 ohms. My suggestion was based on 8 ohms and the Q was kept identical to the original, again, based on 8 ohms. You guys figure it out from here.

Input adjusted for gain to show actual curves.

Zilch
05-27-2005, 02:08 PM
The RTA curves are on my best driver mounted in L200, which I'm pulling today for Widget's testing tomorrow, so I'll be able to get the complete WT2 measurements completed and posted this evening. I'm wanting to keep the variables of different drivers out of it for now, though I may measure and report at least two. We'll have CLIO results as a cross-check on WT2 in a few days, looks like. :)

From those curves, it seems the entire correction is less than 15 dB. It is very encouraging that we're not having to push these as hard as earlier designs to get the requisite HF boost....

Zilch
05-27-2005, 11:20 PM
Giskard:

BBP and WOO files as requested. The impedance sweeps are in the .woo files, presumably, Arb1, 40 pts. If you need higher resolution or want them in ASCII log files, let me know.

XLe (1 kHz) is 5.9740 on #1, 6.2528 on #2

Note: The second filter in the circuit was changed early on in conformity with actual factory crossovers received:

C2 = 6.0 uF (not changed)
R1= 2.5 Ohms
L4= 0.04 mH, .225 Ohms

Guido
05-28-2005, 03:22 AM
That isn't what I get. You must be using a different load. I never got the impedance curve from Zilch so I just used 8 ohms. My suggestion was based on 8 ohms and the Q was kept identical to the original, again, based on 8 ohms. You guys figure it out from here.

Input adjusted for gain to show actual curves.

Giskard, I used the real values given from Zilch.

2.5 Ohm for R1
0.04 mH for L4

The load I used was 8 Ohms

I think this is the reason for the other results.

Mr. Widget
05-29-2005, 02:34 AM
Here is the Clio impedance curve from one of Zilch's LE14H-3s. The red curve is with the woofer on a carpet covered concrete floor sitting on blocks to avoid blocking the vent. The Blue curve is in free air. The Zipped data file is from the Blue curve.

Widget

Zilch
05-29-2005, 11:12 AM
Mr. Widget's latest horn/driver studies for this project are now posted here:

http://audioheritage.org/vbulletin/showthread.php?t=6050

rloggie
05-30-2005, 04:49 PM
Having heard the "work in progress" today, I would say they sounded wonderful.
Lots of high frequency "sparkle" and the famous JBL dynamics. I sincerly doubt the addition of any tweeter, super or otherwise, would add to the enjoyment of the upper end. Thanks Zilch. I'd love an invite when YOU think the design is finished.:applaud:

Zilch
05-30-2005, 06:09 PM
Hmmmmm.... :hmm:

Figge
05-30-2005, 06:39 PM
oh no....:scold:

WTPRO
05-31-2005, 09:24 AM
Hi all

FYI, if you export an ASCII file from the WT2 and have a look you will find that the terminal impedance (the actual crossover load) has been split into real (resistive) and imaginary (inductive) components. Using this in your circuit simulator should give you results that are very accurate.

The next WT2 software release will of course have the same stuff as the original, but also include some frequency dependent R's and L's to better match the Z curve.

Note: The 'results' pulldown has a sub menu for copying Q/Fs, Vas or Box sweeps to an arbitrary buffer. After copying to the arbitrary buffer, you can then view that data in the arbitrary format inside the results window, and that includes the R/I split out.

Best regards
WTPRO

Mr. Widget
05-31-2005, 09:36 AM
Hey Zilch,

Have you made a comparison between the WT2 and Clio on that LE14H-3?

Widget

Zilch
06-08-2005, 12:31 AM
Have you made a comparison between the WT2 and Clio on that LE14H-3?Not yet, alas. Too much data, too little time. :(

I'll get to it tho. I promise! :)


My suggestion was based on 8 ohms and the Q was kept identical to the original, again, based on 8 ohms. You guys figure it out from here.Assuming 8 Ohms impedance, the Q is 0.425. I don't know why JBL's calling that a 1.1 kHz crossover frequency, 'cause it's down 10 dB there. 2.15 uF with 0.76 mH shoulda done it, at least at that frequency.

I was expecting the entire knee to shift leftward, but constant Q seems to be the right approach, as the response is nowhere near flat in that region. Part of what it's doing is attenuating a 5 dB peak there. Am I starting to get this?

What tool(s) do I need to get on the same page and raise my level of incompetency here?

[Guido should be gettin' his drivers soon....]

Zilch
06-10-2005, 01:29 AM
Kinda 60's moderne esthetic:

johnaec
06-10-2005, 06:42 AM
Kinda 60's moderne esthetic:I think a walnut finish would look better...:duck:

John

Zilch
06-10-2005, 10:26 AM
Piano black with radiused corners, maybe? :D

Them black lacquer L150's are sure pretty.

Them redn's too.

Gonna need a BIG press to mould them sides. :p

[Workin' on it.]

Think I'll make a pair with 2235's, too. Shane's busted E140's are here, recone kits on order.

Jus' need an adventurous cabineteer, now.... :barf:

Zilch
06-19-2005, 11:59 AM
Secured in a late-night run to Sunnyvale yesterday, second Citation 7.4 purchased for me by JuniorJBL (he wanted the driver, I wanted the box,) was picked up and delivered upstate by Ti Dome. Many thanks to these generous forum members!

Here, they're loaded with new butyl-surround LE14H-3 for testing in combination with 2431H and PT-F waveguides. So far, so good. We're breakin' 'em in today. :p

Johnaec's comin' over later to listen to the several iterations of "Q&D" here. L200 cab version visible behind these....

These two Citations, both made in 1995 from the date codes on the stealth filters in them (see above), have different depths. The newer one (left) is 1.25" deeper (16.75" vs 15.5"), and made from thicker material, apparently (1" vs. 3/4"?), with less internal bracing. Didn't notice until AFTER I'd loaded them woofers, of course.

Port on older one (right) is unflared, as described earlier by Giskard. Straight pipe, 4" dia., 8" deep.

Design subject to change without notice, apparently. Guessin' it was cheaper to make them thicker than to keep strugglin' with compound cross-bracing inside.

[Yeah, O.K., I'll clean up the fingermarks there RIGHT now.... :p ]

johnaec
06-19-2005, 07:28 PM
OK - I was able to make it over to Zilch's today to pick up some speakers he'd picked up that Titanium Dome had graciously brought up from Anaheim for me, (thanks, Dome!).

I was finally able to listen to a couple iterations of the various designs Zilch has been working on. These were also compared with Zilch's stock 4430's, though those were in a different listening room. We used the same source material for all tests so relative comparisons were easier.

The sets made up of the LE14H-3's, 2431H's and PT-F waveguides were pretty surprising. Both the LF and HF were better than I would have expected, especially with such a flat little horn. I understand the LF was just using natural roll-off at the high end, while the crossover design for the HF duplicates JBL's design from their pro-series speakers using this HF combination. This resulted in exceptionally flat response all the way out to 20K, as noted in an earlier message. This HF combination was also used in Zilch's L200's. In both these cases, there was noticeably extended HF response compared to the two systems we listened to with the 2344 horns. Dispersion does narrow noticeably in the last half-octave with the PT-F horns, but the extended response is definitely there. The L200 version did exhibit deeper bass with the 2235's than the LE14H-3, but much of this was likely because they were sitting on the floor, and much closer to the wall. The LE14H-3 did seem to feel "tighter" in the low end, though - I actually preferred these over the 2235's.

As mentioned, we also listened to the "quick and dirty" set, made up of B380 cabinets with the 2344's sitting on top, and also Zilch's stock 4430's . As expected, these pretty much matched the sound of each other, with the exception that the stock versions produced noticeably stronger bass, but again, this was likely because the stock ones were on the floor and against a wall.

Dispersion of both HF systems, (2344 and PT-F), was very good, although the 2344's seemed to be a little more "spacious" than the PT-F, though the extended HF response of the 2431H's with the PT-F was better. What I think is happening here is that the PT-F's seem more "point-source" because the driver throat is completely open in the PT-F, which means you're getting a direct shot at the source, unlike the 2344, which squeezes down before the flare. This makes the sound from the PT-F's easier to pinpoint, as compared to a more nebulous source with the 2344's, though the difference is relatively minor. It's the extended HF response of the 2431H which is most noticeable.

The big thing I took from all of this is how closely the general sound of all four systems sounded, the logical conclusion given the similar RTA response. When running with such flat curves, many would tend to consider this a somewhat "dry" sound, but being flat is definitely a better place to start from compared to many high-end speakers that get rave reviews for what I consider "colored" sound, usually in a form of loudness compensation being built into the response. While the average user may prefer this "colored" sound, it's far better to start with flat response and tailor the sound yourself, rather than having the speaker sound "tailored" by the manufacturer. The flat frequency response of JBL's is one of the main reasons for their stature - you're getting accurate reproduction to start with instead of "colored" or "tailored" sound. Zilch's versions prove this isn't a fluke!

I also got to see the mock-up of Zilch's "trapezoid" design. It really looks much better in person than the pics, at least as far as volume/mass goes. I think these finished in nice veneer will be quite attractive! And the combination of LE14's and the 2431H/PT-F is a very attractive proposition! Simple, inexpensive 2-ways with exceptionally flat response, and without all the complexity of getting 3 or 4 way components all operating together.

Anyway, it was a lot of fun. We're lucky to have someone like Zilch here, to actually produce the crossover/driver variations to really conclusively nail down how all the combinations sound and compare. And someone looking to put together a straightforward, good sounding 2-way system should really take advantage of the groundwork Zilch has laid down!

Thanks, Zilch!

PS - 'also wanted to mention how great the L200 foam grilles from Sonofagun looked - another great resource!

John

Guido
06-20-2005, 03:16 AM
Zilch,

how do you damp the 2431H? L-Pad? And if so where did you install it "in" the AM Network topology?

Another Point: Did you ever try the 2431H on the 2344 Horn. Maybe with reversing the Adaptor you sent me? Could be a nice combo. What do you think?

Guido
06-20-2005, 03:23 AM
Assuming 8 Ohms impedance, the Q is 0.425. I don't know why JBL's calling that a 1.1 kHz crossover frequency, 'cause it's down 10 dB there. 2.15 uF with 0.76 mH shoulda done it, at least at that frequency.

I was expecting the entire knee to shift leftward, but constant Q seems to be the right approach, as the response is nowhere near flat in that region. Part of what it's doing is attenuating a 5 dB peak there. Am I starting to get this?

What tool(s) do I need to get on the same page and raise my level of incompetency here?

[Guido should be gettin' his drivers soon....]

Zilch, I didn't get this. Maybe the language barrier :o:

How exactly can I assist you here?

Zilch
06-20-2005, 09:35 AM
Zilch, how do you damp the 2431H? L-Pad? And if so where did you install it "in" the AM Network topology?That's an issue I haven't addressed yet. I've always run these systems biamped, so I don't know what padding will be required to run HF and LF together. That's another reason we need to get you up and running, so we can compare notes on the optimum approach.

Simplest would be an L-Pad just before the HF driver, assuming it's the HF that needs padding; the impedance varies between about 6.5 and 9 Ohms in the operating range, so any padding will alter the crossover curve. I'll generate new impedance curves on all of the 2431H's here as part of that effort.

As you know, the original padding was done with the crossover component selection itself. How that balances with 2235H and LE14A and H, I haven't yet determined.



Another Point: Did you ever try the 2431H on the 2344 Horn. Maybe with reversing the Adaptor you sent me? Could be a nice combo. What do you think?Nope, never tried that. Once I found a viable alternative to NLA 2344(A), I ran with that. Sounds like something you might try, tho, since you have all of the parts (soon). :)

PT-F is physically easier to integrate into various system designs. While 2344A will "fit" into L200, for example, and even be concealed by the grille, the deep overhang at the top could easily create reflections. Also, it's obvious that my own Z1 cabinet design would have to be 6" taller to accommodate PT-H or 2344A. Thus, I abandoned the larger square horns in favor of the compact format early on.

While the pattern control of the compact PT-F is not as precise, perhaps, the white paper states that its distortion is lower. They measure and sound the same to me, but Johnaec hears a difference in directivity in the last half-octave. We'll likely follow up with polar response tests on these....



Zilch, I didn't get this. Maybe the language barrier :o:

How exactly can I assist you here?Mr. Widget has CLIO FR curves on the three different crossover component combinations we have tried, which he'll likely post here soon. You'll see the results of the tweaks we've tried so far at higher resolution than I can achieve with simple 1/3 octave RTA.

Given that we have FR and impedance curves for the drivers on PT waveguides, my question is, "What software tools do I need to design and sim the crossover we're using?"

You and Giskard seem to be using similar (if not the same) tools. What do I need to purchase to get onto the same page? Xover 3 Pro?

Guido
06-20-2005, 01:51 PM
Giskard use "PSpice"

I use "Circuit Maker". Not so comfortable but work well enough.

Check your email! Hope you can handle 3.5 Mb??

Mr. Widget
06-22-2005, 11:43 PM
Mr. Widget has CLIO FR curves on the three different crossover component combinations we have tried, which he'll likely post here soon. You'll see the results of the tweaks we've tried so far at higher resolution than I can achieve with simple 1/3 octave RTA.

Sorry about the delay. Here is the plot of the three networks.

Widget

Zilch
06-22-2005, 11:57 PM
And here's the filter sims and driver/horn response curves. Looks like we've got some control here. :D

Two peaks to tame. One of them's kinda random, tho.

We've certainly got the HF extension we hear and see on RTA. Maybe a little too much, even.

Just need impedance curve now. Gonna be a statistical exercise, n=6....


Edit: What's going on here?

Top graph shows computer simulations of the "AM" high frequency crossover design we're using with 2431H drivers on Progressive Transition (PT) waveguides. Three versions are shown, reflecting minor circuit "tweaks" (discussed earlier here) to lower the high pass frequency slightly for more seamless mating with low frequency driver (2235 or LE14) response as filtered by the orange curve at the left there.

Second graph is actual measured frequency responses of 4 different 2431H drivers mounted on PT-F (compact) waveguides.

Bottom curves are the results just posted by Mr. Widget, the three crossover tweaks as they are reflected in actual performance on 2431H #1 (red curve in middle graph). What we've done with the crossovers, as shown in the computer simulations, is apparent also in the actual performance of the driver and horn.

Driver/horn response and crossover filtering combine to provide "precipitous" rolloff below 1 kHz.

Further improvements will likely have to be approached statistically, as there is considerable variability in driver/horn performance in the VHF region, as shown in the second graph. This particular driver/horn exhibits a substantial peak at about 13.5 kHz (what Guido was referring to from the JBL specs?), and runs maybe 2.5 dB too "hot" above that, assuming flat response is the objective....

Zilch
06-23-2005, 01:01 PM
For many, the brain glazes over at the sight of response curves and crossover schematics. Perhaps this little bit more information will help clear the hyper-technical fog over this:

To make the HF driver "play" with the woofer, we could power them each from a separate amp (biamp) and apply the requisite boost in the high frequencies to level out the HF response using active equalization. We'd rather just hook them both to the same amp and have them work right together, tho, and that means use a passive filter crossover network. 4430 does it separately for mid- and high-frequencies; we're doing it "all-in-one" here.

Since passive networks don't add any power to the system, we can't boost anything, only cut. Fortunately, HF compression drivers such as the 2431H we're using here are WAY more efficient than the woofers we're mating them with. 2235H has a sensitivity of 93 dB, for example, and 2431H is up around 110 dB (actual spec unknown).

Thus, we have something like 17 dB of excess SPL available in the HF driver to do the requisite deed when driving both woofer and HF driver from the same amp souirce. All we have to do is progressively attenuate the power delivered to the 2431H from 20 kHz downward to match the SPL of the woofer at the crossover point (1 kHz, in this case). The inverse of the driver response curve above tells us, generally, what the crossover must do to accomplish this, such that the end result is a seemless flat response throughout the range of interest.

The crossover voltage drive curve (top graph) is what we're using to do it. We try to adjust the values of the components in the filter to "shape" the curve (the resultant attenuation varying with frequency) to make the HF driver perform as desired. You can see we have essentially 0 dB attenuation at 20 kHz, there. Response at all frequencies below that is cut by varying degrees, as required, to yield flat output.

The result is shown in the combined response curve (bottom graph), where we measured the actual performance of crossover, driver, and horn playing together. Looking at the various curves, we only use up ~13.5 to 15 dB of the available 17 dB HF driver "headroom" to do it here. That's a good thing; if much more were required, we'd run out of SPL and end up giving up response somewhere.

Well, that's the "Quick and Dirty" synthesis of what's going on with this: Graph A + Graph B = Graph C = sounds GOOD!! Hope that helps. :)

Zilch
06-23-2005, 01:54 PM
http://audioheritage.org/vbulletin/showthread.php?p=60915#post60915

Guido
06-23-2005, 01:54 PM
Well explained! It's good for our not THAT experienced members. :applaud:

Zilch
06-25-2005, 03:26 PM
It's good for our not THAT experienced members. :applaud:Yeah, that'd be ME!

It's only my second pass down this path.... ;)


Infredible was just here with his stack of astounding test disks puttin' the Q&D's through their paces. I'm pleased to report that no apparent damage occurred to the either the house or workshop. Gonna take a day or two for me to decompress.... :p

Guido
06-26-2005, 05:54 AM
Infredible was just here with his stack of astounding test disks .... :p

Which one, which one :bouncy:

Zilch
06-26-2005, 11:03 AM
Peggy Lee, Dave Crusin "Migration" (see thread "What's playing now"), Andreas Vollenweider....

Infredible's complete test kit is proprietary, of course; the ride'll make yer nose bleed. :applaud:

Johnaec brought lotsa Little Feat, others, mostly new to me, expanding horizons here.

Mr. Widget has some good ones I gotta get, too.... :)

It's great fun when forum members bring their favorites to try. You get to hear lotsa different stuff you wouldn't normally hear on your system, and you can turn them on to your own arcane "specialties" at the same time.

Mine? Presently "Red Hot & Blue" Cole Porter compilation, Chico Science (Brazilian), "Amused to Death" (a reminder not to mix politics and rhythm), "Up" (which I don't understand), Brian Ferry "Frantic," and an array of Pink Floyd, of course.

Back to regular programming AFTER this brief musical interlude.... :p

["Soon be oh vah, soon be oh vah...."]

stevem
06-29-2005, 07:44 PM
I too have been playing around a bit with some of the various JBL waveguides, so for what it’s worth, here are some of my first impressions. To provide a frame of reference, my speakers are a three way tri-amped design consisting of a pair of 1401Nd woofers per side in a ported enclosures, a 2012H mid in a sealed enclosure (I plan to try ported soon), and a 2450SL compression driver on a 2332 horn. This horn and driver were designed together, and there is no “transition tube” as found on most JBL HF drivers. The 2450SL is almost identical to the 2451, and similar to the 2450, except this driver does have the transition tube.



My listening room is not very good acoustically. It is 12’ wide by 24’ long, which is an even multiple and not a good thing. There are big built-ins at one end, which shorten the room by about 3’ making it effectively 21’ long. The real killer is the ceiling, which is only 7’2’ high. The walls, floor and ceiling are very rigid, which produces a lot (too much) bass. I have diffusers and bass traps in strategic places, which helps a great deal. The floor is carpeted.



I wanted to try out the PT waveguides because when I read JBL’s technical paper on them, I could see that they are also designed to be used with drivers without transition tubes. I think they even did some of their testing with the 2450SL. Before my current speakers, I was using a DIY 4430 system with the 2344A and 2426H for the HF and a 2235H for the LF. I decided to try the 100x100 degree 12”x12” waveguide first, as that was the same size and dispersion pattern as the 2344A in my prior system. I found the tonal balance of this set up surprisingly similar to the 4430 clone, but with more detail and immediacy. I realized, though, that I preferred the sound of the 2332, probably because it’s pattern is narrower (I think it’s about 90x50 degrees) and doesn’t bounce off the side walls as soon. It also seems to bounce off the ceiling far enough back for the first reflection not to reach the listening position. This pattern gives instruments a warmer and more natural tonal balance. I also didn’t like the 100x100 as much because the highs seemed farther away from the midrange (because it’s larger than the 6”x12” 2332), and the speakers become physically higher. They didn’t sound as coherent from my listing position.



The next waveguide I tried was the 60x40 degree 6”x12” unit. (Zilch had mentioned in an earlier post that the 90x50 degree 6”x12” unit is not available, and he appears to be right. Too bad because this one is probably just right for me). This unit has a similar spectral balance as my 2332 horns, in that it's warm sounding, but they are a bit to “beamy” and up-front sounding for my tastes. The sound character also changes when you stand up, or walk to the back of the room. It’s a very clean and detailed sound, and some of you may like it, but to me it’s a little too much like wearing headphones. By comparison, the 2332 sounds more laid-back, with no beaming at all. I can’t say that the 100x100 unit beamed, but I was more aware of the highs and where they were coming form. This might just have been due to the added distance from the mid. I’m guessing the the more diffuse sound from the 2332 is caused by the diffraction slot used as part of the horn’s design. Non of the PT waveguide use this feature, and this may account for some of their “more direct” character



There is also a 90x50 degree horn in the 12”x12” size, but I’m a little reluctant to try it because of the height issue. I would like to try a 6”x12” version, but as I said, it’s not in production.



For EQ, crossover and delay I use a BSS Omnidrive FDS-266t, which is a great unit. I measure the speaker’s response using an Audio Control SA3050A spectrum analyzer and pink-noise generator. My amps are all Bryston ST series. Of course, the above opinions are purely subjective, and are heavily influenced by my listening room and tastes. As always YMMV.

Mr. Widget
06-29-2005, 08:01 PM
Very interesting info.

My current horns are of a narrower type as well and seem to give a more coherent image. Mine are 80° X 30°. I have no idea if this is why I like them or not. My previous horns which I also really liked were the 2397s which are quite wide in dispersion... they are narrow vertically though... just some ramblings.

Widget

Zilch
06-29-2005, 08:07 PM
With that low a ceiling, the 90° x 50° is likely the better choice. I do have some alternatives coming in with that pattern, but we need to keep after them to make the PT-F version. I'll report on the PT-H as soon as it arrives.

I agree, the 60° x 40° is "beamy." If I had a HT setup, it might be just the ticket.

You might want to try the really cheap 90° x 50° PT waveguide for 1" drivers. It'll screw directly on your 2426H's. Part #338800-001. $9.00 each, IIRC.

Nope, $9.90. :p http://www.jblproservice.com/pdf/Horn%20List/04%20Horn%20Parts%20List%20.pdf

For clarity, you're using 2450SL, not 2431H, correct?

Several other members have commented upon how remarkably similar the PT waveguides and the 2344A here sound....

stevem
06-30-2005, 06:04 AM
Yes, I'm using the 2450SL for the highs. I should also mention that this driver with the 2332 horn takes 10db of boost to flatten it out to 20khz. With the PT waveguides, it seemed to require considerably less boost, and I'm not sure why that should be. Any ideas?

Robh3606
06-30-2005, 07:40 AM
Different horns will require different compensation. I am not familiar with either but from you description in sounds like a wide dispersion CD horn VS. a more tightly controled patern horn. If you look at the biradials in general the wider the patern them more electrical compensation is needed for flat on axis response. Look at a 2344 and a 2370 at two extremes. The 2344 is 100x100 and needs a good amount of compensation to get flat on axis response. Basically the curve for this horn mirrors the compresion driver without a horn. On the 2370 it's 90x40 and the response is much flatter without any compensation in the crossover. Starts rolling off around 7-8k which can be adjusted to increase output in the last octave with the addition of a shunt capacitor say 1uF in the crossover like the L200B crossover.


Rob:)

Zilch
06-30-2005, 12:21 PM
With the PT waveguides, it seemed to require considerably less boost, and I'm not sure why that should be. Any ideas?As Rob says, each horn design requires different compensation. PT's are "hotter" around 8kHz than 2344A, for example, and even within the family, the 60° x 40° more so than the 100° x 100°.

I used AutoEQ on the Behringer UltraCurve with a "stock" PT crossover (from AM6212/00) to get them playing close enough with 2431H to compare sonically....

johnaec
07-02-2005, 05:30 PM
OK - here's a quick 3D version of Zilch's "trapezoid" cabinet. Until I get something better to use I plugged in a 2332 horn, (same size opening as the drawings Zilch gave me), and a 15" LF. I'll try to get some renderings with materials instead of plain colors sometime in the near future.

John

Zilch
07-02-2005, 05:54 PM
Way COOL, John.


That's certainly IT!

First ones I build're gonna get my 15" E140/2235H hybrids in 'em.

[Can't wait now. Nope, nope.... :bouncy:]

johnaec
07-02-2005, 06:17 PM
First ones I build're gonna get my 15" E140/2235H hybrids in 'em.Which horn are you planning on, at least for design purposes? I'll see if I can come up with a 3D version, though if it's got very many complex curves it'll like be simplified for the drawing...

John

Zilch
07-02-2005, 06:29 PM
I'll likely use PT-F 100° x 100°. What you've got there looks like the 60° x 40° version, which is just fine for now. The one we REALLY want is the 90° x 50°, which also looks more like 2332, probably.

You gonna take a stab at the three-way version for over in the 4628B thread?

;)

Edit: John's rendering of the 4628B component version is here:

http://audioheritage.org/vbulletin/showthread.php?p=61675#post61675

johnaec
07-02-2005, 07:21 PM
You gonna take a stab at the three-way version for over in the 4628B thread?Yeah - that one looks real interesting! I'd even conceivably put together a pair sometime, (though I've got a lot of other stuff on the burner first...).

John

Jakob
07-03-2005, 08:35 AM
Hi!

I red with great interest about Your network calculations. What software do you use for this? Is there any way to get the response from a certain driver with a certain horn without measuring?

Thanks: Jakob

Zilch
07-03-2005, 10:02 AM
Hi, Jakob.

I'm using CircuitMaker 6, which is a semi-obsolete schematic capture and circuit simulation program.

For network design, I'm going to try Xover 3 Pro, which is on order.

There are no simulation programs for drivers and horns that I'm aware of. WAY too many variables, I'd imagine.

While it's apparently possible to manage the outcome, actual performance measurement is an essential part of the process, one way or another. Or several ways concurrently, if possible....

stevem
07-07-2005, 08:10 PM
Zilch, since we're talking aboiut PT waveguides, has anyone looked at the AM6200/95? This is a HF and MF module that can go on top of a B380 (or any other woofer) and you can make a quick and dirty 3-way. Is this thing suitable for music in a home listening room? The HF is handled by a 2431H, and the MF uses a horn loaded 2250HPL which looks like an 8 inch variant of the 2012H. Pattern is 90x50, and LF crossover is at about 250hz. Any thoughts?

Zilch
07-07-2005, 09:22 PM
They are mated separately and integrated with various woofers. B380 should work, too.

http://www.jblpro.com/ae/pdf/spec_shts/AM6200_95.pdf

http://www.jblproservice.com/pdf/AE%20Series/AM6200,95-WH.pdf

http://www.jblpro.com/ae/pdf/App_Data_Sht/AM6200_95.pdf

http://www.jblpro.com/ae/am6200_95.html



Actually, this version might be a better choice for home three-way, with 2407 HF:

http://www.jblpro.com/ae/pdf/spec_shts/AM4200_95.pdf

Zilch
07-12-2005, 06:10 PM
Gonna take a bit to figure these out. Right now, I can't tell where anything's coming from. Surely there's an IMAGE in the crossfire there somewhere.

[Sound GOOD, tho.... :p ]

Guido
07-13-2005, 03:21 AM
Omnidirectional;)

Where do you dig out all that stuff ?
Do you have a JBL Mine ?

Zilch
07-13-2005, 01:23 PM
Where do you dig out all that stuff ?
Do you have a JBL Mine ?Those I got on eBay. A pair of 4660's that came out of a church in Modesto, "local pickup only," about 1.5 hour's drive from here.

Interestingly, they are not the "A" version, but have 2425J's in them, anyway. I've pulled them apart for testing for another thread. Gonna replace the 2225H's in them with a pair of 2226H's I have, to free those up for reconing to 2235H.

I installed 2426H's on these 2346 horns to try them as Q&D 4430's, using N3134 and B380, and the results are quite good. This leads to thoughts of installing 2235H's in the 6 cu.ft. 4660's, retuning them if required, and playing them horizontal. We'll see. TOO much fun, these! :bouncy:

I have to read up more of the Everest white paper to understand them better. Alas, the last part of that is missing in the version posted here. Techbot said he intends to get the whole thing posted eventually.

The sound field is VERY wide, of course. Clearly, they've got to be separated more than I've shown them, and you've got to be between them listening. The auditory cues from the woofers, which are handling much of the midrange in this setup, become ambiguous as you move from side to side. Angling them in (the woofers) at 30° as in Everest is important to reestablishing coherency.

Once I get these figured out, I think they'll comprise the final iteration of Quick and Dirty 4430's here (unless something else comes along, of course ;) ), and I'll put together a summary of findings. Word is that this thread will self-destruct at 1000 posts. We don't want THAT to happen.... :p

Zilch
07-16-2005, 12:21 PM
I must say the performance of these 2346 controlled directivity horns is surprising. I've now mated them with "AM" crossovers using 2426H's, and they play flat on axis (perpendicular) out to 20 kHz (see below). Curiously, on driver "reference axis" (30°), the HF is up 5 dB as expected, but not the VHF. Took me a while to discover that; thought one of the drivers mondo wonky for a bit here. Also, gonna have to tweak these crossovers back down to 800 Hz, probably.

Still lookin' good, though; I ain't quibblin' over +/- 2.5 dB at this point, and 20 kHz is up. Ideally, VHF should be boosted at 30° for precedence compensation as accomplished with 2405 in Everest (see Techbot recently updated white paper in Tech Ref forum). JBL could apply their newer Progressive Transition technology to making a more reasonable asymmetrical horn to do all of that, no doubt. Is H2600 the only other asymmetric horn? These are beasts.

[Note to Matthias, et.al.: These are TWO-LAYER beasts; the front "fins" are hollow....]

The stability of location of the phantom image is their key feature; I've never experienced this before, moving from side to side and having the localized center "stay put." I don't have them widely spaced enough to generate good imaging yet, tho.

So, I guess I gotta ask, "What happened?" This approach seems to be a natural for HT, not to mention general listening. I see it used in Synthesis (no?), and Everest, of course, but no broader exploitation. Anywhere else? Is there some major drawback I don't appreciate yet, or is it just something folks don't get? Why aren't S2600 and S3100 "hot" products?

Everest White Paper here: http://audioheritage.org/vbulletin/showthread.php?t=5671

Ancillary 4660 horn and crossover info here: http://audioheritage.org/vbulletin/showthread.php?t=5629

0° top, 30° bottom:

johnaec
07-16-2005, 03:52 PM
So, I guess I gotta ask, "What happened?" This approach seems to be a natural for HT, not to mention general listening. I see it used in Synthesis (no?), and Everest, of course, but no broader exploitation. Anywhere else? Is there some major drawback I don't appreciate yet, or is it just something folks don't get? Why aren't S2600 and S3100 "hot" productsI'm guessing it's esthetics more than anything else. To start with, they're quite large for a home environment, and I believe their shape, (when visible), probably is considered too "far out" by most interior decorators, whether professional or not...

There's also the fact their placement and setup may be more critical, though I'm not really sure, because of what the design tries to accomplish...

John

Zilch
07-18-2005, 05:36 PM
Forum member tomp787 lent us a 2430H for testing to complete evaluation of the 243x "family." Here it is on PT-F 100° x 100° waveguide using biased "AM" crossover (middle) in comparison to 2431H (top) and refurbished 2435HPL (bottom). It sounds fine, though the RTA suggests perhaps not so "bright" as the others. HF extension is there, just not as much as the others. Has slightly more LF than 2431, but 2435 has the most with this crossover.

CLIO measurement results here, et.seq.:
http://audioheritage.org/vbulletin/showthread.php?p=63323#post63323

I do not pretend to hear this order of difference above 10 kHz. My argument: older listeners need as much HF extension as they can get. ;)

Younger users would likely be quite happy with 2430H; it's cheaper than the others: $249 list vs. $399 and $1399, respectively.

http://www.jblproservice.com/pdf/Transducer%20List/05%20Transducer%20List.pdf

[No, I didn't pay that for 'em....]

Mr. Widget
07-18-2005, 08:58 PM
...older listeners need as much HF extension as they can get. ;)

Wasn't there another thread that discussed that topic?

Widget

Zilch
07-19-2005, 12:16 AM
CLIO measurement results for Everest horns available here:
http://audioheritage.org/vbulletin/showthread.php?p=63333#post63333

4660 used them two-way in a limited HF extension (16 kHz) max SPL (99 dB) sound reinforcement application. By contrast, 4430 is 93 dB SPL.

Everest used them for mid/high in a hifi three-way, 100 dB system SPL.

Will they work as a hifi two-way as well? Clearly, we can extend the VHF, but the differentially variable VHF response along the horizontal axis is "troublesome." We'll see. Gotta set me up a turntable (lazy Susan) here to determine what's actually going on....

Zilch
07-22-2005, 09:59 PM
Deep throat 12" square format 90° x 50° Progressive Transition waveguides (more appropriately "horns," actually,) are WAY deeper than the 100° x 100° version (left), measuring 9-3/8" between mounting surfaces. For those unfamiliar, that's a 1-1/2" exit 2431H neodymium magnet 3" aluminum diaphragm compression driver mounted to it there. (Whew! :p )

They have substantial but smoothly contoured constrictions in the throat, apparent in the second pic. Throat gradually narrows to about 9/16" in there. Can't guess how they molded that....

Shown at bottom on RTA with 2431H's and biased "AM" crossover, they also accept 1" threaded drivers using JBL throat adapter as is shown mounted to the shallower waveguide in the top photo.

See http://www.jblproservice.com/pdf/AE%20Series/AM4212,95-WH.pdf

And http://www.jblproservice.com/pdf/AE%20Series/AM6212,95-WH.pdf

Also http://www.jblproservice.com/pdf/AE%20Series/AM6215,95-WH.pdf

How do they sound? Well, just fine. :p

A minor crossover tweak could get them playing perfectly flat, as there's beaucoup HF extension available.

Image freaks will like them better than the 100° square version since their vertical pattern is substantially tighter, and thus, they don't create as much early reflection off the floor and ceiling.

Doesn't look like mechanical time-alignment would be practical, tho; gotta do it electronically, if desired.

60° x 40° version is available for those liking the sound field even more controlled, but it requires a different crossover, at least in the PT-F version.

Still waiting on the rectangular PT-F version 90° x 50°.

[Gonna go listen while I wait, now.... ;) ]

stevem
07-23-2005, 08:39 AM
Man those things are deep! I wonder why, because the 2332 horn has about the same dispersion pattern, and they aren't a lot deeper than the 100X100 PT waveguide. The 60x40 PT version isn't as deep either. Why do you suppose this is? Any word on how long it'll be untill JBL starts making the 90x50 rectangular?

Zilch
07-23-2005, 01:18 PM
It's not apparent in the pics, but the long throat encloses an extended transition area between the 1.5" entrance and the constrictions. That accounts for about 4" of it.

I have the PT-F95 on order. If the PT-H is any indication of the requisite geometry, I can appreciate why they're not making it.

The rectangular SR horn alternative may be coming in soon, too. I believe TimG has these, but has not reported on his testing of them yet. It's 1/2" taller at 7" x 12"; from the drawing it does not appear to be as deep as the PT-H95:

http://www.jblproservice.com/pdf/SRX700%20Series/SRX712M.pdf

And don't forget the really cheap one for 1" thread-on drivers, now also called a PT waveguide. It's a surprising performer, and is what led me to pursue these others for the 1.5" neo drivers:

http://www.jblproservice.com/pdf/AE%20Series/AC2215,95-WH.pdf

Zilch
07-23-2005, 01:38 PM
Under test using a forum member's new 2431H's, which produced the RTA curves above. Note depth in comparison to the L200's they're sitting on here.

Excuse the clutter, please. It's my proprietary approach to room damping. :D

Zilch
07-24-2005, 03:31 PM
Man those things are deep! I wonder why, because the 2332 horn has about the same dispersion pattern, and they aren't a lot deeper than the 100X100 PT waveguide. Does 2332 have the same mounting hole patten? 2431 and 2451 the same?

There's apparently another one, 75° x 50°, I haven't tried, but it looks deep also:

http://www.jblproservice.com/pdf/SRX700%20Series/SRX715F.pdf

Simple crossover, a plus. ;)

[I ain't doin' no 2352. Nope, nope....]

OH, and H9800, of course. :p

stevem
07-24-2005, 05:47 PM
Does 2332 have the same mounting hole patten? 2431 and 2451 the same?

The 2332 has two 4-hole bolt patterns. The inside ones are about 2 1/4" apart, and thats what fits my 2450SL drivers. The outer bolt circle holes are about 3 1/4" apart. Maybe for the 2451? The PT wave guides have the same 4-hole bolt circle of 2 1/4" spaced holes, in addition to another two holes for I don't know what. What pattern do the 2431s use?

stevem
07-24-2005, 05:52 PM
By the way, I pulled out my 100x100 square PT waveguides to give 'em another try. I like them better this time, because they seem to put more HF into the room, and I don't get the feeling I need a VHF driver. I'm going to play around with them some more. I once read that the best thing about this hobby is that when you change something, It sounds better, and when you change it back it sounds better again! True!

Zilch
07-24-2005, 06:06 PM
The PT wave guides have the same 4-hole bolt circle of 2 1/4" spaced holes, in addition to another two holes for I don't know what. What pattern do the 2431s use?243x drivers bolt direct to the 4 holes in the PT waveguides. The extra two holes in them align with pins in the optional throat adapters (for 1" thread-on drivers) in the proper orientation vis-a-vis throat constrictions in both the waveguides and the adapters.


I like them better this time, because they seem to put more HF into the room, and I don't get the feeling I need a VHF driver.Yup, that's the prime objective here. As long as the driver and crossover can provide the requisite HF extension gracefully, two-ways RULE!

[Well, there IS other stuff gotta happen, too.... :p ]

2332 is a 90° x 40° "Optimized Aperture" horn. Sebackman tried to use 'em two-way with 2451's, and while they measured O.K., he ended up adding VHF drivers:

http://audioheritage.org/vbulletin/showthread.php?t=3774

"The roll off proved difficult to cure through the XO's so I added two tweeters." Didn't try passive HF boost, apparently.

I'm wondering how they'd play with 243x's, which appear to meet OA design criteria. Anybody got a pair of 2332's they'll send here to try?

2451 has 4-1/2" mounting bolt circle. 2450SL has 3-1/4", same as 243x, looks like. I recall now 2332 has holes for both:

http://audioheritage.org/vbulletin/showthread.php?t=3283&p=34688

stevem
07-24-2005, 08:54 PM
Zilch, do you happen to know what the lowest recommended crossover frequency for the larger (12" by 12") PT waveguides is? So far I've been using 1.2khz, but the 2450SL will go a lot lower (500 hz).

Zilch
07-24-2005, 09:20 PM
Do you happen to know what the lowest recommended crossover frequency for the larger (12" by 12") PT waveguides is?There's nothing published on that. All we can do is extrapolate from how JBL has used them in combination with results of our own measurements.

I'm using them at 1 kHz, but from our testing, even that's pushing it. These are "High-Frequency" PT waveguides according to the JBL Tech Note. See the Horn/Driver thread:

http://audioheritage.org/vbulletin/showthread.php?t=6050

Try it, test it. My own guess after re-reading: 800 Hz, maybe, if driver geometry works in your favor. General purpose drivers (2426 and LE85) played a bit lower than 243x's on them. See Post #9 over there.

500 Hz? No way....

Zilch
07-26-2005, 11:40 AM
"AM" crossover (w/Giskard's HF mod) modeled in X3P includes HF driver/waveguide response (2431H/PT-F1010). LP is N3134 (4430) and 2235H.

Looks like RTA curve, very familiar.

Gettin' close to having a handle on what's happening here :p :

[Tweak with impunity, now....]

Zilch
07-26-2005, 02:21 PM
Tweaked, with box response (B380) included, +/- 3 dB from 30 Hz. to 19.8 kHz. Another try, I got within half that, but I like this "room corrected" response slope better.

HF response transcribed from here: http://audioheritage.org/vbulletin/showthread.php?t=6050&p=57027

X3P calls my T/S parameters for 2431H/PT-F "bogus." Tough noogies, X3P; I averaged actual WT2 values for 6 drivers to get those numbers. :p

Note to Guido: Blue @ 10 kHz is per original AM schematic (4.0 Ohms, 0.08 mH), red is as JBL produced it (2.5 Ohms, 0.04 mH), the values we're using. Surprising it makes such a huge difference (~4 dB).

Powerful stuff....

Guido
07-26-2005, 03:34 PM
This looks so damned GOOD :)
Seems XoverPro is a nice toy :D

Zilch
07-26-2005, 03:38 PM
This looks so damned GOOD :) It's time you BUILT 'em, dude.

I'm TIRED of havin' all the fun here....:p

Ian Mackenzie
07-26-2005, 03:48 PM
Excellent.

Ian

Lancer
07-26-2005, 03:49 PM
Seems XoverPro is a nice toy :DIt needs to be a bit more open-ended.

Zilch
07-26-2005, 04:20 PM
It needs to be a bit more open-ended.Yup, the topology is rigidly structured.

It'll let me do notch filters now, but it won't let me plug them in. :(

[Don't need 'em, tho, looks like....]

It's only by chance I was able to get it to accept the AM circuit in the EQ section.

Zilch
07-28-2005, 05:39 PM
Surprisingly affordable ($62.87 retail) cast aluminum 2332 "Optimized Aperture" 90° x 40° horn is the same size as PT-F (12" x 6.5"). 2431H driver bolts on directly using the smaller diameter set of bolt holes provided in the flange. 1.5" throat entry rapidly constricts to now familiar racetrack oval.

[That sharp edge there can't be right, can it?]

Zilch
07-28-2005, 05:48 PM
2332/2431H performance on N3134 (4430), 3110A (wrong impedance), and "AM" crossovers. HF extension is clearly there in all cases, though there's something anomalous going on between 10 and 14 kHz. Nothing untoward in the impedance sweep.

Looks like original AM HF boost components may be better suited to this horn. For now, we KNOW how to make them listenable (bottom). :flamer:

[Sounds good, actually....]

Zilch
07-29-2005, 10:51 AM
Followup: Tracking down the "problem."

See the DMS-1 Tech Note, which discusses the 2332:

http://www.jblpro.com/pub/technote/tn_v3n01.pdf

Most notably, in Fig. 10, vertical beamwidth doubles briefly above 10 kHz, no doubt with concomitant drop in SPL.

Fig. 11 shows active compensation voltage drive to "fix" it. After the boost, 18-20 kHz is actually attenuated for flat response. :hmm:

"No compression driver system made by anyone can produce equivalent output levels with as low distortion."

That's with 2450SL-A driver. I wonder how these measure distortion-wise with 2431 and 2435 drivers....

[Interesting discussion of 4430 design philosophy there, too....]

stevem
07-29-2005, 12:03 PM
OK, it looks like you have every (or just about!) flavor of horns for use with 1.5" exit drivers. Can you tell us which you prefer, and in what order? Thanks!

Zilch
07-29-2005, 12:56 PM
Actually, I have one more coming in, the 90° x 50° SR horn used in SRX-700. Supposedly they shipped this week. [Yeah, yeah....]

I also want to try a couple of crossover tweaks with 2332's this weekend; I'm presently listening to them using digital EQ, and probably not getting the best performance out of them as consequence.

I'd like to get others' opinions on them, as well. Several forum members are likely coming by in the next few days. The differences are subtle; we're well past 2370A vs. 2344A now.

At this point, it's more about soundfield patterns than anything else, after optimizing the crossovers for each horn variant. 243x seems to work well on any of them, at least above 1 kHz. These are competent drivers; we've tested them to death here....

stevem
07-30-2005, 03:17 PM
I also want to try a couple of crossover tweaks with 2332's this weekend; I'm presently listening to them using digital EQ, and probably not getting the best performance out of them as consequence.

In case you haven't discovered this already, being metal the 2332 will ring like a bell if you just set it on top of your speakers and play it. I mount it in an open backed box, and use a layer of putty to damp it. This makes an audible difference.

Zilch
07-30-2005, 06:04 PM
In case you haven't discovered this already, being metal the 2332 will ring like a bell if you just set it on top of your speakers and play it. They're certainly "crispy" I'll say. Kinda like them, actually.

Don't know why it's so damn tough modeling a crossover for them, tho. They're virtually flat from 1.05 kHz to 8 kHz (+/- 1.8 dB); then they go all kinkoid. Maybe there's a reason JBL only used them with active EQ. :p

Only about 12 dB total compensation is required, but I note JBL's disclaimer when using their analog controller: "... additional system equalization may be necessary to fine tune the systems to the desired room response curve." Quite apparently so....

[Need better tools here, maybe....]

Zilch
07-31-2005, 12:02 PM
For those interested in the frustrating details of this process:

1) Voltage drive required for DMS-1, 2450SL-A on 2332 horn (right).
2) What I've got so far for 2431H on 2332 horn (red).

If I could get it more nearly level between 1 kHz and 8 kHz, I'd be done with it. :banghead:

Boosting in the crossover region with digital EQ is a bad deal; it forces the 2235H woofers to play more where they don't like to and sound bad....

Guido
07-31-2005, 02:57 PM
Hi Zilch!

Why messing around with those DMS Horns? Just for fun?

Zilch
07-31-2005, 05:25 PM
HEY, Guido!

Just tryin' 1.5" 90° x 40° - 50° alternatives while we wait for JBL to get around to making PT-F95, part #338650-001, which, unlike the previously presumed unavailable PT-H1010, really ISN'T available, since JBL has apparently never produced it. :p

While they're a departure from the 4430's 100° x 100° pattern, we assume there are some advantages in minimizing early reflectons off the floor and ceiling.

My own designs incorporate sloped baffles, like L200, to keep the cabinet height down. It's no coincidence that everybody tilts their "lowboys" up or mounts them up on stands. But, with constant directivity, that pushes the ceiling reflections closer as well. I THINK I hear a difference in clarity between PT-H95 and PT-H1010 used that way, even with 10' ceilings here.

The concept of interchanging horns to vary the sound field was appealing. However, it's now clear that each pattern within the same waveguide family requires a different crossover filter. It makes sense, of course, as each concentrates the available acoustic energy differently throughout the spectrum. Just didn't think about it until it smacked me. I'm gonna have to commit here soon.

Then, there's the whole "ambience" debate.

[Send me prototype PT-F95's please, JBL! I'll work 'em over for ya.... :D ]

Ian Mackenzie
07-31-2005, 09:00 PM
Zilch,

Even cone based systems have varying Di versus frequency but this hardly gets a mention.

Perhaps the noteably issue is the soft/hard edge of various horn types / geometry.

Again, those reflections can be good or bad depends on taste and the speaker location choices in the room.

Frankly I have come to like the directed sound of the 43XX, others prefer the 100 x 100 thing......but are voices really 10 foot square? Nup.(in a highly reflective room)

If on the other hand my room was totally dead i might prefer the 100 x 100 thingy.

Ian

Zilch
08-05-2005, 04:40 PM
90° x 60° (50°) SRX horns for 1.5" exit drivers are 0.5" taller than PT-F's. In many respects, they're more similar to 2332's:

They're cast aluminum, and ring like bell.
They play with a pleasant "crispness."
They require a filter similar to 2332.
2431H's bolt directly on, but through the face of the horn. HUH?

No throat constrictions involved, they just pour straight on.

RTA shows performance on AM crossover. They're flatter off-axis; the HF peak diminshes....

Seek filter intelligence here: http://www.jblproservice.com/pdf/SRX700%20Series/SRX712M.pdf

ACK! Four notch filters. Maybe I just use AutoEQ.... :p

[I think these are in Bo's new monitors, well appreciated by the Angelz....]

B&KMan
08-05-2005, 10:28 PM
Omnidirectional;)

Where do you dig out all that stuff ?
Do you have a JBL Mine ?


YIAH !!!!


INCREDIBLE

IT LIVES IN THE "" ELDORADO"" OF THE JBL


LUCKYMAN...

;)

B&KMan
08-05-2005, 10:48 PM
Zilch,

Even cone based systems have varying Di versus frequency but this hardly gets a mention.

Perhaps the noteably issue is the soft/hard edge of various horn types / geometry.

Again, those reflections can be good or bad depends on taste and the speaker location choices in the room.

If on the other hand my room was totally dead i might prefer the 100 x 100 thingy.

Ian

I feeling, you have realy too much variation on set-up mesurement. your room is as possible same at all set-up, if you put out or foward big object or speaker, you altered the relation of speaker and room..

Put a tempory mark on floor and keep smal laser for calculate oreintation angle... no big expense but really benefit for control mesure repeatability.

Maybe you found in internet a module or other gadget to determine the echo in room in regard of 1/3 octave... it is realy important for determine if your room is too dead or too live or splendid...

remember the mic free field is realy sensible in angle (this is not a random mic)

so displacement mic is all the time put at pointer (o degree) on small source driver...

other point it is critical to go out of 6 feets on mic because your presence is altered your response....

mic ideally is upper than 1.2 m but it is not possible....

in general, the 3 big modal response room is appear in in botton level frec and it is a major peak and hole response...

the axial and tangential mode produce the flutter over mid and high frec and it is easy trapped by damping in good place. In same time, this absorbant operate a control echo...

the rule is arround 60 % surface traement expose excellent result, not too dead, not tooo live. .4 at .6 RT60 isappear conform to standart architectural.

for mesure mode see pict :

Put speaker in one corner and put mic mst big longer distance as possible and in double opposite corner. start RTA and voila peak is modal response room

same in parrallele for axial.


I hope this ip is interesting.

:cheers:

Zilch
08-05-2005, 11:56 PM
SRX712 voltage drive for 2431H:

Top = basic filter
Bottom = after notching

:hmm:

Field application of the technology at very bottom.... :p

B&KMan
08-07-2005, 01:06 PM
Field application of the technology at very bottom.... :p


do you have personnaly mesured the effect in this field???

:p

Jean

B&KMan
08-07-2005, 04:07 PM
Field application of the technology at very bottom.... :p

-----------------------------

HEY this is a matched pair.... :p

-----------------------------

the sock is same profile than grill :blink:

-----------------------------

this pair is sound problably very good.... :applaud:

-----------------------------

Zilch
08-07-2005, 10:49 PM
Response curve of 2431H's (two averaged) on SRX712 waveguides. Very similar to 2332's (previous page).

For comparison, same drivers on PT-F waveguides, which are apparently doing a better job of dispersion above 10 kHz, i.e., better Directivity Index:

Zilch
08-09-2005, 11:49 PM
At the risk of y'all thinking I'm makin' this up, here are the results of a simple test with the three 90° x 50° waveguides currently under evaluation.

Method: EQ flat 22.5° off axis, half of horizontal spec. Measure on axis. All with same 2431H driver.

This is how I normally EQ, mic in middle, aimed at speakers separately, left and right.

Note: RTA sensitivity is twice what I normally post. Here, 2.5 dB per dotted line.

1) 2332 flat off axis (Beautiful!)
2) 2332 on axis :(
3) SRX712 flat off axis
4) SRX712 on axis

ACK!!

Zilch
08-09-2005, 11:52 PM
PT-H95, same two conditions. No wonder those aluminum horns sound "crispy." It may just be they need to be mounted and damped as suggested above, but I'm bettin' PT waveguides have directivity under substantially better control.

Admittedly, I'm cuttin' a fine line here: +/- 2.5 dB.

O.K., O.K., I'll mount 'em before I give up on them.... ;)

Ian Mackenzie
08-10-2005, 04:07 AM
Zilch,

Nice work, it would appear the 2332 Di index narrows above 8 kerts.

Ian

Zilch
08-10-2005, 12:46 PM
... it would appear the 2332 Di index narrows above 8 kerts.Yup, and that may be the root of Sebackman's difficulties using it two-way in his HT. Looked good in measurements, but HF couldn't be successfully EQ'd. HF extension isn't worth a whit if it crashes off-axis in a constant-directivity system.

Which has led me to review the published beamwidth, DI, and HF polar plots of the various PT waveguides in acutal product. They are shown on the various spec sheets here:

http://www.jblpro.com/ae/index_B.html

PT-F1010 looks the best and flattest, I think, though JBL doesn't make a product using that one with 2431H for direct comparison, just 1" drivers with throat adapters.

It certainly speaks to the utility of these with 2418H-1, 2426, et.al., tho.

My avatar shows the 2431H/PT-F1010 combination for those new to this thread and wondering what the heck this is about.

Tech note regarding influence of DI here:

http://audioheritage.org/vbulletin/showthread.php?p=64269#post64269

"In general, a system with a relatively smooth on-axis DI can be equalized for flat power output over a wide frequency range. A system which has a rising on-axis DI cannot be successfully equalized, because the on-axis response will tend to rise at high frequencies."

As illustrated above, presumably.

What's the relevance? Flat DI is part of 4430's "magic" formula, as documented in the tech note. If you wanna play constant directivity, it must be uniform throughout the system frequency range....

stevem
08-11-2005, 03:20 PM
Yup, and that may be the root of Sebackman's difficulties using it two-way in his HT. Looked good in measurements, but HF couldn't be successfully EQ'd. HF extension isn't worth a whit if it crashes off-axis in a constant-directivity system

Zilch,

I had mentioned that I got my pair of 2435s yesterday, and I tried them first on the 2332 horn. The response was very flat and then rolled off fast above (I think) about 8 or 10 khz, which I expected with a CD horn. When I tried to boost the highs as I do with my 2450SL, I couldn't get them flat, and they still exhibited a roll-off from about 12k hz (I'm going from memory here) on up. I mention this because I saw a pronounced notch in the HF somewhere around 10 or 12khz, and it looked a lot like the response you were getting with the 2431s on the 2332. The 2450SL, on the other hand, does not show any such notch, and is easily EQ'd out to 20khz with a simple shelving filter. When I put the 2435s on the 100x100 PT waveguides, I still could not EQ to 20Khz, but the notch disappeared and the roll-off was smooth. Do you think there is some type of incompatibility with the 2435/2431 drivers and the 2332 horn that doesn't exist with the PT waveguides? Do you have another 1.5" exit driver you can try with the 2332 to see if this is the case? I'm just curious.

Zilch
08-11-2005, 05:07 PM
Hi, Steve,

I'm pleased to welcome another member to the PT/243x quest!

Regarding the notch, see http://audioheritage.org/vbulletin/showthread.php?p=64514#post64514. 2332 is an "Optimized Aperture" horn, and may not work well with these other drivers, as you suggest: the phase plug might simply be wrong. 2431 and 2435 are the only 1.5" drivers I have here, so I can't check it out.

I get essentially the same response with SRX712 horn as well, though, and that one JBL uses with 2431H. They're kinda shy about publishing the beamwidth and DI data above about 12 kHz, tho, and the response curve reflects similar "problems."

http://www.jblpro.com/srx700/PDF/JBL.SRX712M.pdf

Same notch in the frequency response here:

http://www.jblpro.com/srx700/PDF/JBL.SRX715.pdf

I can get them flat, but not both on and off axis concurrently. These combinations are "kinky."

Look at the beamwidth and DI of DMS-1. Even with the proper driver, 2332 goes weird between 8 and 10 kHz. The recommended voltage drive for it reflects the requisite compensation.

You'll have some difficulty pushing the 2435 to 20 kHz, even on PT waveguides. It does not exhibit the HF extension 2431 does, perhaps because of the the ferrofluid. Allegedly, 2435 is "pistonic" out to 17kHz, a good feature, if real.

The rolloff is smooth, as you have seen, though, and passive EQ is easy with AM HF filter. Use active EQ on top of that, and it will push. I don't know what the quality of that response is, tho. It's not as if I can hear it up there.... :p

stevem
08-12-2005, 10:14 AM
What's the diifference betwen the 2431 and 2435? Is it the diaphram material? I can't see applying so much boost to try and get the top flat of the 2435. I'm going to try finding a suitable tweeter. Is the 045Be driver and horn available to us mere mortals? I'm going to check out the TAD ET703 as well. Any other suggestions?

Mr. Widget
08-12-2005, 10:56 AM
I'm going to try finding a suitable tweeter. Is the 045Be driver and horn available to us mere mortals? I'm going to check out the TAD ET703 as well. Any other suggestions?

This is Zilch's Quick and Dirty thread.... we don't speak of tweeters here.:D

Though I agree with you about excessive HF boost. In my recent experiments it seems the phase issues related to adding more than a few dB of EQ are detrimental to the overall coherency of the soundstage.

Here is a bit from Garry Margolis from his 1976 article, "Inside the Studio Monitor"

Zilch
08-12-2005, 11:48 AM
What's the diifference betwen the 2431 and 2435?The full exposition of the various 243x drivers begins here:

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=27&p=54744.

Notably 2431H is "A version of the 2430 with a narrower coil milling and flat surround for more extended HF response." 2431H is .002" 5052 aluminum; 2435HPL is .0016 Beryllium foil and uses ferrofluid.


... we don't speak of tweeters here.http://audioheritage.org/vbulletin/images/smilies/biggrin.gifI DID suffer a momentary lapse of reason at one point:

http://audioheritage.org/vbulletin/showthread.php?p=46524&highlight=sacrilege#post46524

Zilch
08-12-2005, 01:09 PM
For the sake of discussion, here's my two factory rehabbed 2435's just taken on PT-F1010 waveguides (PT-H being similar in earlier measurements,) with expanded vertical scale, 2.5 dB per dotted line, on AM crossover, which provides about 4 dB less "boost" than is used with 2426 in 4430, IIRC.

I'd have no qualms about tweaking the filter or EQ'ing 2.5 dB to make them more perfectly flat, though I'd consider the exercise "academic." They sound fine as is.

Also, Steve, your eBay 2435's could go back to JBL for confirmation of performance to spec. Both of mine needed gap cleaning and ferrofluid recharge; I understand yours are from the same source.

We also have the semantic issue of "boost." I'm not boosting anything here in the sense of adding HF drive as an active EQ would do. These filters reduce power selectively at the lower frequencies to flatten the response. It's semantic in that there's still a differential in the amount of power the driver receives at various frequencies, with HF getting the most, hence, "boost."

Supposedly, these drivers move mass breakpoint further into the HF region than earlier designs, reducing the magnitude of that differential. Indeed, they seem to require less total compensation, as noted above.

I suppose it boils down to an argument favoring beamy exponential horns. Having to equalize compression driver power response is inherent in using them above mass breakpoint. Doing it electrically versus acoustically is the question. Otherwise, use a tweeter, and buy all of THOSE compromises.

'Course, there's those who contend that compression drivers, themselves, constant directivity, and 4430's all SUCK hugely, in which case there's not a lot on the table here for discussion.

[We will persevere.... :p]

stevem
08-12-2005, 08:49 PM
I don't uinderstand why the 2435 has poor high frequency extension, at least compared to the 2450SL, which has a larger 4" Titanium diaphram. Isn't the 3" Beryllium diaphram lighter and stiffer? All of the TAD drivers use Beryllium domes (although I think they are made differently). How do they perform? And I don't think the issue is ferrofluid, unless they're using 30 weight oil,;) because there are a lot of ferrofluid tweeters on the market that don't have any problems with HF extension.

I'm curious about the "two-stage phase plug" design that is used in the 2435. Does anyone here know anything about it? What does it look like, and how does it work? Can it cause a lack of HF? Are all the 24xx driver's phase plugs this same design?

Mr. Widget
08-12-2005, 10:01 PM
I'm curious about the "two-stage phase plug" design that is used in the 2435. Does anyone here know anything about it? What does it look like, and how does it work? Can it cause a lack of HF? Are all the 24xx driver's phase plugs this same design?

Don't really know much about the 243X driver phase plugs, but I am fairly certain that they all use the same phase plug design. As far as a phase plug determining the UHF capability of the driver, it absolutely plays a significant role in the upper frequency capability of a given compression driver. The phase plug and the mass break point are the two key factors in determining a driver's HF capability. The mass break point is determined by the mass of the diaphragm relative to it's flux density, it's stiffness, and it's suspension's compliance.

This plot show that 4 drivers with different diaphragms behave very similarly in terms of UHF extension. They all share the same phase plug... this is perhaps where a plane wave tube would come in handy, as the H9800 may also be the limiting factor so we can't definitively say what is causing the UHF loss.


Widget

Zilch
08-12-2005, 11:13 PM
I couldn't find the 2450SL data sheet, but here's the 2450:

http://www.jblpro.com/pages/pub/components/2450.pdf

Comparing the PWT responses, I'd say the 2435 crashes precipitously at about 17.5 kHz. It requires less than half the compensation of 2450 to play flat up to there, however. See also 2431H in blue at bottom. Ignore the glitches, and it doesn't crash, it just kinda gracefully dives from around 13 kHz. :p

To play flat on 2380 horn, 2450 requires 20 dB of compensation. 2435 would require 24 dB, looks like, to make 20 kHz solidly, a dubious endeavor. I'm operating with around 14 dB of total compensation now using 2431, equivalent to what 4430 requires for "flat," 10 dB of that occurring in the last octave.

Why does this matter? Distortion increases with rising power and frequency. The harder we have to push it up there, the worse it gets....

stevem
08-13-2005, 10:52 AM
I couldn't find the 2450SL data sheet, but here's the 2450:

http://www.jblpro.com/pages/pub/components/2450.pdf

Comparing the PWT responses, I'd say the 2435 crashes precipitously at about 17.5 kHz. It requires less than half the compensation of 2450 to play flat up to there, however. See also 2431H in blue at bottom. Ignore the glitches, and it doesn't crash, it just kinda gracefully dives from around 13 kHz. :p

To play flat on 2380 horn, 2450 requires 20 dB of compensation. 2435 would require 24 dB, looks like, to make 20 kHz solidly, a dubious endeavor. I'm operating with around 14 dB of total compensation now using 2431, equivalent to what 4430 requires for "flat," 10 dB of that occurring in the last octave.

I believe that the 2451 is almost identical to the 2450SL, not the 2450 (which has a throat piece). Anyway, I use 10db of boost starting at 8.28khz and shelved upward at 12db per octave to achieve basically flat response to 20khz on the 2332 horn. Of course, there is the 1 or 2 db tweak here and there to get the response perfectly flat. Interestingly, I discovered that the DMS-1 is listed under JBL's "Tunings" in their tech section, and this is exactly the same boost they recommend. The DMS-1 uses this same driver and horn.



On the other hand, with the 2435 I've tried the same 10 db boost at 8.28khz, with another 9db boost at 16khz (also shelved upwards at 12db octave), and the response is still not flat. This driver, as it is now, is really a midrange, and not a HF unit, although you are correct in that it does go higher and flatter than the 2450SL before any boost is applied. That's why I am surprised that I can't get it flat too.

Zilch
08-13-2005, 11:42 AM
I believe that the 2451 is almost identical to the 2450SL, not the 2450 (which has a throat piece). O.K., here's the 2451. I'll leave the 2450 info up for comparison.

I'd say the same analysis applies.

Looks like 2451 actually requires about 3 dB MORE HF boost than 2450, but it's apparent that the 2332 horn's DI is doing part of the job (the lion's share in the VHF region) from the compensation you are successfully using.


This driver, as it is now, is really a midrange, and not a HF unit, although you are correct in that it does go higher and flatter than the 2450SL before any boost is applied.Well, "...is really a midrange..." may be a little extreme. I'd call it a HF driver. Its sharp cutoff at 17 - 18 kHz disqualifies it for UHF, though, clearly.

Let's have a look at how it's used in Vertec:

http://www.jblpro.com/vertec1/new_vertec/pdf/VT4889.pdf

Note sharp cutoff. YIKES, three 2435's per unit! (Not cheap, I betcha....)

VT4888 uses dual 2431's. Note flat extension to 20 kHz at -15 dB:

http://www.jblpro.com/vertec1/new_vertec/pdf/VT4888.pdf

A similar HF "shelf" occurs in the SRX700's that use them, as well:

http://www.jblpro.com/srx700/PDF/JBL.SRX715.pdf

If 18 kHz isn't high enough for you, I'd try a pair of 2431H's before giving in to tweeters. 4430 was only spec'd to 16 kHz:

http://www.jblpro.com/pub/obsolete/443035.pdf

By way of perspective, you're already better than that with your 2435's on PT-H waveguides, using minimal compensation, and it's pistonic, for the most part, i.e., breakup mode only in the last 1/5 octave.

"The 2435 has a performance envelop[e] that far surpasses all commercial[ly] available compression drivers."

http://www.jblpro.com/vertec1/doug%20button%20258%20final%20rev%20c.pdf

Would only it actually played like that.... :p

Zilch
08-13-2005, 02:25 PM
...but are voices really 10 foot square? Nup.Heh. Actually, the DI of the spoken voice is 3 dB, and the Directivity Factor (Q) is 2.

That's MUCH bigger than a 10-foot square, and cannot be faithfully reproduced by anything less than an array of 4344A's. Think "Hemisphere...." :p

Zilch
08-14-2005, 01:37 PM
On the other hand, with the 2435 I've tried the same 10 db boost at 8.28khz, with another 9db boost at 16khz (also shelved upwards at 12db octave), and the response is still not flat.Try SRX712 tuning for 2435 on 2332 horn. I have found the behavior of that driver/horn combo to be similar, above.

It's a 12 dB boost at 15 kHz, Q=3.41 after 2.5 and 3 dB (Q=.94) cuts at 2.5 and 6 kHz, respectively.

For PT-H waveguide, try am6212_00 tuning here: http://www.jblpro.com/ae/dsp_tunings.html

Consider these "Generic" 243x tunings, and tweak as required. ;)

stevem
08-14-2005, 06:34 PM
Thanks, Zilch, I will give these a try. I really need to fool around with it some more, as I haven't spent enough time on it yet.

I am a bit puzzled by the plane wave tube responses of the 2435 and the 2450SL. According to that data, the 2435 should have plenty of top end.

Zilch
08-14-2005, 07:24 PM
I am a bit puzzled by the plane wave tube responses of the 2435 and the 2450SL. According to that data, the 2435 should have plenty of top end.The second 2435 one? It's 1/3 octave smoothed.

If it actually played like that, it'd show in the Vertec specs. :p

Lemme get some performance data here....

Edit: O.K., here's 2435HPL drivers #5 and #6 on PT-F waveguides. Results on PT-H should be similar. I took down the data, but the two drivers were identical (within 1 dB,) so no averaging or normalization is required. This is 1/3 octave, of course, so there is inherent smoothing. Second column in from right is 18 kHz. 15 dB total compensation will get them to play flat.

[Kinda looks like Fig. 29 PWT curve, above, I'd say. PT waveguide DI must be quite good....]

To do this yourself: put a 47 uF capacitor in series with the driver for safety, bypass all EQ, and play your RTA, mic on axis at 0.5 M. We'd like to see how yours are performing in comparison. :yes:

Below those, the same two drivers and waveguides on AM crossover. None of this is from archives; I just now did it. If you can't make similar happen, I'd again say those drivers need to go back to Northridge for rehab.

Note: These AM filters are optimized for 2431H's. Even so, the 2435HPL's are playing within +/- 1.5 dB on them. A couple of tweaks could make these play virtually flat through 20 kHz here. Alternatively, a small amount of external EQ used with them would make it happen.

How can this be? The original ('00) PWT and Vertec response curves say it's not there. The empirical results both here and in Mr. Widget's CLIO measurements above say these are nearly as good as 2431H's in HF extension. Answer: I DON'T know.... :applaud:

See also: http://audioheritage.org/vbulletin/showthread.php?t=6050&p=63324.

Zilch
09-01-2005, 12:52 PM
Update: S2600 horns are supposed to come complete with throats. They didn't.

None in U.S., apparently, they're coming in from France.... ;)

Earl K
09-01-2005, 01:27 PM
Update: S2600 horns are supposed to come complete with throats. They didn't.

- That's good news !


None in U.S., apparently, they're coming in from France.... ;)

- Interesting. French metal maybe ? :D

jackgiff
09-12-2005, 02:50 PM
First, my hat is off to Zilch for sharing his knowledge with us, and for doing all the research to tell us how build these guys. They sound absolutely great. I have pretty much always been a two way guy, but the 4312's and 4412's gave me reason to reconsider. No more. Two ways rule!!! I need to find Zilch's magic 4 inch port blockers. My hardware store doesn't carry anything that will fit the bill, so will probably end up making them from 3/4 inch MDF. Here are the pix.

And by the way, sonofagun's foam grilles look pretty nice on them too, don't you think?

Earl K
09-12-2005, 03:21 PM
Hey !

Very Sharp Jack ! :)

So , do tell us , what components did you use ( out of Zilches many 2-way configurations ) ?

:p

ps ( yep / love the grills )

Zilch
09-12-2005, 03:28 PM
Izzat ROSEWOOD there? :bouncy:

They've certainly got high WAF!

Well, of course, I'm greatly pleased that you like them.

Looks like you're set up for A/B testing against 4412's. That's TOUGH competition in the mids and highs, for sure.

Your local plumber's supply house will likely have the port plugs. I think I saw them at Home Depot, also.

The beauty of them is you can switch in and out as desired. Plug one port for extended bass, leave both open for tight bass.... :)

jackgiff
09-12-2005, 03:34 PM
I had a hard time finding 2235's, so bought a pair of 2225's and had Orange County Speaker recone them as 2235's. The 2431's seemed to be the best bet, so that is what I used. Zilch was a real blessing to my project, but tested so many drivers, I got confused about which ones to use. I am a happy camper now though. In fact, they have replaced my original factory purchased 846A Valencias in my office, but were really meant to be in our new home when it is done.

Yes, that is rosewood. Didn't finish as nice as the 4412's, but still looks OK.

Zilch
09-14-2005, 11:28 PM
H3100 throats came in.

Here --- havva seat....

:D

Zilch
09-16-2005, 12:08 AM
1) H3100 driver mount.

2) H3100 throat compound transition incorporates a broad constriction including the familiar racetrack oval.

3) - 5) Three views of the interior of the cast aluminum throat. Note finish quality....

Zilch
09-16-2005, 12:14 AM
6) Half of throat mounted to horn.

7) LE85 completes horn assembly. Exterior of throat looks likes it's smashed on the side, but that's where the final transition to rectangular occurs. Even that is curved....

Zilch
09-16-2005, 12:32 AM
1) Impedance of LE85 on H3100.

2) Impedance of 2426J on H3100. Error in title (2226J) is too hard to fix. :p

3) RTA LE85 with 3110A crossover, mid = min, HF boost = max (not enough) per stock 4660.

4) RTA 2426J, same conditions.

5) Citation 7.4/H3100 in Everest orientation.

These horns do not exhibit phase or response anomalies found with 2346. I'll verify this by retesting the Everest horns.

What's this have to do with 4430?

It's a Biradial two-way with a decidedly different dispersion characteristic, is all. Closer than I might ever have imagined.

[Crossover work needed.... ;) ]

B&KMan
09-16-2005, 05:46 AM
1) Impedance of LE85 on H3100.

2) Impedance of 2426J on H3100. Error in title (2226J) is too hard to fix. :p

3) RTA LE85 with 3110A crossover, mid = min, HF boost = max (not enough) per stock 4660.

4) RTA 2426J, same conditions.

5) Citation 7.4/H3100 in Everest orientation.

These horns do not exhibit phase or response anomalies found with 2346. I'll verify this by retesting the Everest horns.

What's this have to do with 4430?

It's a Biradial two-way with a decidedly different dispersion characteristic, is all. Closer than I might ever have imagined.

[Crossover work needed.... ;) ]


Hi Zilch,

Again beautiful works and juicy stuff....

euh question for you.

the slope response on 2426J it is due to electrical impedance mismatch.

the Le85 is a really beautiful response but the impedance is increased by 2 if you compare with 2426J .

It is possible to explain his phenomenon ???

Jean

Zilch
09-16-2005, 09:05 AM
It is possible to explain his phenomenon ???Hi, Jean.

There's a difference of 40 years in the diaphragms, and different driver designs, of course. Also, LE85 is aluminum with tangential surround, probably, whereas, 2426J is brand new diamond surround titanium.

I'd be reluctant to conclude anything unless I ran several of each type. This becomes a statistical exercise when dealing with drivers having indefinite histories.

Four additional points to consider:

1) Crossovers (like 3110A) with tapped inductors are less sensitive to HF driver impedance variations; I doubt it's impedance alone,

2) The 2426J response curve seems flatter, actually. It needs different HF boost (though both might benefit from more),

3) If I backed off the HF boost on the LE85 a bit, the two driver response curves might be more closely matched, and,

4) I forget the last point, now.... :p

Edit: Oh, yeah, I remember now. Note that the impedance scales are different on the two plots.

Earl K
09-16-2005, 09:16 AM
Hi Zilch


1) Crossovers (like 3110A) with tapped inductors are less sensitive to HF driver impedance variations; I doubt it's impedance alone,

- I remember seeing and reading Giskards info that created this above reference. Do you know where that post is located ? I'd love to reread it .

- Any chance of retrofitting those H3100/le85 horn combos into old L200s ?

Thanks

Zilch
09-16-2005, 09:27 AM
I remember seeing and reading Giskards info that created this above reference. Do you know where that post is located ? I'd love to reread it.Actually, my statement derives from a recent empirical determination in which I came out looking stupid for not knowing that. We pursued it relentlessly here:

http://audioheritage.org/vbulletin/showthread.php?t=5629&page=1&pp=15

I'd like to read the Giskard reference as well, if somebody can find it.

There's the throat details you asked for, above. I'm certainly glad I persisted to obtain them. JBL put considerable effort into that design.

No way could I have replicated those in plywood. It'd take some SERIOUS negotiation with Mr. Widget's CNC setup to accomplish that. :p


Any chance of retrofitting those H3100/le85 horn combos into old L200s?Lemme make some quick measurements here....

Edit: No, alas, not without a new baffle. 2344A would JUST squeeze in there above the woofer. H3100 is 1" taller.... :(

Earl K
09-16-2005, 09:51 AM
I'd like to read the reference as well, if somebody can find it.

- Then I'll see how the weekend goes for time before looking around .


Edit: No, alas, not without a new baffle. 2344A would JUST squeeze in there above the woofer. H3100 is 1" taller....

- Oh well .

:p

EDIT :
There's the throat details you asked for, above. I'm certainly glad I persisted to obtain them. JBL put considerable effort into that design.

- Those look to be well made castings. I like the sexed halves.. ( Must be French ! ) They "look" heavier than any of the previous pictures suggested .

- I assume those horizontal "sides" of the throat are of a slightly different length when forming the ??? entry angle .

Robh3606
09-16-2005, 10:04 AM
Is this what you are looking for??

http://www.audioheritage.org/vbulletin/showthread.php?t=846&highlight=Tapped+Inductor

Rob:)

Mr. Widget
09-16-2005, 10:19 AM
Rob,

I knew there was a reason we kept you around.:applaud:
That Giskard was a useful fellow too.:hmm:


Widget

Zilch
09-16-2005, 10:59 AM
- I assume those horizontal "sides" of the throat are of a slightly different length when forming the ??? entry angle .Nope, they're isosceles triangles, with the mouth being slightly wider. The 30° angle is established by the horn.

See the top pic at post #571, above....

Earl K
09-16-2005, 11:08 AM
Nope, they're isosceles triangles, with the mouth being slightly wider. The 30° angle is established by the horn.
- Okay, Thanks !

- Say Zilch , have you tried taking advantage of that seemingly "extra" 3 db HF boost ( between 10 & 20K / from the 10 db pad tap ) that's naturally builtin into those "electrically wonky" :p autoTransformers ? ( Wait; it's a feature, no it's a design flaw, no, feature !, flaw ! , whatever ,,,,,)


:)

Zilch
09-16-2005, 11:14 AM
Say Zilch , have you tried taking advantage of that seemingly "extra" 3 db HF boost ( between 10 & 20K ) that's naturally builtin into those "electrically wonky" :p autoTransformers ? ( Wait; it's a feature, no it's a design flaw, no, feature !, flaw ! , whatever ,,,,,) Yeah, it ain't enough to do the job, tho.

As Giskard suggested in the reference Rob cited above, there's easier ways to accomplish what's required.

[I'll discover them one day.... ;) ]

Earl K
09-16-2005, 11:26 AM
Yeah, it ain't enough to do the job, tho.

As Giskard suggested in the reference Rob cited above, there's easier ways to accomplish what's required.

- Well, one approach would be to design in a response bump by incorporating a filter section that rings some ( by moving LC elements closer together than a 1 octave pole-spacing, thus producing a higher Q filter compared to the typical Butterworth ) and then combining this LC with traditional resistive padding . One would want to listen to this design approach quite carefully to determine for themselves if the increase in group delay , was acceptable .



:p

Zilch
09-17-2005, 02:16 AM
I've listened to these off and on for two days now. I call them "Mini-Everests" when I have the LE14H-3 woofers angled in the requisite 30°, and "Z3100's" when they're flush. ;)

It's disconcerting at first: we're used to being able to locate and adjust the image with minor changes in our position relative to the two speakers. Once properly set up, no matter with these. The only way to move the image (which is as expansive as the separation,) is by changing the relative loudness of the left vs. right channels. Otherwise, it just stays put, rock solid.

If you move in line with one or the other of the speakers, or even slightly beyond, the image stays centered between them. You can turn your back on them and it's still there, same place, same size. :p

It's a new listening experience for me, and it took some getting used to. Once I acknowledged what was going on in my head and gave in to it, it became most pleasurable, and there may be no going back. The difference is significant. Just gotta tweak the frequency response now so they play as nice as 4430's and hope I don't mess up the effect in the process. Even as-is, these are keepers.

Perhaps it's just a cheap trick, but I LIKE it.... :)

Zilch
09-18-2005, 03:10 PM
Heh!

HEY, who stole 200 Hz? :p

They wanna be about 6' - 8' apart.

Everest instructions tell how to set 'em up.

[Maybe I should read that....]

Even the mini-horns look big in this context.

Not much bass below 40 Hz, 'cause they're about 6' out from the wall.

I jus' turn on the monster sub next door to make up for it.... ;)

"Duke" Spinner
09-18-2005, 05:25 PM
wowser ......:bouncy:

Zilch
09-18-2005, 06:26 PM
Gonna be a distinctive cabinet design, for sure.

I'll start this one with papier-mâché.... :p

[Think "Mobius."]

Zilch
09-22-2005, 12:51 PM
Several members are building 4430/4425 hybrid clones incorporating the NL200t3 crossovers described earlier in this thread by former member Giskard.

John W suggested using a laminate-core inductor in the LF section for a little more gain in the low end from reduced DCR. I thought I'd try it, and bias the HF section at the same time; only one capacitor is involved.

So, here's the parts list as built (right-click to print), a pic of the crossover itself, the system it's running on (LE14H-3 in Citation 7.4 box, 2426H on 2344A), the RTA curve (I need a damn tripod :o: ), and the schematic (right-click again). Connect the inputs in parallel to run off a single amp, or biamp, as desired.

Indeed, there seems to be a little bit more drive to the woofer, notwithstanding 200Hz, which fiends have stolen here recently. ;)

Original version here: http://audioheritage.org/vbulletin/showthread.php?p=49852&#post49852

The days of $70 2342 horns are over, apparently; price was updated to $156 recently. :(

I'll post RTA results with 2342 horns and 2418H-1 drivers once they come in. Clone builders might want to consider the $10 PT-F95 waveguide for use with 1" drivers if that price is now too dear. That combination requires a different crossover, tho, i.e., not this one.

EDIT: Yup, sounds mightily fine --- "Crispy." And I ain't apologizing for LE14H-3 anymore, now that we know the top Project Array uses 'em.... :p

http://home.att.net/~i_am_zilch/NL200t3_Parts_List.jpg

Lancer
09-23-2005, 12:46 AM
And I ain't apologizing for LE14H-3 anymore, now that we know the top Project Array uses 'em....Huh? Which dumbass asked you to apologize for an LE14H-3?

Earl K
09-23-2005, 08:04 AM
It's no coincidence, probably, that having tested 5 varieties of LE14's here now, it's the LE14H I like best. Still trying to get reliable data on them with WT2, I've switched to delta-compliance determination of Vas using this Citation 7.4 as the test box.

The REAL goal is to make a platform in which refoamed LE14A's sound good, since there's SO many of them out there that need good homes. I have a couple of thrashed ones I'm gonna try reconing to LE14H-1, if that'll work. And H-3's too, of course. Be good if they played nice, as well....

They sound kinda "rubbery."

[Just KIDDING, gang.]

So,,, how much of the above quote still holds true after 4 months ?

--or-- Have you been won-over by the newer black-coned wonders ? ;)


:p

Zilch
09-23-2005, 08:56 AM
So,,, how much of the above quote still holds true after 4 months ?It's ALL still true ('cept the "rubbery" part, of course). ;)

You can see them right up against the L200's with Giskard's 2235's in them here, so there's a good deal of "A/B" goes on. Let's just say I've got a bit more work to do before they will be indisdinguishable.... :p

The Z1 box was designed for LE14's of all variety. I chuckled when I saw Project Array makes a substantial deal of "Trapezoid."

Johnaec (who did the renderings) and I are talking about making several of them to try out. Also, the 2342 horns will fit nicely in the taller Z2 cabinet; we'll see how well they play.

Right now, I'm scratchin' my head regarding how to package LE14 with S3100 horns in the Everest alignment.

Fun stuff, this, and LE14, all kinds, continue as major participants, yup.... :D

Zilch
09-23-2005, 09:01 AM
Huh? Which dumbass asked you to apologize for an LE14H-3?Nearly everybody likes the bigger-boxed 2235's better, is all.

One forum member is building L200t3 clones with LE14A's. That's a good fit, I figure, and another reason I revisited the crossover.

I jus' have to work with LE14H-3 a little more to make them sound their best. I'll be watching for more Project Array details, schematics, in particular, with considerable interest.

Maybe LE14's deserve their own thread more fully exploring the potential. It's clear JBL likes 'em.... :p

Uncle Paul
09-23-2005, 09:13 AM
Zilch,
What is your preference between the two for a 4430 clone? Is the N3134 you built worth the extra cost and work? Have your mods to the NL200t3 closed the gap? Inquiring minds want to know!

Zilch
09-23-2005, 09:46 AM
Zilch,
What is your preference between the two for a 4430 clone? Is the N3134 you built worth the extra cost and work? Have your mods to the NL200t3 closed the gap? Inquiring minds want to know!I haven't tried the biased NL200t3 with the B380's yet, but I can tell you they certainly sound good with the LE14H-3 Citations. Biasing that one capacitor seems to have made a major difference in the high end. My originals are out on loan, though, so I can't do a direct comparison. I'll try them with the B380's this weekend for you. I'm gettin' WAY too many "Keepers" here now. :p

I'd look at it this way: NL200t3 is an easy startup for DIY 4430's, and inexpensive. It might benefit from a Zobel in the LP taken from N3134 to better match it to 2235H woofers, but the HF compensation is very good. Y'all know I have a particular fondness for the "magic" of N3134. It's gonna be hard to ever get me admit there's any equivalent substitute, particularly after my having gone to the considerable effort of building a "hot rod" pair. ;)

I'm working on matching the NL200t3 HF section to 16-Ohm LE85. I'm betting that's gonna sweeten the deal considerably. Those old aluminum diaphragms sound smoother to me and seem to have a little bit more HF extension based upon testing here, but I'm not willing to crack the seals on the LE85's for the sake of an impedance match alone. Instead, I'm gonna load my pair of D8R2421's in 2425's for comparision....

Lancer
09-23-2005, 09:56 AM
Nearly everybody likes the bigger-boxed 2235's better, is all.D'oh!

Zilch
09-23-2005, 09:59 AM
D'oh!
Hee, hee. We'll get it, eventually.... ;)

Lancer
09-23-2005, 10:10 AM
Yeah, well, I certainly understand the fascination with the 2235H so I guess if there are people out there that like it better then good for them.

Earl K
09-23-2005, 10:17 AM
Hi Zilch


Maybe LE14's deserve their own thread more fully exploring the potential.

Yeh, probably,,, but too late now . :p


jus' have to work with LE14H-3 a little more to make them sound their best. I'll be watching for more Project Array details, schematics, in particular, with considerable interest.

- I'd suggest,,, start considering a 700 to 800 hz crossover point for use with a 3" diaphragmed / 1.5" exit compression driver .
- Horns ? Some other Manufacturers come to mind.
- Here's one example from DDS ( this is setup for vertical mounting a la the "Array Series" ) .
- I'd also suggest doing what JBL does ,, politely ignoring (when they can ) the "1/2 octave lower than Fc for proper acoustic loading" rule and start exploring so called 1000 hz CD horns from other manufacturers . "Preferred Practices" for SR use & Home use really is different . You may just find that other horns have the same amount of loading as the H3100 ( for instance ) when used down to 750hz .
- DDS actually does mention 800hz in their copy. Just not as a recommended crossover point . That's understandable given the SR idustry they typically OEM to . ;)

:)

Zilch
09-23-2005, 10:19 AM
Yeah, well, I certainly understand the fascination with the 2235H so I guess if there are people out there that like it better then good for them.LE14's got a bad rap for muddy midrange due to cone mass.

To me, they play just fine, right through 1kHz and beyond....

Earl K
09-23-2005, 10:22 AM
LE14's got a bad rap for muddy midrange due to cone mass.

Heh,

- I remember that quote & I stick by it . :D
- I'd actually say "veiled" more than muddy .
- The deeper gap of the le14h-3 should have offered a bit more resolution / but so far I've heard "nadda" that would confirm that hypothesis.
- OTOH, I've heard quite a few opinions expressing a preference for the older .6" short coil ( read rising mid ) . Who would have thunk it ? :o:
:p

Robh3606
09-23-2005, 10:27 AM
"LE14's got a bad rap for muddy midrange due to cone mass."

Yeah I think the older systems where they were maried to the Le-20 is the problem. The box is too small so you can't see how low they can really go and crossing them at 1.5-2K is really pushin things. I think that's how most people have heard them. I use 14A's as subs and have 2235's and those Le-14 have nothing to be ashamed about. I think the 2235's have a bit more punch but the Le14 sounds like they have perfect pitch. You can hear every single note.

Rob:)

Lancer
09-23-2005, 11:20 AM
Yeah I think the older systems where they were maried to the Le-20 is the problem.

I think the 2235's have a bit more punch but the Le14 sounds like they have perfect pitch. You can hear every single note.You are the winner! :)

Note -
The current LE14H-1 (latest recone kit) and the LE14H-3 yield extremely similar results. They can be considered interchangable. They have somewhat of a rising response. The original LE14H-1 as used in the 240Ti and 250Ti (Hawley cone) had remarkably flat response.

Zilch
09-23-2005, 01:56 PM
You are the winner! :)

Note -
The current LE14H-1 (latest recone kit) and the LE14H-3 yield extremely similar results. They can be considered interchangable. They have somewhat of a rising response. The original LE14H-1 as used in the 240Ti and 250Ti (Hawley cone) had remarkably flat response.And the LE14A and H reconed with H-1 kits (which is all that's currently available for them,) they're better than original LE14A cones, as well, in these applications, i.e., subwoofer and "full" range to beyond 1 kHz?

Zilch
09-23-2005, 02:01 PM
Heh,

- I remember that quote & I stick by it . :D
- I'd actually say "veiled" more than muddy .
- The deeper gap of the le14h-3 should have offered a bit more resolution / but so far I've heard "nadda" that would confirm that hypothesis.
- OTOH, I've heard quite a few opinions expressing a preference for the older .6" short coil ( read rising mid ) . Who would have thunk it ? :o:
:pThe LE14H-3 has more cajones than LE14A, for sure. Kinda like LE15A vs. 2235H to me.

Do I like LE15A? Yes. Do they play in B380? Well, yes, but only briefly, while the 2235H's are gettin' refoamed.... ;)

scA7500
09-23-2005, 05:28 PM
Zilch, I have recently upgraded my A7-500's to 2435HPLs on 2352 medium format horns. Midrange is Significantly clearer than the prior 2451s on the same horn. These drivers are truly awesome. Anyone have a lead on larger back caps for the 243x? The forum has really be helpful with my project. Thanks.

Zilch
09-23-2005, 05:47 PM
Anyone have a lead on larger back caps for the 243x? Not available, to the best of our knowledge, alas. 2435HPL plays down to 800 Hz with the smaller back cap in testing. I've never heard what it sounds like down there, tho.

A recent post indicated that it was designed for maximum lower frequency output (down to 400 Hz) with the larger back cap as 435Be.

stevem
09-23-2005, 08:21 PM
Zilch, I have recently upgraded my A7-500's to 2435HPLs on 2352 medium format horns. Midrange is Significantly clearer than the prior 2451s on the same horn. These drivers are truly awesome. Anyone have a lead on larger back caps for the 243x? The forum has really be helpful with my project. Thanks.

Hey Zilch! The 2352. Isn't that the one that got away?? (I mean, the only one you haven't tried?);)

Zilch
09-23-2005, 09:25 PM
The 2352. Isn't that the one that got away?? (I mean, the only one you haven't tried?);)Heh. I ain't goin' there. Nope.

Those "medium format" horns are HUGE!

http://www.jblpro.com/pages/pub/components/23525354.pdf

[The directivity index IS good tho.... :p ]

Lancer
09-23-2005, 11:02 PM
Not available, to the best of our knowledge, alas. 2435HPL plays down to 800 Hz with the smaller back cap in testing. I've never heard what it sounds like down there, tho.

A recent post indicated that it was designed for maximum lower frequency output (down to 400 Hz) with the larger back cap as 435Be.435BE is the consumer version of the 2435 and has a larger back can to lower the useable response from around 1 kHz to around 650 Hz. It is quite happy down to 800 Hz. Slope roll-off is curved such that passive EQ is difficult. Roll-off starts around 7 kHz. Digital parametric EQ is the way to go. Watch out for latency in digital crossovers.

The 2431 is an improved 2430 and offers better HF response. It has an improved surround. 435AL is the consumer version of the 2431. They all use aluminum diaphragms with improved kapton surrounds as compared with the older 2421/2441 style diaphragms.

The 2425 is fairly breakup free up to around 15 kHz. It starts to roll off around 2 kHz and is easy to passively EQ. The aluminum diaphragm is "better" than the titanium diaphragm because it is better damped. The titanium can handle the abuse. And most recently - Aquaplased titanium is very smooth across the bandwidth and only loses about 1 dB of output at 20 kHz due to the increased mass.

Zilch
09-24-2005, 11:00 AM
Parts ordered for LE85 (and other 16-Ohm driver) compatible version of NL200t3.

The simple circuit is eminently tweakable using Spice.

Gonna be sweet, I betcha.... :bouncy:

Zilch
09-24-2005, 01:22 PM
Aquaplased titanium is very smooth across the bandwidth and only loses about 1 dB of output at 20 kHz due to the increased mass.Izzat 1 dB down evenly across the bandwidth, or just at the extreme high end?

Actually, I wouldn't mind it rolling off quicker at 20 kHz....

Zilch
09-24-2005, 06:43 PM
As requested, 2426H on 2344A, B380 LF.

Top = N3134 at "0"
Bottom = NL200t3

The latter is 5 dB "brighter"

Uncle Paul
09-25-2005, 03:52 PM
Zilch, Thanks for the comparison. The NL200t3 looks flatter than the 3134 with slightly better HF extension to boot.

In your opinion, which of the two sounds the best?

Robh3606
09-25-2005, 04:29 PM
Hello Zilch

Those full passive on the plots?? Seem ragged bellow 2.5K or so. You crossing at 1K and 1.2K??

Rob:)

Zilch
09-25-2005, 06:29 PM
Hiya, Rob. :)

All full passive there, as built, and not biamped, just LF & HF bridged together running on a single 6230 amp.

L200t3 is spec'd at 1.2 kHz, 4430 (N3134) at 1.0 kHz.

Part of it may just be the "laboratory," which is unusually full of stuff right now.

I'm most interested in the correctness of the VHF performance, but there may be some issues yet to be addressed lower down in the crossover region. It's a bit messy right now, looks like. Also thinking 'bout what's happening above 20 kHz with this.

Really waiting for 2342 horns to see the performance of the original design configuration, but it's interesting and notable that NL200t3 measures better with LE14H-3 woofer than 2235H when using 2426H on 2344A. 1.2 kHz may be a "push" for either of them.

I'm hoping you'll have some time to try out the originals and post some results, now that members are actually building with NL200t3. I'm always a bit uneasy when it's solely my own experience as basis for advice.... :p

Zilch
09-25-2005, 06:53 PM
Zilch, Thanks for the comparison. The NL200t3 looks flatter than the 3134 with slightly better HF extension to boot.

In your opinion, which of the two sounds the best?I believe I've concluded over time that I like a linear drop across the spectrum better than purely flat. At least with titanium diaphragms playing the VHF, perfectly flat usually sounds a bit harsh to me; too bright. Mr. Widget and RobH have said the same thing, if I recall.

The Behringer UltraCurve calls that contour "Room correction" and does a 1 dB/octave "tilt" of the response curve when engaged, so we're apparently not the only ones with this preference.

You can see that my N3134 does that, too, being down 5 dB compared to NL200t3 in the HF region. If I put an L-Pad on the HF output, I'd bet I could dial the NL200t3 virtually identical to the N3134 insofar as overall frequency response is concerned.

However, I must add that since I have moved the horns and crossovers back onto the LE14H-3's, I'm very much enjoying the extra "crispness" of their more flat frequency response today. Johnaec is coming over for a listen later this week, so I'll get another opinion. I'm also looking forward to hearing how aluminum diaphragms will play compared to titanium up there.

Perhaps by next weekend; I've gotta build my 16-Ohm HF version of the crossovers for that.... :)

Zilch
09-30-2005, 11:06 PM
A) 16-Ohm version of biased NL200t3 HF section, 3" x 5" board.

B) 2426J on 2344A horn.

C) LE85 on same.

D) Schematic.

E) Full range w/ LE85.

2426J is flatter.

This LE85 is 5 dB hotter above 5kHz.

Sounds fine tho.

Inductor is Jantzen 20 Ga., 1.18 Ohms, PE # 255-054.

What's happening here? There's no standard crossover providing the requisite HF boost for 16-Ohm drivers on biradial horns like 2344(A) and 2342. 3110A doesn't get it.

Converting LE85 to 8-Ohms with original aluminum diaphragms (which are alleged to sound better than the later titaniums) to run on the available crossovers is an expensive proposition, and requires breaking the wax seals of these valuable drivers. Also, there's lots of 16-Ohm 2426J's available that might be used without a diaphragm change. This reconfiguration of NL200t3 comprises a platform for working with both. There's no way I could reasonably contemplate reworking the 4430's N3134 crossovers to accomplish this.

I also want to run LE85's on H3100 horns. While this crossover is not "correct" for that, it gives a boosted HF response that my EQ can work with using minimal adjustments. Then I can compare LE85 and 2426J to see if there's any difference in the sound quality.

Guess I'll build another one and let UltraCurve do its thing here.... ;)

DRG
10-01-2005, 06:04 AM
If you are going to go to all this time and trouble you need to get set up with a decent hardware/software package.

There are 21,650 views on this thread as of right now. Maybe they will take up a collection.

I'd suggest CLIO Lite. 21,650 views is roughly a nickel per view for CLIO Lite and a calibrated mic. Reference this thread:

http://audioheritage.org/vbulletin/showthread.php?t=7351

Zilch
10-01-2005, 10:19 AM
If you are going to go to all this time and trouble you need to get set up with a decent hardware/software package. I'd suggest CLIO Lite. I'm about to spring for it, actually. I'm financing out of JBL Monitor Blue grille cloth sales. :p

I think I've demonstrated that a 1/3 octave RTA such as many members already have here can carry such investigations well beyond "casual." Here, it reveals that LE85/2420 is not quite so much the same, response-wise, as 2425/6/7 that I had supposed. I'll try a bunch of 'em here to confirm, as it's an issue Guido and others are wrestling with, as well. It looks like putting 8-Ohm aluminum diaphragms in 2425/6 does not give the same result as LE85/2420, but it may be a better one for certain applications.

You're right, though. Probably time for me to get more sophisticated about this....

Izzat LE14H-3 in your avatar? ;)

DRG
10-01-2005, 11:01 AM
I'm financing out of JBL Monitor Blue grille cloth sales. :pThat'll work.

Yes, the LE14H-3.

Zilch
10-01-2005, 11:26 AM
That'll work.Support the Zilchster's divinations! :thmbsup:

[Heh, heh....]

Mr. Widget
10-01-2005, 11:44 AM
I'll support you by buying a bit 'o the cloth... but, I want to finish some speakers first... might be awhile.:(


I'd love to see comparisons of several LE85s and several 2425/26s... but I can happily wait for you to get set up.;)


Widget

DRG
10-01-2005, 12:33 PM
Support the Zilchster's divinations! :thmbsup:I intend to.

Zilch
10-01-2005, 01:33 PM
Here's two 2426J's on the NL200t3-16 crossover, 2344A horn.

Then three LE85's under the same conditions.

The LE85's appear poorly matched; I couldn't make a pair out of this group. They are also different from 2426's. The second one is messed up in the 1 - 4 kHz region. They're all playin' 20 kHz well, tho.

So much for the "Preserve the red seals" thing. They should be opened, cleaned, the foam damping replaced as required, and retested. Maybe new aluminum diaphragms in them, too. :(

Somebody here said that. I confirm that they are right. ;)

On to some 2425J's now....

Mr. Widget
10-01-2005, 01:41 PM
I was suggesting this would be an interesting exercise once you had a Clio, MLSSA, or LEAP set up. Without time windowing, you are measuring the echos in your room as much as the drivers...

My take on the Red Wax... Sell them to the collectors at a premium and buy up the "tampered" ones and refurbish those... the profit you make off selling virgins will pay for new diaphragms, a bit of remagging, and cleaning them up...

I wonder if my ancestors were also into selling virgins?:hmm:


Widget

Zilch
10-01-2005, 02:43 PM
Four 2425J's under the same conditions.

The first pair came on a pair of rock 'n roll 2370A's. :p

Second pair came in the 4660's with the smoked crossovers.

Guess we know which pair gets the new aluminum diaphragms, now.... ;)

May I have more of the last one, please?

[It's gonna play mighty nicely on this crossover, I betcha.... :bouncy: ]

scott fitlin
10-01-2005, 02:49 PM
I wonder if my ancestors were also into selling virgins?:hmm:


WidgetI hear there is a tremendous market, and profit for virgins, but alas, they too, lose their value once their seals are broken!

:dont-know

Zilch
10-01-2005, 03:02 PM
Y'all can see it took all of 2.5 hours to do that.

The hard part was deciding to do it.... :p

[You CAN test yur drivers, folks, it ain't difficult.... :) ]

Zilch
10-02-2005, 01:56 PM
I've completed the second NL200t3-16 crossover and am playing the venerable vintage LE85's 1 & 3, above, on S3100 horns after EQ'ng flat with UltraCurve Pro. In spite of full HF boost, they sound smooth and natural. They have a bit more HF extension than 2425/6 to begin with.

I've invited Mr. Widget over for a listen, as he's particularly sensitive to, and critical of, the harshness of titanium diaphragms when the top end is pushed like this, which harshness seems to be gone. I'm wondering if the dusted titaniums will handle HF boost as gracefully now....

Here's what UltraCurve did to make them perfectly flat. These crossovers are really optimized for 2342/2344A horns; playing them on H3100 requires further correction (+/- 4.0 to 5.5 dB) as shown here. Dot is left channel, circle is right. AutoEQ'd separately, they virtually superimpose:

Zilch
10-02-2005, 03:19 PM
What is ( y ) scale please ??? 1.5 or 15 DB...That's 15 dB. You can see the corrections at the cursor for 6k3 Hz of -4.0 and -5.5 dB, respectively.

mmmmm titanium sound sweet ??? :blink:
good news.... :p
No, no. LE85 is vintage aluminum. See the title of the post. LE85 = 2420.

but diaphrams it is completely news or reclycling used ???Diaphragms are original. The red wax seals are intact on these.

it is possible to explain little bit more what is ultra curve pro works ???Behringer UltraCurve Pro 24/96, an inexpensive (>$300) combination RTA and digital equalizer, including an "Auto-equalization" function which will listen to the speakers and adjust the 1/3 octave equalization bands to make them play whatever response curve is specified.

UltraCurve is often ridiculed by the pros as a cheap knock-off of better tecnology, but there's a furtive underground cult here using them routinely.

Me, I use it for research.... ;)

Zilch
10-09-2005, 06:24 PM
Up from the dungeon, 4507 "Utility" enclosures come with 2226H installed as 4647A. With 1" thick MDF front baffle and cross-braced with 2x4's (see pic), they're about the same size as L200, but with more internal volume (5 cuft.) as the front baffle is only recessed 1/2" and not sloped.

Closing two of the four 2-7/8" dia. X 6-1/4" ports in each will retune them from 40 Hz to 28 Hz. Closing just one in each will bring them to 4430 standard 34 Hz tuning. They'll be getting 2235H's installed, and maybe PT waveguides or 2342's cut in (inverted). 2344A's won't fit in the baffle; there's only 11-1/4" below the woofer cutout there. Everest horns are merely for "illustration." :p

Ref: http://audioheritage.org/vbulletin/showthread.php?t=7480

Compare to the current version Citation 7.4-based Mini-Everests, middle.

[Dwarfdom. ;) ]

Available unassisted 2235H bass tuning options, bottom. Two ports open = blue, three open = red, and four open = black. There's unexploited versatility in these humble boxes....

DavidF
10-10-2005, 10:20 AM
Zilch, there is an old Laurel & Hardy short film where the boys go to sea to get Hardy away from the job. It seems the ole boy goes into a rage whenever he hears a horn. A condition prompted by his constant immersion in sound at his job in a horn factory. Hmmm...

DavidF

Mr. Widget
10-10-2005, 10:25 AM
Zilch, there is an old Laurel & Hardy short film where...


:applaud: :rotfl: :applaud:

Zilch
10-10-2005, 11:09 AM
You can see that the Everest horns are a "challenge."

From the results with H2600/H3100, tho, I'm now committed to giving them a good listen with proper EQ.

Cudos to the Everest builders here. I ain't up to the task. :no:

[Maybe out in the yard.... :p ]

Zilch
10-12-2005, 03:23 PM
I am nothing if not determined to play these beasts.... ;)

Dollys aren't good for bass response, but they let me finesse the orientation easily.

$38 at Grainger....

Zilch
10-13-2005, 11:12 AM
Some interesting additional information regarding Everest/Mini-Everest/S2600/S3100 appears over in the "Test Ride" thread, beginning here:

http://audioheritage.org/vbulletin/showthread.php?t=6373&page=2&p=70936

Zilch
10-16-2005, 02:43 PM
Newly acquired 2420 pair ($200) with tangential surround aluminum diaphragms on 2344A horns play nicely with LE14H-3 in Citation 7.4 boxes, DIY NL200t3-16 crossovers.

Clean, clear, crisp, more keepers here!

[Infredible made me do it.... :p ]

Zilch
10-17-2005, 10:37 AM
For those unfamiliar, here's what 4430's are all about, technically speaking, that is:

http://audioheritage.org/vbulletin/showthread.php?t=7551

Uncle Paul
10-20-2005, 05:40 PM
Can anybody explain the LF section of the NL200t3? It looks suspiciously like a second order Butterworth... but the 20 uF cap and 3 mF inductor would give an Fc closer to 600 Hz than 1200 Hz.

Zilch
10-20-2005, 06:41 PM
Yup.

http://audioheritage.org/vbulletin/showthread.php?p=49858&#post49858

They intersect at about 1.1kHz.

LF gotta be rolled off lower 'cause the HF is one pole and is playing lower.

Gotta read the driver AND the horn response to see what's happening there.

See HF RTA curves two posts above that one.

Also: http://audioheritage.org/vbulletin/showthread.php?t=3838&page=24&p=49973

That'd be MY guess.... ;)

Uncle Paul
10-20-2005, 07:13 PM
Thanks, that was driving me crazy, as well as the apparant Fc of the high pass section at 12000 Hz, too. One half as much, the other ten times the other way. The graph helps.

DavidF
10-20-2005, 08:12 PM
Can anybody explain the LF section of the NL200t3? It looks suspiciously like a second order Butterworth... but the 20 uF cap and 3 mF inductor would give an Fc closer to 600 Hz than 1200 Hz.

Can’t say for sure that this is the specific answer here, but you can tune the components for a desired effect. You could use a higher value inductor to start a roll off at some frequency below the desired xover point. The roll off combined with rising woofer response and/or impedance will net a shallower roll off than expected in a first order xover. The intent here may be to compensate for the diffracting effect of woofers response going down from about 1,000 cycles. This would be needed if the systems are expected to be used away from walls, etc. Then use a value of the shunt cap to effect the “knee” of the xover roll off. Helps here if there is some natural roll off in the woofer near by to complete the effect.



Looks like the high end is similar but in a different direction. The typical response of the horn approximates flat up to a certain point then droops at some frequency up to where it falls off sharply. Since you want the horn in a 2-way to cover the high treble regions flat (or better with some slight fall off) you can use the efficiency in the midrange band to your advantage. The low value cap on the high xover will pass frequencies over a higher than expected frequency. Say you target 15,000 cycles where everything above is passed, everything below is attenuated. Now the electrical effect of the cap is attenuating the response as it falls below somewhat above 15,000 cycles and, according to design, this falling electrical response will negate the rising acoustic response as you move down in frequency. The result will be a flatter response from the mids through the highs. The shunt coil with its high resistance value is probably used to tame a resonance in the low end response of the horn/driver. The natural tweeter's low end roll on is used to compliment the woofers high end roll off to complete the expected xover point somewhere around 1,100 cycles.


Simple and effective, probably not advisable for high volume applications to protect the horn driver and keep distortion levels down.

Suggested reading. Could be helpful in thinking through the xover design process where its not all textbook results.

http://www.pispeakers.com/Speaker_Crossover.doc


David F

Zilch
10-20-2005, 09:11 PM
It's confusing, perhaps, but consider the following:

1) The HF curve location is a function of the HF driver impedance. Note in the second curve posted by Giskard cited above, it shifted rightward ~2 kHz as he changed the impedance from 8 Ohms nominal to 3.5 Ohms actual for 2425H. We have to measure or otherwise know the impedance of the HF driver for the curve to be accurate.

2) Where the voltage drive curves cross is not the crossover frequency. The HF curve must be raised by the difference betwen the sensitivities of the HF driver and the woofer, and their response characteristics at the frequencies of interest, to approximate the system crossover performance.

John W wanted to know if using the LF section from 4425 would yield a better result than the "standard" NL200t3 when using a 2214H woofer in his project:

http://audioheritage.org/vbulletin/showthread.php?t=7110

Here's the two LF curves shown with a 4-Ohm HF impedance. It'll be interesting to see how his speakers actually measure:

John W
10-21-2005, 08:04 AM
Thanks, thats clear illustration of the affect the extra inductance has. I am working on a measurement setup and will post any meaningful data that I can.

Zilch
10-21-2005, 01:29 PM
For more options, I added 4430's 2.6 mH, 12 uF.

Orchid = 4430 2.6 mH, 12 uF
Yellow = 4425 3.8 mH, 14 uF
Green = NL200t3 3.0 mH, 20 uF

Choose LF as required for optimum system performance upon testing....

Ian Mackenzie
10-21-2005, 11:07 PM
Zilch,

This is becoming a very long thread!

There is some very good reference stuff in places but it takes a lot of time to find specifics.

Would it be possible to edit the reference stuff like the schematics and the measurements and partition them in a project thread or what ever?

I am just wondering what is your agenda at this stage?

Zilch
10-22-2005, 12:06 AM
Hi, Ian!

Actually, I'm working on a summary which includes direct links to the references. While there's lots of material here, it condenses nicely into just a few major related themes. I'll likely submit that summary as a separate "project" thread.

I'm almost done adding new material, I promise. We've got 2342's coming in, 2352's to look at, and the 2346's, of course. Also, E140's reconed to 2235H's are going in the 4507 boxes as another alternative LF component, as several members apparently have these.

The study of 1-3/4" diaphragm variants on alnico versus ferrite 1" motors will likely end up in a separate thread, like we did with ring radiators and compression drivers earlier. That's a subject of more general interest.

Several members are building systems according to the guidelines developed in this thread. I'm encouraging them to post their results here so they are contiguous with the source material rather than scattered in the archives. I may be reconfiguring an Olympus pair myself, as well.

Yes, the thread is long, but the summary will facilitate accessing the information and, I hope, bring new clarity to the endeavors documented here. In the meantime, readers might avail themselves of the utility of "Search" within the thread, available just above on each page.

I've read it through a couple of times recently. It takes me about half a day each time to do it, but it DOES make sense when viewed comprehensively. I'll make that a simpler task here shortly. No mystery, it's all about building two-ways based upon the 4430 formula.

Let me try this approach first. If it's still too unwieldy, I'll be willing to put some effort into reconfiguring it entirely in a project forum, assuming it deserves such standing....

Zilch
10-26-2005, 08:50 PM
No mystery, it's all about building two-ways based upon the 4430 formula.Hotrod "Bookshelf" 100° x 100° waveguide implementation here:

http://audioheritage.org/vbulletin/showthread.php?t=7671

O.K., O.K., itza 2.1-way, then.... :p

Zilch
10-28-2005, 04:44 PM
1) Alleged "Mid-format" 2352 Optimized Aperture Biradial horn (right) is nearly as large as Everest/2346. Both dwarf 2344A (front).

http://www.jblpro.com/pages/pub/components/23525354.pdf

2) Looking like a bug on a tricycle, 2435HPL neodymium driver (3" diaphragm, 1.5" exit) will play lower on these horns, which are good down to 500 Hz. Maybe I try 800 Hz for starters.

Can 243x drivers operate well with OA horns? They seem to meet the design criteria:

http://www.jblpro.com/pub/technote/tn_v1n21.pdf

3) Both horns and and 2509A brackets (not easy) had to be drilled for smaller-diameter mounting circle of 243x drivers. A rubber grommet reduces the bracket's 2" center hole down to the requisite 1.5". Rapid horn flare precludes reversing the bracket for more compact footprint. :(

4) RTA on 1 kHz AM crossover. Clearly, the HF compensation is wrong, but the response is there.

How do they sound? Well, kinda like everything else around here, ummm, "crispy." Tightly controlled 90° x 50° directivity. I'm goin' out on a limb and sayin' the midrange is cleaner than on the smaller waveguides, initial impression. We'll see after I get the compensation worked out better.... :p

Edit:

5) Better. ;)

Zilch
10-30-2005, 04:56 PM
2509A brackets in the E-Tent sale for $104, free shipping:

http://www.jblpro.com/Tent_Sale/index.htm

2510 at $65 will work with 243x drivers, too, but it's notches instead of holes for mounting....

jbljfan
10-30-2005, 05:47 PM
But when you need them, you need them. Thanks for the pointer. Is "better" (compensated?) still crispy?
Regards,
Mike


2509A brackets in the E-Tent sale for $104, free shipping:

http://www.jblpro.com/Tent_Sale/index.htm

2510 at $65 will work with 243x drivers, too, but it's notches instead of holes for mounting....

Zilch
10-30-2005, 06:32 PM
Is "better" (compensated?) still crispy?Hiya, Mike,

Yup, "Better" was still crispy, but not overly so. Johnaec heard them yesterday (along with the amazing little Hotrods,) and deemed them "Fine."

I did a little more today, and got them within +/- 1.25 dB. Don't know what's going on down there at 2 kHz; gonna have to take impedance measurements for a clue.

This is all passive, so I can't "boost" anything to fix that. Gotta figure it out, is all. Put the slope I want in 'em, too.

I think I'm about done compensating until the 2235H recones get back here to install in the 4507 boxes. That's what these are gonna mate with, to become MEGA 4430's! :p

[No, NO, I ain't doin' 2360's. Nope....]

Rudy Kleimann
10-30-2005, 08:49 PM
2509A brackets in the E-Tent sale for $104, free shipping:

http://www.jblpro.com/Tent_Sale/index.htm

2510 at $65 will work with 243x drivers, too, but it's notches instead of holes for mounting....

The 2510 does not include a yoke to mount to the top of the cabinet like the 2509A, nor does it provide any means to swivel the driver and horn up down, or side-to-side. It is really meant to be used as a "flypoint" mount to hang the horn and driver in the air on cables or chains.

The 2509A mount is pricey, but it does the job right.

Zilch
11-01-2005, 10:16 AM
Dutchman found some 4430 clones: http://audioheritage.org/vbulletin/showthread.php?t=7795

DRG
11-08-2005, 01:41 PM
1) Take B380 w/2235H set vertically on "foot"
2) Mount 2344A w/2426H/J on top
3) Cross @ 1 kHz w/CD compensation (M552)
4) Biamp

Something I'm missing here?I really wish Keele, Eargle, and Smith would respond...

Robh3606
11-08-2005, 02:07 PM
"I really wish Keele, Eargle, and Smith would respond..."

Well they already have in a way. Look here.

http://audioheritage.csdco.com/vbulletin/showthread.php?p=76021#post76021


Rob:)

DRG
11-09-2005, 07:00 AM
Thank you very much David and Don. ;)

http://www.audioheritage.org/html/profiles/jbl/4430-35.htm

Zilch
11-09-2005, 10:50 AM
Thank you very much David and Don. ;)

http://www.audioheritage.org/html/profiles/jbl/4430-35.htmWOO HOO! The "Magic" is revealed. :thmbsup:

A HUGE thank you, with utmost sincerity....

Ian Mackenzie
11-09-2005, 11:29 AM
Zilch,

One of our members posted details of a 4 way using as I recall a 2245, a 2202, the 2344 and the 2404.

I think it would be useful and interesting to look at the angle of a 2 1/2 way and start subjective comparisons of such.The 2 way horn system might be a worthy compromise for SR but we are talking home audio here for the most part...

You can't make a silk purse out of a sour's ear....and there are now recordings and media (SACD, DVD Audio) that command superior perfomance from home entertainment equipment.

Despite the response appearing relatively flat to 18-20 khertz of your 2 way horn incarnations, they don't sound that way compared to dedicated devices covering 10khertz +.

There are sound mechanical reasons and laws of physics that prevails over why this is the case. Hence we see examples like the latest Array Series using a uhf device.

Your investigations are appreciated.

Ian

Zilch
11-09-2005, 01:06 PM
Despite the response appearing relatively flat to 18-20 khertz of your 2 way horn incarnations, they don't sound that way compared to dedicated devices covering 10khertz +.I acknowledge that JBL has thus far chosen not to exploit the apparent HF extension capabilities of these combinations in two-way designs, but note for the record that they DO, in fact, use some of them as tweeters.

It ain't as if we can actually hear up there, in any case. The real struggle insofar as the sonic quality is concerned is to get optimum smoothness between 8 kHz and 16 kHz, in which respect we have found that pushing 20 kHz for its own sake may indeed be counterproductive.

2435HPL, for example, is allegedly pistonic to 17.5 kHz. Frankly, it sounds better if I don't force the response beyond that into breakup mode. Just a theory, that seems to mess with what is DOES do well, so, to what end? An RTA display?

Again, I find the Cinema systems white paper quite illuminating with respect to HT applications and the HF extension issue:

http://www.jblpro.com/pub/cinema/cinedsgn.pdf

The other major compromise is between 500 Hz and 1 kHz, though I have not yet come upon means to analyze that. There may be better LF driver choices than 2235H. As you know, I and others are working with LE14H-3. See Project Array, for example. We'll get there.... :)

Mr. Widget
11-09-2005, 01:15 PM
I acknowledge that JBL has thus far chosen not to exploit the apparent HF extension capabilities of these combinations in two-way designs... I am sure they have tried... the fact that they may have done this or that back then and don't now isn't because they are now lame or being driven entirely by market forces... through the use of their new R&D facilities they are now making some of the best systems that they have ever been able to produce.


... but note for the record that they DO, in fact, use some of them as tweeters.I think you are confusing PA applications with Hi-Fi and monitoring applications.


Widget

Zilch
11-09-2005, 01:21 PM
I believe Mr. Widget would agree, however that getting what we CAN actually hear correct is job #1.... ;)

Lancer
11-09-2005, 01:23 PM
I think it's time you had a conversation or two with Doug Button Zilch...
While fun, two-ways are nothing more than two-ways.


I believe Mr. Widget would agree, however that getting what we CAN actually hear correct is job #1.... ;)An LE8T-H can handle that requirement. ;)

Zilch
11-09-2005, 01:27 PM
I think it's time you had a conversation or two with Doug Button Zilch...PM me the contact info, please, and the particular issue(s) to discuss.

I'm good at technical outreach.... ;)


An LE8T-H can handle that requirement.Gotta keep the voice coil in the gap, alas.

PLUS, it has no "sizzle."

[Needs a tweeter.... :p ]

Lancer
11-09-2005, 01:31 PM
PM me the contact info, please, and the particular issue(s) to discuss.

I'm good at technical outreach.... ;)

Gotta keep the voice coil in the gap, alas....The particular issues would be everything he could teach you about compression drivers in the limited time he has. He reads the forum. He'll contact you if he wishes. In the meantime, you might want to pour over anything you can find written by Fancher Murray. You're doing good stuff here. Get some input from other sources. No one here is helping you with the back end.

Mr. Widget
11-09-2005, 01:31 PM
I believe Mr. Widget would agree, however that getting what we CAN actually hear correct is job #1.... ;)I guess you are talking about the crazy >20KHz specifications... that is most certainly NOT what I am talking about.


Widget

Ian Mackenzie
11-09-2005, 01:34 PM
It ain't as if we can actually hear up there, in any case.

Its the accurate reproduction of those overtones that true audio reproduction lives and dies by.

The real struggle insofar as the sonic quality is concerned is to get optimum smoothness between 8 kHz and 16 kHz, in which respect we may have found that pushing 20 kHz for its own sake is indeed counterproductive.

The reality is that other factors are considered equal if not more important than nice re touched / eq'd curves. If its not meant to work up there why force it.

:)

Zilch I was perhaps expecting a response a little more outside the square.

Many including most sound recording engineers and JBL would tend to disagree on your statement.

JBL's own consumer literature clearly points to and explains the pertinent facts.

Zilch
11-09-2005, 01:34 PM
I guess you are talking about the crazy >20KHz specifications... that is most certainly NOT what I am talking about.'Zactly....


Are you kidding?Let's you and them fight.

[Heh, heh.... :D ]

Lancer
11-09-2005, 01:35 PM
Gotta keep the voice coil in the gap, alas.Ain't that the freakin' truth! :rotfl:
PLUS, it has no "sizzle."That's why the DIY's added in the 077's. :p

Robh3606
11-09-2005, 03:49 PM
Well I have to chime into this one. Most 2 ways are compromised at both or at least one end of the spectrum. The 4430 is decidedly not compromised on the lowend however up top above 10K there is no question there is room for improvement. I won't get into the midrange aspects of this and just leave it at that. Take a look at the distortion curves and you can see just how hard your are pushing the 1" driver. Sure there is output there however it's not as clean as a dedicated UHF driver. We all know that adding a UHF driver has it's own set of issues and will add rippples to the response. So again it's name your poison. Either you have elevated distortion levels or ripple in the passband. Which one is better???

Personal choice.

The funny thing is I still like the 2344 better overall, warts and all, than the top end on the 4344 even though I know the 4344 in more accurate. I could easilly live with either if I had to make the choice. They are both excellent solutions to the same problem.

Rob:)

Zilch
11-09-2005, 04:39 PM
Take a look at the distortion curves and you can see just how hard your are pushing the 1" driver. Sure there is output there however it's not as clean as a dedicated UHF driver. We all know that adding a UHF driver has it's own set of issues and will add rippples to the response. So again it's name your poison. Either you have elevated distortion levels or ripple in the passband. Which one is better???Clearly, we need to do some work measuring distortion of the 1.5" drivers on the various horns and waveguides under evaluation. I suspect, just by the physics of it, that the improvement to which you allude is achievable, and more HF extension (particularly with 2431H), as well....


The funny thing is I still like the 2344 better overall, warts and all, than the top end on the 4344 even though I know the 4344 in more accurate.We agree. The 2344 is damn good. It's part of the 4430's "Magic" I frequently cite, and the standard against which any and all alternatives are compared here.

On the occasion when I supplemented it with 2404, the only apparent benefit was that I could dial in more VHF than the 4430 was alone providing, i.e., more than needed or desired.

Is the fact that we like the VHF better a bit rolled off indicative of it being of poor quality? I don't think so. The favor that contour enjoys is just too universal, and independent of the driver complement....

Ian Mackenzie
11-11-2005, 04:47 PM
http://www.audioheritage.org/html/profiles/jbl/4430-35.htm

Possibly all that anyone needs to know about a 4430-4435 is right here.

David Smith is quite a remarkable engineer.

Zilch
11-19-2005, 04:45 PM
O.K., first try with 275nd diaphragms on 2426H motors, here with 2342 horns, LE14A woofers.

It does not appear that these will work as drop-in replacements in most systems without crossover modifications. I tried various horn/crossover combinations to get this with AM6212 HF and NL200t3 LF for a listen without EQ. They still need help around 5 kHz.

Compare impedance curve on 2342 to Giskard's run with standard 2425H on 2344A here:

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=27&p=53994

I'm not seeing anything anomalous.

Mellow and smooth, aquaplas coating on this thinner titanium diaphragm mitigates the characteristic harshness, even with full HF extension.

Also tried them on 2344A with 4430's N3134 crossover (bottom). Can't dial them flat. I don't think it's an alignment issue, since both drivers behave similarly.

More once we complete the 1" driver/diaphragm study here....

Ian Mackenzie
11-19-2005, 08:50 PM
Try doing an impedance sweep or check your fixed resister crossover values.

There way too much attenuation at 4 khz but the other section seems to work okay.

What was the last diaphragm impedance you used ..16 ohms?

Zilch
11-19-2005, 10:55 PM
Thanks, Ian.

I did the impedance sweep and added it to the post above.

Also did an audio sweep to be sure there was no buzz/rub from installer error.

I don't have a 16-Ohm version of the crossovers I'm using here, so it's not that.

It looks like the 2426H driver characteristics are sufficiently altered with installation of D8R275ND as to require different compensation, is all.

In a former life, I'd be dismayed.

CLIO will tell us what to do.... ;)

Ian Mackenzie
11-19-2005, 11:05 PM
Odd,

Okay I get it.

I found the curves below on my HD for comparison.

Your orange impedance curve looks almost identifical to the 2426 + Dr82425.

Maybe the rear chamber of the 275nd is larger...or what ever?

Zilch
11-20-2005, 01:25 AM
Maybe the rear chamber of the 275nd is larger...or what ever?I don't know. I'm not certain the dome radius is the same, even, though I have no reason suspect otherwise. The phase plug may be different, as well:

http://www.lansingheritage.org/images/jbl/specs/home-speakers/1993-k2-s5500/page09.jpg

Aquaplassed diaphragms seem to be a "Now you see it, now you don't" phenomenon. I notice that JBL's using it on the 3" diaphragm 435AL-1 (2431H type) driver in Project Array.

Are there any stock 1-3/4" aquaplas-dusted diaphragms other than 275nd to try in 2425/6?

Zilch
11-27-2005, 04:36 PM
[At least for today.... :p ]

N3100 crossovers constructed to run the Mini-Everests, completed yesterday. Anybody know (or guess) the function of the initial LCR filter with the fuse in the HF? Why?

I modeled it in Spice, and it does nothing that I can discern:

http://manuals.harman.com/JBL/HOM/Technical%20Sheet/S3100%20ts.pdf

Here they are running the Everest horns with 2426H and B380's for LF. Getting the aiming correct for the "locked image" effect is more critical and difficult with these big horns than H3100. I'm not sure I've gotten it right yet. RTA shows rolled off high end, but it's not apparent in the way they sound: clean, crisp, bright with solid midrange. Crossed at 750 Hz.

H3100's produce a similar curve with a bit more HF SPL (~2.5dB) and steeper rolloff (second RTA pic). I'd pad 'em down except they sound just fine as they are.

Zilch
11-27-2005, 09:43 PM
Similarly configured 2352 horns with factory refurbished 2435HPL drivers. We still don't know if the combination is "correct" from a design perspective (Optimized Aperture horn playin' later two-stage phase plug design neodymium drivers), but they certainly measure and sound good together. Crossover derived from AM6212/00 provides about the flattest HF curve I've ever achieved without AutoEQ here.... :D

CLIO is in the mail, folks, thanks to a lead from forum member Ian Mackenzie....

grumpy
11-28-2005, 08:37 AM
Anybody know (or guess) the function of the initial LCR filter with the fuse in the HF? Why?

I modeled it in Spice, and it does nothing that I can discern:

Run Spice looking at the network impedance instead of the output voltage. Should see
a difference ~2.3KHz (lower) unless I dropped a digit somewhere. :D

-grumpy

Zilch
11-28-2005, 10:03 AM
Run Spice looking at the network impedance instead of the output voltage. Should see a difference ~2.3KHz (lower) unless I dropped a digit somewhere. :D The impedance, huh? I've never had occasion to run a network on WT2. This could be the opportunity.

[Gotta figure out how to make Spice show impedance, too.... :p ]

EDIT: Here's the WT2 impedance (red) and phase plot of HF network, driver, and horn, without that filter.

ACK! (I think ;) ). I'll scrounge up the parts to see the difference. :)

Zilch
11-28-2005, 05:29 PM
On 2342 (4425) horns using NL200t3 crossovers with LE14H-3 in Citation 7.4 LF:

1) 2407H - Yikes! Oh, yeah. It's a TWEETER, silly! (-5 dB)

2) 2416H-1 - Used in I don't know what, I just HAVE 'em.

3) 2418H-1 - JBL's cheapest compression driver.

4) 2426H - Ummm, y'all know this one.

5) 2426H/275nd - With aquaplassed diaphragm.

Zilch
11-28-2005, 05:33 PM
Last two using the "-16" version of the crossover HF:

6) 2426J - Same deal, plenty available.

7) LE85 - With throat adapter.

Which driver would YOU be playing with 'em 2342's right now?

"This ain't no party,
This ain't no disco,
This ain't no foolin' around...."




[Note: 2342 horns still available new from JBL Pro Parts. :thmbsup:]

Earl K
11-28-2005, 07:06 PM
Hi Zilch

I always enjoy this thread a lot / thanks for keeping it going :)


Anybody know (or guess) the function of the initial LCR filter with the fuse in the HF? Why?

- I'll hazard a guess that the fuse is present because the circuit designer was concerned about the safety of the overall circuit ( & source amp ) due to relatively high voltages developing across both the inductor & capacitor .

- These developed voltages are the product of the LCR "Q" multiplied by the applied voltage . ( Perhaps he thought the capacitor might create a dead short and in turn present this short as a parallel load to the driving amplifier . )


- The "Q" of the series LCR circuit will determine how much voltage is developed . For instance; if the applied voltage measures 2 volts across the inline resistor ( of the LCR ) and the resonant circuit has a "Q" of 40 , then the measured voltage across either the capacitor or the inductor should be 80 volts . Conversely, one can get an idea of the "Q" of that "series resonant trap" by measuring the voltage across that same resistor and then measuring the voltage across either the inductor or capacitor . Dividing E(resistor) into E(inductor) should equate to the "Q" of the resonant circuit .

BTW:
- This info is taken straight out of "Electronics Math" by Alan Andrews , a Sams Publication ( # 21152 ),,,pages 168 - 170/ I may have relayed some of this incorrectly since I haven't yet done any hands-on bench testing / to correlate real-world results to the theory .

- I've included some LCR info for you to ponder ( the basis for the chart is Giskards' info lifted from the May project ) . You can see by the determined resonance values that both the N3100 and the N9800 ( there are some other examples ) each use a couple of series LCR(s) which are electrically located within octave fractions of each other. In both circuits they have some isolation from each other provided by the inline ( padding or series ) resistor ( 7.5 ohms & 16.5 ohms respectively for the N3100 & the N9800 ) .

EDIT: The following statement would seem to be contrary to the additional information provided in the following posts
- The speculation is that the higher "Q" LCR is always positioned closer to the source with the lower "Q" LCR(s) placed closer to the load ( when both occur in the same circuit ). I don't know enough about the pratical implementation of these "resonant traps" to take it much further / though I do use some kludged together "resonant traps" with my biamped Altec 288s .

Cheers :D

Zilch
11-28-2005, 11:18 PM
Thanks Grumpy and Earl. So, we apparently have a notch filter @ 2.3 kHz. Being a resonant circuit, if the driver were to become disconnected, or some other failure occur, the impedance could drop to zero with the oscillation. Thus, we have doubled shunt resistors and a fuse to protect the amplifier against such an occurance. The fuse would blow with a sustained 22.5 watt dump to common.

Note that S2600 uses a similar notch, with 20 uF instead of 30 uF. S3100MKII doesn't use it.

I do see a little peak at 2.3 kHz in the RTA curve for H3100 above, which was being driven without the notch filter. I also ran a painfully long 500-point impedance curve on the driver and horn from 500 Hz to 10 kHz. If there's a major resonance peak at that frequency, it's not apparent. Perhaps there was more of a problem before they started coating the rear of the horns with Aquaplas:

ndnorth
11-29-2005, 06:52 AM
I was looking at the 3100 network and found the front string of components a little curious. Hanging at the front of the network it can't effect the system response as long as the driving impedance is low (any modern amp and reasonable lead resistance.) Modeling the network will show NO difference to the volts at the driver terminals unless a few ohms are modeled into the amplifier source Z. The clue here is that the resistor (R5 parallel to R6) is 10 ohms. This makes it less a notch and more of a conjugate circuit as a conjugate generally has a resistor equal to the impedance value you are "flattening out to". I suspect that the overal system impedance curve went very high at 2300Hz (calculated center frequency) and the designer wanted to flatten it out some. The fuse doesn't protect the driver, if it blows the conjugate goes away but the driver still sees the rest of the network. Also note that, unless biamped, this circuit is at the input to the whole system and works to flatten the whole system impedance.

A second thing to note is the notch filter at the back side of the circuit. (C9 L2) It is also tuned to about the same frequency (2500 Hz) and WILL put a dip into the driver response. What they don't tell you is that the inductor probably has a significant resistance built into it. Otherwise it would be very narrow in effect and damaging to the impedance curve. I would model it with a range of resistances (say 1 to 4 ohms) and see what the effect is on the response curve.

Finally, the network is basically second order. The R3 C5 combination is an EQ feature common to all the constant directivity horn networks. R3 sets the midrange level and the C5 bypass lets the highs around it. Raising or lowering R3 would lower or raise midrange level. Reducing C5 would raise the bypass frequency and reduce the lower treble.

Regards,
David

DRG
11-29-2005, 06:54 AM
Thanks David! :)

Also note that, unless biamped, this circuit is at the input to the whole system and works to flatten the whole system impedance.

Thank you for explaining this. It seems G.T. has been doing it alot lately in his filters. "Lately" is relative, I think it's been close to 15 years now. :dont-know

Here's a very recent example. Notice the lack of notch filters compared to other recent JBL designs.

Earl K
11-29-2005, 07:17 AM
Yes,

Thankyou both , David & DRG for the valuable insight .

:)

grumpy
11-29-2005, 09:13 AM
FWIW,

1) Network transfer function (assume lossy L2), vert = dB
2) Network input impedance w/ series LCR, vert = ohms
3) Network input impedance w/o series LCR, vert = ohms

-grumpy

Zilch
11-29-2005, 10:50 AM
1) Network transfer function (assume lossy L2), vert = dB
2) Network input impedance w/ series LCR, vert = ohms
3) Network input impedance w/o series LCR, vert = ohmsWell, there it is, then. I ordered the additional parts yesterday.... :thmbsup:


A second thing to note is the notch filter at the back side of the circuit. (C9 L2) It is also tuned to about the same frequency (2500 Hz) and WILL put a dip into the driver response. What they don't tell you is that the inductor probably has a significant resistance built into it. Otherwise it would be very narrow in effect and damaging to the impedance curve. I would model it with a range of resistances (say 1 to 4 ohms) and see what the effect is on the response curve.Yes. I used 7.5 Ohms total (7.0 plus 0.5 for the inductor) in the circuit construction based upon earlier suggestions here and prior experience with NL200t3. It produced a "familiar" voltage drive, and made a good starting point, from the RTA results.

Thank you for your insight into the circuit design. We can tweak with more assurance, now.... :D

Zilch
11-29-2005, 11:17 AM
Here's a very recent example. Notice the lack of notch filters compared to other recent JBL designs.May we see the entire network, please?

We enjoy analyzing them, quite apparently.

[Hoping it's a TWO-way.... ;) ]

DRG
11-29-2005, 11:35 AM
It's from a three-way design. I thought it was interesting to note that the impedance leveling circuits were still being used. I would draw up the full schematic and post it but I think the tech sheet will be available soon.

Zilch
11-29-2005, 11:49 AM
I would draw up the full schematic and post it but I think the tech sheet will be available soon.Thanks, DRG. Let us know with link, when available, please....

ndnorth
11-29-2005, 12:18 PM
Hi Zilch,

Good agreement between your simulation and Grumpy's. By the way, what are the two R values for the two different notches that you show?

David

Guido
11-29-2005, 12:18 PM
Thanks Zilch! You made it work.....

I can't stand the feeling that we have input from "inside" now ;)

Zilch
11-29-2005, 12:28 PM
Hi Zilch,

Good agreement between your simulation and Grumpy's. By the way, what are the two R values for the two different notches that you show?No resistance for the deep notch, 7.5 Ohms total for the shallow one.

That step compensation occurs frequently, I've found, to let the driver/horn combination play through frequencies where their inherent response is flat, apparently, i.e., "Don't mess with the GOOD stuff...." ;)

It's more precisely achieved in S3100MKII with multiple notches:

http://audioheritage.org/vbulletin/showthread.php?p=67205&#post67205


Thanks Zilch! You made it work.....Only with the help and guidance of many on this forum, including yourself in significant measure, good friend! :thmbsup:

The problem with this thread is I've got about 20 pair of "Keepers" now.... :p

Lancer
11-29-2005, 01:05 PM
I can't stand the feeling that we have input from "inside" now ;) ;)