Quick & Dirty 4430-Inspired Two-Ways Part I

[Guido]

A minor glitch. Factory crossovers use 2.5 ohms for R1, not 4.0 Ohms. DUH!

By "Behind the LRC," I assume you mean between the LC and the LRC. No other location makes sense, actually, unless you're just doing attenuation on the output.

[I'd call that "Ahead," going from in to out. :p ]

R1 2.5 Ohms works even better. See pic. Blue=4 Ohms, Yellow=2.5 Ohms

NOPE, I meant just attenuation between the LRC and the driver! We need to attenuate the 2431 a bit so try a L-pad first.

[Guido]

To close the 1kHz gap please -in addition to check polarity issue- play with the value of L1 in the AM network.

4dB attenuation is already in that voltage drive!

Green=stock
Yellow=1.0mH
Blue=1,5mH

[Guido]

This 1kHz gap is weird.

Voltage drive of the 3134 and AM networks shows even more boost in the 1 kHz region for the AM. See pic.
Green=3134
Blue=AM

Should the 2431 be so much weaker in the 1kHz region?
Do we have measures of the 2426 and 2431 w/o any network to see their response?

[Zilch]

L4 spec = 0.08 mH. Actual units read 0.041, 0.041, so it was changed as well as the resistor. Call it 0.040, a likely selection.

L1 spec = 0.6 mH. Actual units read 0.583, 0.596. It was not altered, apparently.

Most of the 1 kHz notch is a phase issue, as you suggested. I'll post curves as soon as I get these crossovers back together tonight.

We don't have raw driver curves on 2431 or 2435 yet. Widget's doing Project May work, so it'll be a week or so before he has any time available, most likely. I wouldn't think 2431 would be weaker than 2426 at 1 kHz. Lower, like 800 Hz, maybe. We'll know soon....

[Zilch]

Left out of phase
Left in phase
Right out of phase
Right in phase

2.5 dB per dotted line.

I was playin' outta phase, because AM6212 did. Adding N3134 low filter reversed it. N3134 HF disconnected at C11; there's no interaction.

Note 2431 driver variability. It could be the horns, but I doubt it.
Edit: It's the drivers. I swapped waveguides.

Something in the room is eating 500 Hz pretty good.... :)
Seems to be other speakers. I short them out or move them out, 500 Hz comes back.

I agree with Guido now. N3134 low filter is very important. It has built-in room correction, apparently. The bass comes to life.

[3 dB/octave seems a little overwrought, tho.... :p ]

[Guido]

L4 spec = 0.08 mH. Actual units read 0.041, 0.041, so it was changed as well as the resistor. Call it 0.040, a likely selection.


Again not a minor change!

Green= 0.08mH
Yellow=0.04 mH

The green curve would suit our project better? Does it?

[Guido]

Note 2431 driver variability. It could be the horns, but I doubt it.
Edit: It's the drivers. I swapped waveguides.


Shame on them! This is far more then production varaition.
I should wait with buying the drivers until they installed a QM System :)

Maybe one is a 2430 and one is a 2431? Gluing wrong labels :p
2431 should have better HF extension as Giskard mentioned.

[Zilch]

I should wait with buying the drivers until they installed a QM System :)No, go ahead and get your drivers! They'll run nicely on your P-Audio horns for now. We need independent confirmation of what is "right" here, and whether it comprises a significant upgrade over the prior "standard." I am confident JBL will make good under warranty coverage, once confronted with the problem.

There's also the subjective side to this. I'm VERY interested to know how this combination "sounds" to others. If the HF extension is there, it's not being pushed nearly as hard as prior approaches, and it should be smoother, with reduced distortion. Also, if the Al diaphragm is behaving pistonically to higher frequencies as the Be one is alleged to do, the character of the sound should be much improved.

No more tweaks until we get driver curves completed, then. This sounds mighty good, as is. I doubt they'd have made these crossover changes from the published schematic unless they had production variables under control and a statistical basis for doing so. The changes seem to be a refinement that reduces the HF "push," which is good.

[I AM gonna add bypass capacitors to the crossovers, tho....]


Maybe one is a 2430 and one is a 2431?Maybe one of them is a 2435? :p

[Earl K]

Note 2431 driver variability. It could be the horns, but I doubt it.
Edit: It's the drivers. I swapped waveguides.

- just which of the pictures ( & in what post ) display the drivers FR variations ?

Thanks :cheers:

[Zilch]

Hi, Earl!

On the previous page, look at the HF extension in post #255, left vs. right driver. Right is the presumed "good" one. It shows in earlier posts as well and was mentioned there. I've seen it under enough conditions now to be satisfied the difference is real, i.e., not a room or measurement anomaly. And it's not the waveguide. I swapped those yesterday to check.

I have more drivers on order to determine how they "should" perform, but the one with less HF does poorly below 2.5 kHz, as well. I doubt that anyone without an RTA or substantially more discriminating hearing than me would know the difference, though.

Oddly, though, the pair of 2435's I have (bought off eBay, of obvious dubious history and lineage,) don't have that good HF extension, either, but they at least play well in the 1 - 2 kHz range.

[Earl K]

left vs. right driver

The posted images as seen from my browser, with this screen resolution , using this size monitor ;

- displays 4 images, in a vertical row / top to bottom /

ie
- there is no left to right for the ordering of the images. .

:cheers:

[Zilch]

Earl: Look at the beginning of that post where I listed what's shown. First two are left, and second two are right, each with phase reversal. See how they are performing at and just below 20 kHz?

Curiously, the "better" one was final tested in 2/04; the "defective" one, later, 5/04. We'll see....

[Earl K]

Got it ,,, Thanks ! :D

You know, I think my mild case of dyslexia prevents me from registering these things "the first time" . :(
Or else, I'm enjoying a "seniors moment". :blink:

:cheers:

[Guido]

Zilch, as I want to rebuilt the AM.. xovers, could you do me/us a favour and measure the DCRs of the inductors of the HP out of the circuit?

Oh and is the DCR of the 2431H really 4.4 ohms?

Would be GREAT :applaud:

[Zilch]

Stupidly, I unsoldered them for Mr. Widget to read the impedance, but neglected to measure the DCR. Been meaning to do that again, of course.... :banghead:

[I go do it now....]

Drivers: 2431 = 3.9, 4.0 Ohms, 2435 = 4.1, 3.8 Ohms

L1: 0.228, 0.225 Ohms

L4: 0.052, 0.050 Ohms

Measured at 400 mA DC, i.e., 90 and 20 mV drop, approx., respectively, with 10 Ohm precision source resistor dropping 4V

Both 0.375" square laminate core, 1.70" long, 20 AWG (.035" O.D. enameled)

I'm not finding equivalent air cores; somebody gonna have to help us out, here

R1 is 25 W

Caps are "No name" generic OEM mylar, looks like

No bypass caps

I installed 0.01 uF metalized polyester (mylar) bypass caps to no perceptible effect. Parts Express is B/O on their film & foil polypropylenes right now, alas....

We need to put together a parts list for building both sections, with complete specs and sources, so we all build much the same thing. Clearly, in doing that revision (2.5 Ohms, 0.040 mH), somebody said, "Oh Hell, just make it flat shelf...." :p

Don't know how they're gonna play together, either. I am biamped....

[Guido]

Thanks Zilch!



We need to put together a parts list for building both sections, with complete specs and sources, so we all build much the same thing. Clearly, in doing that revision (2.5 Ohms, 0.040 mH), somebody said, "Oh Hell, just make it flat shelf...." :p

Was it 2 Ohms or 2.5 ohms?

[Zilch]

Lemme check again....

2.5 Ohms, 25 Watts.

Got your drivers yet? :bouncy:

Mr. Widget came over for a listening session. He still likes "real" 4430's best here.

I'm the first to admit: when you mate 2344(A) on 2426H with N3134, something magical happens. It's tough to beat.

[Wish David Smith would tell us what.]

Widget's SO good at this, he could predict the RTA curves before the pink noise even came on. :D

[Who else would insist you get the left and right channels correct before listening further?]

I'm working on his suggestions now....

[Zilch]

Not to worry. Just comparison testing.

Tweeters permit grossly exaggerated sizzle, tho. :blink:

[Thankfully, UltraCurve takes it right back out.]

My primary interest is in assessing HF extension, but the virtues of two-way are immediately apparent. This is one muddy sounding 12 dB/octave crossover mess by comparison. 3110A and 3105, 2426J and 2404H-2 (2402 diaphragms).

Results: It augments 2426 without boosting it beyond normal CD compensation, is all, though it's nearly impossible to set correctly, even with RTA, since with cascaded crossovers, the 3110A CD "boost" is applied through the 3105 to the UHF as well. Do 2404H ring radiators want CD boost? ACK!!

Need 2405 diaphragms for it to actually DO anything more than 2431H, apparently.... :p

[Guido]

Hi Zilch,

we're still waiting for the response and impedanced curves of raw 2431 right?

I have ordered my 2431 but the didn't show up. Today I'll order the components for the AM HP network. Maybe I'll try biasing.

Could you please measure the necessary baffle cutout and position of mounting holes of the PT Waveguides?
I still hope to get the horns with your help :bouncy:

[Zilch]

We're still waiting for the response and impedance curves of raw 2431 right?Yes. As you know, one of my two units is not performing up to par. I have two more on order (along with your horns), and when I receive those, I'll take them all over to Mr. Widget for measuring so we can get some statistical indication of what they are (or should be).


Could you please measure the necessary baffle cutout and position of mounting holes of the PT Waveguides?While I have not yet mounted any, I do have the factory gaskets for them on order, which I would use as template for cutting the baffle opening.

The horns measure 12 x 12 inches, and the cutout needs to be 0.75" smaller all around, so 10.5" square, with 0.5" radius at the corners.

There are 3 mounting holes on each side, 12 total, all 0.375" in from the edge, one on the centerline, and the other two spaced 3.875" out in each direction.

They mount with #10-32 pan head screws according to the AM tech sheet. There is no boss, countersink or counterbore on the horns themselves, just flush on the face.

[I don't think I'd be cuttin' or drillin' anything until I actually had the horns in hand if I were you, tho....]


Today I'll order the components for the AM HP network.PM me your list with vendors, specs, and part numbers, so we can put together a preliminary parts list to post here, please. Are you using air-core inductors? Are they custom? N/A from Parts Express, for example.

[Guido]

PM me your list with vendors, specs, and part numbers, so we can put together a preliminary parts list to post here, please. Are you using air-core inductors? Are they custom? N/A from Parts Express, for example.

I do order everything at intertechnik, a german company where I have dealer conditions. Therefore it makes no sense to put their parts on the list as you do not have an importer in USA.
Caps:
I'll use MKP (metalized pp) Caps. Bypassed with Polyester and PP Film/Foil caps.
As I bypass I'll use 2 pcs 12uF for C2 and 2 pcs 3.3uF for C1.
Inductors:
I'll use air core types. 0.04mH, 0,15ohms as L4 and 0.56mH, 0,23 ohms as L1

I'll add also a L-Pad for adjustment of the overall sensitivity

2.2 mOhm 0,25W Resistors for the bias voltage (9V)

[Zilch]

If I run 8-Ohm 2431H on a 16-Ohm crossover like 3110A or 3120A with an 8-Ohm non-inductive resistor in series with the driver to make the impedance correct for the high pass, is there any significant consequence other than the 6 dB attenuation (which we need, anyway)?

I don't think we give a whit about damping factor at these frequencies, right?

[This works, by the way. More on it later, after measurements....]

[Zilch]

Our earliest measurements of an all-original LE85 here compared to a pair of 2426J's showed it had a smidgeon more HF extension than those newer design drivers. We also have seen many users assert that the older aluminum-diaphragm LE85 is somewhat smoother and warmer sounding than the titanium 2426, which allegedly has an element of "harshness" by comparison. We wanted to use LE85 in our L200 upgrade, if possible, since it comes with the package.

On initial examination, we doubted that the deep-throated LE85 would play well on the new Progressive Transition (PT) waveguides, especially with two intervening throat adapters required to make the connection. Not so, apparently. The two engineered diffraction constrictions, one in the throat adapter and one in the waveguide itself, seem to allow it to work just fine.

This affords an opportunity to upgrade L200B to constant directivity at little expense. A major feature of 4430's (which, notably, used the pro version of LE85 in their initial iteration,) is their uniformly controlled dispersion of mid- and high-frequencies over a 100° x 100° sound field provided via the trademark 2344(A) "butt-cheek" Biradial horns. The character of the listening experience is very different from that of systems using exponential horns with lenses and "focused" UHF drivers. While there is still a "sweet" spot with 4430's, it is broader and more diffuse both horizontally and vertically than provided with these other systems. The literature also highlights constant directivity's enhanced reverberant field as more like "live" musical performance.

For those who strive to achieve audio nirvana with speaker systems behaving as room-sized "headphones" reproducing and beaming the source material to the listener precisely as recorded, broad-field constant directivity is a bad deal. But, before deciding to convert your L200B's to even more focused three-ways, give constant directivity a try. It can be accomplished for about $225 without doing anything irreversible to your L200B's, and if you decide you like it, an additional $150 will get you quite a decent-sounding system. And if you REALLY like it, we're working on additional upgrades that carry it further.

Here's what you need:

A pair of PTF1010HF Progressive Transition waveguides, the rectangular one, 100° x 100°, JBL Part# 338786-001, $83 each.
A pair of JBL thread-on 1" to 1.5" throat adapters Part# 339308-001, $19 each.
A pair of P-Audio Part# PC-35 or equivalent 1" bolt-on to 1.375"-18 thread-on adapters, $10. http://www.loudspeakersplus.com/html/paudioadapters.html
And here's what you do:

Lay the cabinets on their backs and remove your woofers to gain access to your LE85's and horns. Write down the color codes of the wire connections so you get them correct when mounting them back in.
Remove your LE85's and horns. If L200B is like L200, they're held in by the four screws on the front of the baffle and a steel bracket attached at the LE 85/horn connection wood-screwed to a brace across the rear of the cabinet. Look in there to write down the wire color codes, and disconnect them before detaching and wrestling the horn/driver assembly out through the woofer opening.
Extend the leads for the LE85 (red and white/black on mine) with about 3 Ft. of additional wire. Use small wire nuts from the hardware store to make the connection. Run the leads out through the port.
Block the horn opening with a piece of plywood on the inside (about 6" square will do it) secured with wood screws from the front. Mark and drill pilot holes in the plywood first to make the screwing easier.
Reconnect and reinstall the woofers. Stand the cabinets back up in their listening position.
Assemble the waveguides to the LE85's using the adapters. The P-Audio adapter mounts to the LE85's first using 1/4"-20 flat-head screws, 3/4" long (I used hex socket screws). Then, the waveguide, bolted to the JBL adapter with 1/4"-20 hex bolts, spins easily on.
Set the LE-85/waveguide assemblies on top of the cabinets on something to protect the finish, and reconnect using the wires you've run out through the ports.
Set your crossover level control to the 9:00 position (20% on) and play. The adjstment is very sensitive; move anywhere outside the 8:00 to 12:00 range, and the requisite CD compensation is essentially lost.
Exponential horns such as are standard in L200B's automatically compensate for the inherent falling power response characteristic of compression drivers like the LE85 by progressively concentrating the beam width with increasing frequency. Constant directivity horns and waveguides don't do that, rather, they spread all frequencies evenly throughout the defined sound field, and thus, the crossover output must compensate for the progressively falling response by providing increased power at higher frequencies. The L200B crossover was not designed to do that, BUT, as documented earlier in this thread here (http://audioheritage.org/vbulletin/showthread.php?t=3838&page=7&p=43157), at these lower settings of the level control, it produces an approximation of the desired compensation curve, good enough for assessing the decidedly different character of constant directivity listening.

Surprisingly, you'll find that, even at such low settings, the mid/high vs. bass response is easily established; the LE85's are being driven with about 4 - 6 dB less power in the midrange than originally (though, at the highest frequencies, it is the same). The lens formerly consumed that much acoustic output doing its dispersion thing. Net result, there's lowered distortion in the midrange with constant directivity.

Alas, the "approximation" provided by the L200B crossover is not ideal, but it'll give you a different perspective on what is possible with constant directivity on this two-way system. It has a smooth and mellow vintage character, much easier listening, at least for me, than the standard L200 configuration. If you find that you like constant directivity better than what you're used to L200B's sounding like, there's more you can do to "sweeten" the system coming. See pics and RTA curve, below. On the other hand, if you really hate it, another forum member may want the "gear" you bought to try for themselves.

Recommended test disc: "Red Hot & Blue," Chrysalis #F2 21799, a vintage 1990 compilation recording of 22 Cole Porter songs by 20 different artists and styles from Tom Waits to U2, including the Neville Brothers, Sinead O'connor, David Byrne, KD Lange, others. Get it if you don't have it already. There's enough unmitigated sizzle here to singe your eyebrows. :D

[Zilch]

You'll spend another $150 to acquire a couple of vintage JBL crossovers which WERE designed to provide compression driver compensation, either 3110A (800 Hz) or 3120A (1250 Hz) shown connected in the photo above, and a pair of Parts Express 16-Ohm L-Pads and knobs/faceplates, Part#'s 260-254 and 260-270, respectively, also shown above, front.

Either crossover will work, but they're both compromises. At 800 Hz, the lower limit of the waveguide is pushed. At 1250 Hz, the upper limit of 136A/2231/2235 woofer is pushed (I'm using Giskard's 2235's). Alas, there's no 1 kHz version, though from the sim curves (see link below), 3110A actually operates in that region.

Both of these have a "HF Boost" switch (the "A" designates that,) to adjust the amount of compensation provided to one of three levels, and, similarly, three levels of separate midrange adjustment. Additionally, though, you'll need the L-Pads as a final adjustment of the balance between the mid/high and woofer to compensate for the LE85's having about 4 -6 dB excess sensitivity.

The RTA curve below shows the 3120A with HF boost on max, and the mid level at min, the scenario illustrated earlier in this thread here (http://audioheritage.org/vbulletin/showthread.php?t=3838&page=5&p=42419) for 3110A. The L-Pads are at "+2 dB," a 4 dB absolute attenuation (the center "Normal" position being -6 dB). Result: +/- 2.5 dB to beyond 20 kHz.

These settings are too "hot" for my preference. I set the HF boost back to "mid," and the L-Pads at -6 dB "Normal." There's plenty of adjustment in either direction for most tastes and spaces, probably. I pushed this combination to 95 dB SPL, the limit of my tolerance in this listening space, with no apparent deterioration in sound quality.

Frankly, I'm about to cut wood here. I can cut again if I decide to use the larger square PT waveguide later, and the additional upgrades (drivers and crossovers) we're working on all use these waveguides. My L200's already have the cutout on the rear panel for the 31X0 crossovers (to which I'll add bypass caps, and concurrently separate the LF and HF sections for biamping), and the L-pads will go into the front baffle location of the original level switch. For now, I'm gonna play these sweet old LE85's while we continue working with the B380's and 2431's. :D

[Guido]

Good news Zilch! Thanks for the work.

When do we proceed with the 2431? :bouncy:

[Zilch]

Hi, Guido!

We're waiting for your horns and my additional drivers. I'm actually listening for the UPS truck. :p

I get NO communication from JBL regarding shipments. Stuff shows when it shows, is all, as other forum members have experienced.

Do you have your AM crossovers together yet and your drivers? I'm anxious to know what you think upon listening, i.e., whether you find this to be as significant an improvement as it appears to me here. You'll have to file the mounting holes on your P-Audio horns just a bit to mount the drivers.

[Guido]

I still wait for the drivers. I have an agreement with JBL here THAT they will be delivered but not WHEN!

Nope, the xovers are not finished. I'm still waiting for some parts for the biasing.

How is Widget going with the driver measurements?

[Zilch]

How is Widget going with the driver measurements?We also await the additional new 2431H drivers for measuring.

Seems Mr. Widget is doin' more good stuff with Project May right now. Maybe I get a little listen to that at the same time! :D

[majick47]

I'v been following all the quick & dirty 4430 posts and saw mention of lowering the bass from 30hz to 26hz closely matching the B380. I read that one of the two ports in the L200 could be blocked to get the results. The L200b has only one port and if I read correcly the port tube could be extended to get the same results useing plumbing pvc. Didn't see anything more on the length of the port extension for the L200b. The L300 might also be up for the port extension for 26hz since it shares the same woofer/136a and almost identical cabinet volume. Figure the ports should be the same size in the L200b and L300.

[Zilch]

I'v been following all the quick & dirty 4430 posts and saw mention of lowering the bass from 30hz to 26hz closely matching the B380.I'm refreshing my recollection as to how we got where we are with respect to bass tuning from early on in this project. It derives from Giskard's post on the subject:

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=4&p=40770

I enhanced the low end by applying the BX63's 6 dB, 26 Hz "bump" filter assist to B380 using the 5235 crossover's built-in HPF boost provisions. Giskard suggests there (I think ;) ) that the same approach could be applied to actual 4430's after tuning them lower by blocking one of their ports.

L200 volume and tuning are similar to 4430. The volume I calculated for each is 5.25 cu.ft. (gonna have to recheck that, tho). Both use 4" dia. ports, L200 being 7.25" long, 4430 being 8.25". (4.5 cu.ft. B380's 4" dia. ports are 9" long.) So, I figured that blocking one of the L200's ports would get me into the same 25 - 26 Hz ballpark.

I've not applied the bump filter to the L200's, but, even unassisted, this may be an appropriate extended-bass tuning for the 2235H woofers installed there. I can always remove the plugs and see how they play. In my view, it's kinda like tuning a passive radiator. You can either have deeper bass or tighter, less extended bass, depending upon the tuning you choose. We're making both options available for application as desired.

Regarding the B380's, I'm not using the 5235 crossover right now, so I programmed what I assume to be a 6 dB Q=2 bump into the UltraCurve at 25 Hz. Looking at the 5235 specifications, Q=2 means it slopes to 0 boost two octaves higher, i.e., at 100 Hz. I may have my head in a dark place on that part, though.

If it's desired to similarly adjust the tuning downward on L200B, since it only has one port, the port must be extended, either by adding on to it with a sleeve on the rear inside the box, or by inserting a smaller diameter tight-fitting tube of the appropriate length in from the front (less desireable, since the possibility of port noise from higher velocity air movement is increased). So, we need to find something in the plumbing department that will fit conveniently over the outside diameter of the port tube at the rear, or something the same size and a coupling device to mate on an extension. You'll need to provide that measurement so we can come up with a plan.

You've already told me that the L200B port is 4.25" diameter (inside diameter, I presume,) and that it is also 4.25" deep from the face of the front baffle. I didn't know JBL used 4.25" diameter ports; I thought 4" and 4.125" were their standards in that range, actually.

WinISD says that's a 30 - 31 Hz tuning, near optimally flat according to the program. To move it down to 26 Hz, it says we need about 7.5" total length. I'm guessing that's a better extended-bass tuning, even without adding boost, but I hope Giskard and others with more experience than me tuning bass boxes (a favorite subject here) will weigh in on this, now that we have more of the specifics for them to work with. I have absolutely NO clue what a B6 alignment is, either, so a tutorial might also be in order for the benefit of all us pilgrims.... :p

[4313B]

Here's what got me started -

Back then all we had were Public/University Libraries to go and read this stuff. Now you can just download it for $5. :rotfl:

*****

Probably better off just ordering the Anthologies though.
The Journals should be at a library too.

Google for more information too.

[Zilch]

http://audioheritage.org/vbulletin/showthread.php?t=5209

[Zilch]

Tested L200's w/2235H, one port blocked, using 25 Hz, 6 dB, Q=2 (presumed) "bump" filter assist. Works fine, though maybe not quite so fine as using the same on smaller-volume B380. Reopen the port, and the bump filter doesn't do much of anything, as the box is no longer playing down there.

Recap:

1) Closing one port on 4430 lowers box tuning from 34 to 24 Hz (approx.)
2) Closing one port on L200 lowers box tuning from 35 to 25 Hz (approx.)
3) L200B is tuned to approx. 30 Hz, optimal, but the bass can also be extended lower by lengthening the port and applying the bump filter.

Pic shows the filter and how to implement it using UltraCurve GEQ

[AES Loudspeaker Anthologies ordered....]

[Don Mascali]

Zilch:

I use an Ultra Curve too and the PEQ seems to do a better job. Centered at 25hz with a Q of 2.0 and a boost of 6 db seems to match what they use in the bx63. When the GEQ is used there is some filter interaction when drawing a curve. There is also a way to shelve the GEQ that would probably work too.

Of course this is all theoritical on my part since I can only use the RTA function. I don't have any other testing software or instrumentation.

[Zilch]

Thanks, Don. I let U/C draw the curve itself using BW/OCT = 13/3 there, i.e., expanded to include 100 Hz (which I don't claim to understand).

Haven't used the PEQ yet (U/C is new here), but I'll try that now. :D

Q as used here seems to be a figure of merit relating to crossover performance, not the fc/delta f3 filter parameter that I can discern. BW/OCT behaves reciprocally.

Yup, PEQ works, and sounds better, too. The BW/OCT parameter is unfathomable, though. There's nothing in the manual detailing it to explain why it's different, or what it means, even.

I'm just trying to replicate the Q=2 curve shown for the bump filter in the 5235 manual with it. PEQ looks closer, for sure, if not spot on. BW/OCT=1. Good call:

[Don Mascali]

The BW/OCT is equivilent to Q, or the width of the filter. When you use a 20hz subsonic filter it cuts the low side of the slope and the resulting curve looks very close to the BX63 shape that way.

Thats what I use with my B380 clones and the 4645Cs. Allthough as you have pointed out, room gain does re-enforce it most places that are as small as the typical home listening room.

[Zilch]

When you use a 20hz subsonic filter it cuts the low side of the slope and the resulting curve looks very close to the BX63 shape that way.
That'd be external, right? There's no subsonic filter on UltraCurve, is there?

[Don Mascali]

Yes, I use the low cut on my Yamaha amp. On the 4645Cs I have two mono Behringer PEQ-220s that have adjustabe low cuts that go down to 10hz. I run those a little deeper (15hz) than the B-380 clones for HT grunt.

[Robh3606]

Hey Zilch

Did they take out the Feedback Destroyer in the new model?? You should have 4 parametrics that can be configured for damn near anything in the Feed Back Destroyer. Just set one up as a high Q high pass down in the mud. You should be able to get one to work well as an infrasonic filter.

Rob:)

[Zilch]

Yup, Rob, feedback destroyer is there. "FBD" seems to share the seme 10 available memory locations as PEQ, and can still be set manually.

Y'all're makin' me RTFM here.... :p

[Don Mascali]

Yep, when all else fails, "RTFM":D

[Zilch]

While waiting for JBL! to come through with more waveguides and drivers, we haven't been idle. ;)

We're working on cloning a pair of N3134 (4430) crossovers:

http://audioheritage.org/vbulletin/showthread.php?t=5209

So, the question arises as to how the various drivers and horns play on the HF section of the factory 4430 crossovers (LF disconnected), some with impedance mismatches.

For more discussion, see:

http://audioheritage.org/vbulletin/showthread.php?t=5213

[Zilch]

And on the square PTH waveguide:

[Zilch]

Preliminary conclusions:

1) N3134 is optimized for 2344(A) horn. Can't just swap in the new PT waveguides without adjusting the crossovers.

2) PT waveguides are more efficient in the region of 10 kHz than 2344(A), enough so that it needs to be EQ'd down there unless you want more sizzle, or, like me, are getting older and need the boost. PTF (rectangular) waveguides are slightly "hotter" there.

3) PTH (square) waveguide plays stronger down at 1 kHz.

4) 40-year-old LE85 is a surprise performer in HF extension. Sounds better, too. Not surprising that JBL has gone back to aluminum on some drivers. :p

[I'm playing vintage LE85's on PTH with UltraCurve flattening the 10 kHz bump, and thinkin' seriously 'bout ordering up some D8R2421 diaphragms for them....]

[4313B]

Just for kicks, if you have time would you please run some curves of this network:


Not surprising that JBL is going back to aluminum. :pNew surround technology makes it possible.

[Zilch]

Hi, Giskard!

New surrounds to overcome the aluminum fatigue problems, sounds like.

I'd hafta order parts to build that network unless it's something I can order complete. Pro or consumer?

What are your thoughts for that one? Gonna work with what driver(s)? On PT waveguides?

I'll do it if you say to. Maybe you have some spares to send? Spec the coils, please, and what does "w/7.5 Ohms" mean on the one?

[4313B]

Ok, I'll see if I can dig up a 2.2 uF cap. I can send you a 1.0 mH (7.5 ohm).
I don't really have any thoughts for it. I was just curious how your various horns/CD's would behave with it.

[Zilch]

PE #255-436 @ 0.64 Ohms for the 3 mH coil and 027-436 MPP for the 20 uF?

I have some 2418H-1's here I could try with it as well. JBL's cheapest driver, they have NO HF extension whatsoever that I've been able to discover. Do you know anything about them?

[Robh3606]

"I have some 2418H-1's here I could try with it as well. JBL's cheapest driver, they have NO HF extension whatesoever that I've been able to discover. Do you know anything about them?"

They use them in the new Eon Speakers and the ones I have heard sounded very good. What have you tried them in?? I have a pair on 2342's looking for a home/cabinet was looking into the same crossover Giskard posted to try with them and 128H-1 if I get the cabinets anytime soon.

Rob:)

[Zilch]

What have you tried them in?? Hi, Rob!

They're used in one of the AE series systems on PTF waveguides. I tried them with 4425 crossovers, and there was nothing above 16 kHz, if I recall. Odd, since 2416H plays up there fine.

What's that crossover for? Not a product I'm familiar with, L200t3 apparently....

[johnaec]

I'm curious - 'anyone know the difference between the 2418H and 2418H-1? They definitely have their own specific diaphragms. I'm wondering if the -1 series is the ruggedized version, (like the 2404H-1), resulting in slightly less HF extension, (like the 2404H-1). I've got the plain 2418H series in my little MR922's, but haven't done any objective testing, and 'nothing comparable here to compare them with...

John

[Zilch]

John, we're in "undocumented" territory here, apparently. All's I know is that 2418H is more expensive than H-1. :p

2404H-1 merely used the 2402 diaphragm. I have some 2404H-2, also undocumented.

When Mr. Widget and I opened a pair up to make 076's outta them, they also had 2402 diaphragms. STILL don't know what else is different about them....

[Robh3606]

"I'm curious - 'anyone know the difference between the 2418H and 2418H-1?"

Hello John

The -1 uses ferrofluid in the gap I think the 2418 didn't

"I tried them with 4425 crossovers, and there was nothing above 16 kHz, if I recall. Odd, since 2416H plays up there fine."

Hello Zilch

Well that sucks!!! I was considering swapping the 2214's for 128h-1's to try an L200t3 type speaker or a "super" 4412 in a bigger cabinet to put upstairs in my den in a second HT set-up. As usual I don't know what the hell I am doing until I actually start building them:banghead: . Anything in the post from downunder??

Rob:)

[Zilch]

Rob: No package here yet, alas....

Test out the 2418H-1 and let us know what you find.

I'll run one on N3134 here, set "0."

O.K., on PTH waveguide, not so bad, actually. 4430 curve is obviously wrong for it; too much boost too early. I'm glad you made me check again. It opens some more options.

Read somewhere that ferrofluid squelched VHF response. Not here, apparently:

[Zilch]

Somewhat better on AM crossover we're using with 2431's. "Too much boost too early" was my cue to try it.

Curves are identical below 4 kHz. Use original AM schematic R1 and L4 to punch 9 kHz notch back up, probably:

[Edit: Second unit virtually the same. Kinda exciting, actually. Inexpensive 2418H-1 can substitute for 2431H in "budget" system, maybe. Lessee, is there some L56's in the dungeon? :D ]

[Guido]

I tried them (2418) with 4425 crossovers, and there was nothing above 16 kHz, if I recall. Odd, since 2416H plays up there fine.

Interesting...

Here are my results. Compared a 2418H-1 with a 2416H-1 in a 4425.

[Guido]

What's that crossover for? Not a product I'm familiar with, L200t3 apparently....

Pic courtesy of Rob

L200t3
General Section•Recommended Power Amplifier Range: 200 watts, per speaker•Nominal Impedance: 8 ohms•Woofer: 12" paper cone•Tweeter: 1" pure titanium compression driver•Frequency Response: 42Hz - 20kHz•Crossover Frequency(ies): 1.2kHz•Sensitivity: 93dB (1 watt/1 meter)•MSRP U.S.: $999.00 each

[Zilch]

Thanks, Guido and Rob. How a lovely two-way like that, particularly a Biradial one, slipped under the Zilchster's radar, I don't know. :p

I'll definitely try those crossovers now, as Giskard suggested.

I was WAY wrong on my initial evaluation of 2418H-1. Thankfully, y'all inspired a second look.... :D

[Guido]

How a lovely two-way like that, particularly a Biradial one, slipped under the Zilchster's radar, I don't know. :D

Take the eyes from that avatar :p




I'll definitely try those crossovers now, as Giskard suggested.

I ran it in my spice program. It produces a similar curve than the N3124 while being much simpler.

[Zilch]

Parts for NL200t3 crossover ordered, then.

Here's the parts list for the combined AM/N3134 crossover Guido and I propose to use with 2431H on PT waveguides and 2235H. Seems with adjustment of the notch filter, it could also work with 2418H-1 as "budget" mid/high driver (see above). Right click the spreadsheet and "Print Picture" for a hard copy.

[I'm listening to that combination on factory crossovers now.... :) ]

Edit: In comparison to the LE85's I'm used to of late, 2418H-1's are "crispy."

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

[Chas]

Hey Zilchy, this thread has been a blast, but that avatar is really something else!

[Zilch]

:D

They're the Biradial horns poster girls.

[Giskard made me do it....]

[Zilch]

Any advice how far forward I should move the waveguide? Allegedly, the voice coils should be in alignment. There's some leeway in this, I'd think, as the woofer voice coil is at least 4X the depth of that of the compression driver. I've aligned the mounting surfaces of 2431H on PTF waveguide and 2235H here:

[Zilch]

1) PTF gasket indicates there's not gonna be much baffle left here, so I lay out the smallest practical hole that will accommodate the waveguide. If I moved it forward, it could be smaller.

2) 1" hole saw gives a generous radius on the corners, preserving baffle for support.

3) Four corners complete.

4) The dirty deed itself. MDF is old, dry, and hard. Go slowly, Zilchster....

5) But, will it FIT?

[Zilch]

6) Of COURSE! :bouncy:

[10 mounting screw holes and T-nuts per waveguide. :banghead: ]

7) Play ON, lovely cabs, you have new life....

[Earl K]

- Great Work ! :)

- It's a thing of beauty ! :p

- And you've even left enough room above for a tweeter / should you decide to go that route ;)

- Zilch, what's the internal cu volume of that L200 ?

:cheers:

[4313B]

Tweeters are what you shoot with shotguns.

Then you send your woofers out to retrieve them.

Hope this helps! :D

[Earl K]

Hope this helps! :D

Well, I don't know how long Zilch will be able to resist the Widgets' influence / but mocking tweeters is a good start . ;)

( Hell, even I'm experimenting with tweeters )

:cheers:

[johnaec]

...but mocking tweeters is a good start . ;)Out here they call them mocking birds. :uhmmmm:

John

[Alex Lancaster]

;) And squakers are also called in-laws.

[Zilch]

Zilch, what's the internal cu volume of that L200 ?
I earlier estimated the volume at 5.25 cu.ft., essentially the same as 4430. Gonna have to drop a plumb line to get the sloped front panel measured correctly. I'll do that today, 'cause I need to know the angle for other puposes, too (see below). It's a good design approach; despite low profile, they don't play to the knees.

Gettin' the waveguides with mid/high drivers into the cabinets made a big difference, too. Them sittin' on top of L200's for experimentation was a long way center-to-center-wise from the woofers. They now sound "integrated."

No tweeters, nope, nope. [045Be birdie would JUST fit, though.... ;) ] It's a matter of pride. We're committed to making two-ways work here, and this new technology certainly helps. We also discovered that some of the really OLD technology can be made to play a hella lot better than anticipated, as well.

Tried some 2404's a couple of pages back, and they didn't give me any more measurable extension than we already have with 2431's, just the ability to drive the VHF way out of proportion. I DO have a pair of 2435's I can put in there, tho, once JBL makes them "right." :p

Nobody's gonna bite on the time alignment thing, huh? I was surprised to see how shallow 2235H is once set up for side-by-side comparison. Just can't figure out where the "centers" are that are supposed to be aligned. If Mr. Widget measures them, we can get the answer, but I have to build up the final crossovers first.

One other thought: I may have been overly concerned about compromising the rigidity of the front baffle. The waveguide is itself quite thick and stiff, and easily supports the light-weight Neodymium driver as a cantilevered load. By the time I put 10 screws in each of them, and mounted the woofers, some of the lost baffle stiffness is restored. Gonna think again 'bout whether I HAVE to put bracing inside, but I'll likely do it anyway.

'Course, what with the sloped panel there, I'll have to buy a compound mitre saw and some nice kiln-dried lumber to do that correctly.... :D

[Earl K]

Nobody's gonna bite on the time alignment thing, huh? I was surprised to see how shallow 2235H is once set up for comparison.

I'd suggest putting some of the known dimensions into a drawing .
- You do need to know the slope of that baffle .
- Relative locations of the component on the baffle
- Relative locations of each components' voice-coil ( approximate the mid point inside the gap )
- Need to know approx . convergence point of woofer & horn ( ie ; where you are likely to be sitting ,,,, sitting height and distance from boxes )


Just can't figure out where the "centers" are that are supposed to be aligned. If Mr. Widget measures them, we can get the answer, but I have to build up the final crossover first.

Yes :
- find the acoustic centers for a few commonly used crossover frequencies on a few of the available, "obtainable" components / such as / the 2235, the 2431 on xxxx horn-wavequide / 2426,2418 on xxxx horn waveguide . You get the idea .


:cheers:

[johnaec]

- Relative locations of each components' voice-coil ( approximate the mid point inside the gap )Wouldn't you want the *radiators* lined up, not the voice-coils? Think of it hypothetically - what if the diaphragm dome was something like 2" behind the voice coil? That's where the sound waves actually eminate from, not the center of the voice coils. I admit - the sloped/curved format of the LF speaker cone make for a somewhat confusing situation...

John

[Zilch]

It's deceiving, because the sloped front baffle is recessed 4-5/8" behind the also sloping front edges.

Slope is -6.8817°

Internal volume is 4.9755 cu.ft.

Port is 4" dia. X 7.25" deep.

WinISD says I'm tuned to 25.7 Hz.

I must tell y'all, it was a pleasure taking the measurements with them playin' Shirley Horn so sweetly here.... :)

[Earl K]

Hi John


Wouldn't you want the *radiators* lined up, not the voice-coils?

- Voice-coil alignments are a simplistic approach to the problem / I'll grant that .

- I believe it's quite a bit more complicated than just aligning all the sound producing membranes. The physical location that a person "assumes" should be point zero for the generation of a sound wave and where test equipment actually places that same "apparent" acoustic center / will just about always be two different locations in space .

- Only through the use of test equipment can a person expect to achieve reasonable alignment .


Think of it hypothetically - what if the diaphragm dome was something like 2" behind the voice coil?

Once in a while I do think about these electromechanical paradoxes / but then my head begins to hurt . :p

:cheers:

[spkrman57]

I usually refer to the voice coils as the "acoustic center". Not sure how accurate a statement that is but just my 2 cents worth!
Ron

[Zilch]

I can see now how the time alignment defines a horizontal plane in space where the distance from the "centers" (wherever they are) is the same, according also to the electrical phase relationship between the drivers.

Depending upon where I read, for 4430, that plane is tilted either 10 or 15 degrees upward from some point between the drivers.

If the drivers are aligned vertically, and perfectly in phase, that plane is perpendicular to the face of the baffle, i.e., on L200, it would be tilted 6.88° upward.

The closer the drivers are to each other, the less phase change occurs with vertical displacement from the plane of time alignment. If the "centers" are coincident, as in a perfect coaxial alignment, there is no change.

The absolute phase shift varies with wavelength, and is of most interest in the crossover region, where both drivers are playing the same frequencies. Outside of that region, it translates to group delay.

Well, that's my impression of it so far from reading here in the forum. The AES anthologies are on the way, and I'll hopefully be able to refine my own understanding.

Seems the answer is, "You gotta measure it."

Looking at the physical alignment of 2426H and 2235H in 4430's, there's a substantial element of BS involved in this, as well.... :D

[Ian Mackenzie]

The drivers have a phase shift in the pass band generally so this will also vary with frequency.

I prefer the square wave test.

Ian

[johnaec]

I can see now how the time alignment defines a horizontal plane ... a substantial element of BS involved in this, as well.... :DNow MY head hurts! :o:

John

[Zilch]

Now MY head hurts! http://audioheritage.org/vbulletin/images/smilies/redface.gif Come down here and listen to these puppies.


All will be well.... :)

[Zilch]

Constructed at Giskard's suggestion with these parts:

http://home.att.net/~i_am_zilch/N200Ti_Parts_List.jpg

Using breadboarding methodology dormant with the Zilchster for 35 years, simple crossovers yield surprising results with 2427H's on 2344A Biradial horns. 7-Ohm resistors are in series with L2 to comprise the requisite 7.5 Ohms. Boards are 5" X 6".

The sound? Clean, balanced, "sibilent." These are keepers :D:

[Zilch]

2.2 uF caps were out of stock; results above substituting 2.0 uF, which may account for valley at 1.6 kHz.

Performance of HF section:

1) 2427H on 2344A Biradial.
2) 2418H-1 on PTH Waveguide (alas, no 2342 here....)
3) LE85 on PTH Waveguide, wrong impedance.

[Again wishin' I had 8-Ohm aluminum diaphragms for LE85's....]

[Zilch]

Where's the CD compensation and HF boost comin' from?

These are simple 2-Pole, 12 dB topology, no?

What woof came with these? (B380's playin' above.)

Interestingly, RTA said invert the HF phase....

[4313B]

"Where's the CD compensation and HF boost comin' from?"

The 2.2 uF high pass is a simple single pole filter with the opposite roll-off of the Horn/CD. Think about that for a moment.

"These are simple 2-Pole, 12 dB topology, no?"

2-pole LP and 1-pole HP

Pull the 1.0 mH 7.5 ohm conjugate and run your plot again. See what frequency range that conjugate is affecting.

"What woof came with these?"

120T3

"which may account for valley at 1.6 kHz"

Probably a different resonance peak. You will need to run an impedance curve of your current horn/cd and then run an impedance curve of the stock 2416H/2342H combination for comparison. Adjust the 1.0 mH 7.5 ohm conjugate accordingly.

Added L200T3 voltage drive with 8 ohm loads (04-10-2005, 12:40 AM):

[Zilch]

CAUTION: schematic erroneously has 2 L1's. I renumbered the one in HP (1.0 mH) to L2 for clarity.

Gonna have to think about Giskard's response here. Itza conjugate. :hmm:

Ah-HA! 2.2 uF with 8 Ohms is 9 kHz, about. With 20 Ohms in parallel with the HF driver, it's more like 5.7 Ohms impedance, so the rolloff frequency is even higher. 7.5 Ohms in series with L2 makes it a conjugate, not a pole. I'm startin' to get it.... :D

[4313B]

"20 Ohms makes it more like 5.7 Ohms impedance"

Yeah, impedance curves are your friend. It'd be nice to see some for all of these horn/CD combos you are doing.

I'm also looking forward to impedance curves of all those ring radiators you guys are going to run plots of...

Post all the data files if you wouldn't mind. They should be simple comma or tab separated values text files that other forum members can pull into the software of their choice.

In any case - Thanks for this R&D thread! :)
I hope other forum members see the value because there is quite a bit here.

[Zilch]

In any case - Thanks for this R&D thread! :)

I hope other forum members see the value because there is quite a bit here.It's mostly good fun, actually!

[Never thought I'd be itching from drillin' fiberglass breadboards again, tho.... :p]

Thank you for your informative contributions and guidance here!

[Guido]

Probably a different resonance peak. You will need to run an impedance curve of your current horn/cd and then run an impedance curve of the stock 2416H/2342H combination for comparison. Adjust the 1.0 mH 7.5 ohm conjugate accordingly.

Yep, 2416 has resonance peak at 1,4 kHz, 2426 at 1,1 kHz. I'll dig my impedance curves out.

[Guido]

[Again wishin' I had 8-Ohm aluminum diaphragms for LE85's....]
Adjust the parallel resistance accordingly

[Earl K]

Hi

- Question has been moved here. (http://audioheritage.csdco.com/vbulletin/showthread.php?p=49898)

:cheers:

[4313B]

It's mostly good fun, actually!Ok, whatever.

Adjust the parallel resistance accordinglyThat's possible to a degree. One would have to run impedance curves of the 8 ohm and 16 ohm versions and then run an impedance curve of the 16 ohm version with the parallel resistance. Compare the results.

[Zilch]

1) With HF conjugate
2) Conjugate disabled

It's working at 15 - 20 kHz looks like, doin' the HF boost?

Maybe some action down at 1 KHz, as well.

[Very clevah.... :) ]

The relevance is that for $72.76 a pair and a couple of hours breadboarding time, these little crossovers are credible performers with the "Quick & Dirty" combo using 2344A horns on 2426H. They'll likely work even better than I have demonstrated with the proper 2.2 uF caps in there, and with Guido's impedance curves, we may be able to "tweak" them a little more.

Apparently, they'll work for 4425 clones as well, using 2342 horns and the smaller 241XH drivers. Sounds like RobH's maybe gonna try that....

[Zilch]

Adjust the parallel resistance accordinglyThat'd knock the HF output down 3 dB, no?

Then I'd have to biamp them to get it back. :D

[Separate LF & HF inputs shown in pic above (bottom, outputs top) allow for that, tho....]

Doubling C3 and maybe adjusting the conjugate would be a better answer to using a 16 Ohm HF driver with them?

[4313B]

It's working at 15 - 20 kHz looks like, doin' the HF boost?

Maybe some action down at 1 KHz, as well.It would be nice to measure the stock L200T horn/CD.
Here's what the conjugate is doing with a 2425H/2344A:

[Zilch]

It would be nice to measure the stock L200T horn/CD. Rob gonna do that, I betcha.... ;)

Hmmmm. No action above 10 kHz?

[4313B]

No, it's a conjugate targeted to a specific range. It's designed to reduce the impedance of the resonant frequency of the load. You can see in the graph where is ceases to have an effect.

[Zilch]

Real impedance above 10 kHz is about 3.5 Ohms, so 2.2 uF HP is rolling down from above 20 kHz, as you showed last night.

My 2.0 uF is starting even higher, so me getting the right value in there may lift the dip at 1 kHz a bit. :)

I'd imagine being off by 10% in this matters, if not considerably. We'll see when the right parts get here....

[4313B]

Ok. You can see from my graph that both runs are at ~ 3.5 ohms at 10 kHz so we seems to be in agreement there.

Yes, the 2.2 uF should increase the output a bit.

How does it actually sound right now though?

Cyan shows the voltage drive with a 3.5 ohm load rather than 8 ohm load.

Magenta shows the 2.0 uF with a 3.5 ohm load. It looks like the 2.2 uF is worth roughly 0.84 dB across the bandwidth.

[Zilch]

How does it actually sound right now though?

They are balanced, clear, with crisp (even sibilent) highs. They're on a platform truck about 4 feet out from the wall with "stuff" behind them, so boundary effect and room response would enhance the bass in a normal listening environment. I can hear it's there aplenty.

Not as transparent as true 4430's, they're more like big 4425's. :p

I've come to rely substantially on RTA for setup and performance evaluation; if it says they're within +/- 2.5 dB, I'm done. Attempting to tune better than that in this room (garage) is fuitless.

I have an L-Pad on the HF, but it's been at full on ever since I hooked them up. They're set up for biamping, too, and if I REALLY want to dial them in, I could use the UltraCurve....

[4313B]

So then, not bad for a minimal network eh?

[Zilch]

If it can be said that I have an angle, it's "simple." :D

Most folks don't have an LCR meter to tune custom inductors, or an RTA to test the results. Virtually anyone can make a set of these and enjoy the outcome.

Something this cheap and easy to build from stock components that plays this well definitely gets the Zilchster DIY Seal of Approval. :thmbsup:

B380 - BYO
2235H - $300
2426H - $200
2344A - $220
N200T3-$80

TOTAL - $800/pair

Satisfaction from having built 'em yerself - "Priceless." :cheers:

[Guido]

Yep, 2416 has resonance peak at 1,4 kHz, 2426 at 1,1 kHz. I'll dig my impedance curves out.

Here are some impedance plots.

First pic
2426 on 2344 with D16R2421 (red), D8R242h (blue) and 2420 on 2344 with D162421 (orange).

Second pic
2418H on 2342 (red), 2416H on 2342 (blue)

[Mr. Widget]

1) With HF conjugate
2) Conjugate disabled

It's working at 15 - 20 kHz looks like, doin' the HF boost?

Maybe some action down at 1 KHz, as well.

[Very clevah.... :) ]

The relevance is that for $72.76 a pair and a couple of hours breadboarding time, these little crossovers are credible performers with the "Quick & Dirty" combo using 2344A horns on 2426H. They'll likely work even better than I have demonstrated with the proper 2.2 uF caps in there, and with Guido's impedance curves, we may be able to "tweak" them a little more.

Apparently, they'll work for 4425 clones as well, using 2342 horns and the smaller 241XH drivers. Sounds like RobH's maybe gonna try that....

Am I missing something here? Aren't you concerned about being about 10dB down at 1.25KHz compared to 10KHz or am I reading your plots incorrectly?

Widget

[Zilch]

Naw, 'cause the woofer plays there too. There's a dip a little higher, tho....

http://audioheritage.org/vbulletin/attachment.php?attachmentid=6583&stc=1

[Zilch]

I have an L-Pad on the HF, but it's been at full on ever since I hooked them up.Which raises an issue: Stickin' anything other than maybe a 4-Ohm L-Pad immediately ahead of the driver's gonna shift the rolloff frequency around, since the HF network wants to "look into" 3.5 Ohms. "Nominal" 8-Ohm L-Pad would move it down a full octave, worst case, at max attenuation, no?

Alternatively, you'd have to know and match the network impedance to put one ahead of it, as well? :banghead:

[Maybe I'm over-thinkin' this....]

EDIT: Hooked up a 3.5-Ohm resistor to an 8-Ohm L-Pad. Indeed, it varies essentially linearly from 3.5 Ohms at full on to 8.5 Ohms max at about 80% attenuation. It'd take some fancy writing to make that a "feature." :p

[4313B]

Build something like a 3-position switch with fixed resistors. Something like 0 dB, -1 dB, -2 dB.

You could also get an L-Pad to work between the 2.2 uF capacitor and the 1.0 mH (7.5) inductor and then adjust the value of the 2.2 uF accordingly.

[Zilch]

Along with Guido's PTH waveguides, a new pair of 2431H drivers came in. I mounted them in the modified L200's on PTF waveguides. No EQ, just the AM crossovers we're using, here's the performance, L & R:

Get OUTTA here!!!

[4313B]

:p

[Zilch]

Build yerself a pair of these using LE14H-1 ('cause I've got your 2235H's, now. :p ) They could be KILLER!

[AND, you could help us tweak this combo, first hand. ;) ]

[4313B]

Oh it's tempting!

I've still got my 4430 horn/cd combos and managed to pick up a 3rd NOS horn not long ago for a center channel... still looking for a third perfect 2425H...

[Zilch]

Build them for your rear channels, then.

And spin your chair around when you want to listen to jus' them! :D

[Gotta have more than ONE system to play, anyways....]

[Earl K]

Hi Zilch


Along with Guido's PTH waveguides, a new pair of 2431H drivers came in. I mounted them in the modified L200's on PTF waveguides. No EQ, just the AM crossovers we're using, here's the performance, L & R:

- Nice matched set of drivers .

- I'd like to see what they can do on a 650 hz horn with a low crossover point . Do you have any horns like that ?

- A quick suggestion ; I just spent about 10 minutes using the search engine to try to find ( within this thread ) the technical info that relates to your "AM" crossover reference . Maybe for the rest of us, you could note what post that info is found in so we can follow along . Thanks !


:cheers:

[Zilch]

Hi, Earl.

"AM" crossover refers to HF section of AM6212/00, the JBL product which uses the 2431H on PTH (12" X 12" square) waveguides, but in combination with the LF section of 4430's N3134. Guido's building with 4435's N3135 LF.

I put together a parts list here:

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=21&p=48600

Note that R1 and L4 values are a little different in the HF section; we're using what actually came on the factory crossovers to start, which are not what's on the schematic:

http://www.jblproservice.com/pdf/AE%20Series/AM6212,00-WH.pdf

JBL varies the HF crossover a bit depending upon which version of PT waveguide is used:

http://www.jblproservice.com/pdf/AE%20Series/AM6212,64-WH.pdf

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

The simplest configuration seems to work with the PTF rectangular 100° X 100° waveguide as well, (see most recent RTA plots, above,) though we may be "finessing" them a bit with more experience.

I'm still using factory crossovers for both sections right now, waiting for parts to come in to complete my own DIY versions, in progress.

Ooops, there's the UPS guy right now..... :D

[Zilch]

I'd like to see what they can do on a 650 hz horn with a low crossover point. Like 2435H, I suspect they'd require the larger back cap to play worth a whit below 800 Hz.

I could try them on the P-Audio 2344A clones, which are spec'd down to 500 Hz, but I don't have any true MF horns here for a REAL challenge....

[Earl K]

Zilch

- Thanks for the AM update. I'll take a look at all that info this weekend .

- Now that you've established the HF capabilities of the 243x series / I would love to see just what it can do in the lower regions .

- One of the reasons I published those RTA pics of the B&C 900 / RCA horn was to demonstrate just how much lower midrange can be obtained when a large horn is used. By the way ; The cut sheet on that driver actually recommends a 1200 hz point ( at 12 db / octave ).

- Considering the 2431s' top end extension , I'd love to see what those 2431Hs are capable of on the H9800 . That would be a reasonable test / even with the tight back-cap . How about you and the Widget hooking up sometime in the future to suss this out ( or is the H9800 travelling ? ) Anyways

chow <> :cheers:

[Zilch]

1) DIY crossovers, nearly complete, await delivery of a few coils from Parts Express. N3134's (top) incorporate full original switching plus Zilch's new "Biwire" option using available 6th switch pole. AM version (bottom) for upgraded L200's is way simpler.

2) Switches for N3134 are prewired using 18 Ga. (16/30) hookup wire; 12 leads total required. They made construction a decidedly non-trivial endeavor. I had to break out the magnifying visor to build them, and it took over an hour apiece to do it. Wire colors denote six different switch functions, so the Zilchster gets the connections right.

3) Rear of N3134's prior to switch installation (bottom) and after (top). Bifurcated terminal ends (see unwired ones there) permit secure point-to-point wiring. Components are laid out to simplify it and minimize lead crossings, as if it were a printed circuit. 1/8" thick electrical-grade fiberglass substrate will mount on recessed rear panel per JBL convention. Boards are 7" square.

The input terminals used here are REdiculous. They'll accommodate lead wires the diameter of a pencil.

[Ordering up more of them for the AM boards, now.... :D ]

[Guido]

Nice work Zilch!

So you're not gonna bias the AM's?

The biased 4313 sounds so awesome that I gonna bias the 3135 and the AM's for sure.

BTW Horns are locked up in the custom. But no problem I'll get them out soon :D

[Zilch]

So you're not gonna bias the AM's?Next project. :p

Thought we'd better get these "optimized" first.



Horns are locked up in the custom. But no problem I'll get them out soon Guido's gettin' his PT-H1010HF waveguides.

NOW this thread'll see some ACTION!

:rockon1:

[Hopefully, he's got his 2431H drivers to go with 'em, too....]

[Zilch]

Sonofagun's L200 grilles arrived today. Not glued to screens yet, they're just sittin' there lookin' like a million bucks! RTA finds them to be acoustically transparent.

While the texture is different, of course, the color is a close match to JBL Monitor Blue. Look closely at the closeup pic, and you'll see there's a swatch of factory grille cloth stuck on there for comparison.

Do we know the JBL Part# of those little plastic pinback logos? It'd be good to save forum members the embarassment of paying $25+ for them from the Orange County reconer guys.... :biting:

Can ya hear 'em? That's Brian Ferry's "Frantic" they're playin'....

[Mr. Widget]

Do we know the JBL Part# of those little plastic pinback logos? It'd be good to save forum members the embarassment of paying $25+ for them from the Orange County reconer guys.... :biting:

I have a pair of the original metal logos that are appropriate to the L100 and L200 among other JBLs of the era... If there were a number of members interested in them I could do a run of 20+ and they should be about $5 ea. maybe less.

Widget

[Zilch]

See pic in post #366. That's a 50 CFM Comair Rotron "Whisper XL" fan there, $27.40 at Digikey (#CR117-ND), plus $1.79 each for finger guards (2 required, #CR210-ND) and $1.80 for the 3' plug-on cord (#CR371-ND):

http://dkc3.digikey.com/PDF/T051/1372.pdf

Virtually silent in operation, it's just powerful enough to pull the solder fumes away without cooling the work. 70 and 83 CFM versions also listed there, same price, not so quiet, probably.

Ask at the target range if lead fumes are hazardous to your health. There's no sense breathing them directly....

[Guido]

[Hopefully, he's got his 2431H drivers to go with 'em, too....]

I need to fill my wallet first :(

Too many projects at the same time at the moment.

Buying a house (obviously the most cost effective :D )
Biasing 4313 clones
Building 2203 based Subs
Building the 4435 clones

I'll first test the Waveguides on 2426 and 2421 drivers in Ralf's 4430 clones.

[Zilch]

I need to fill my wallet first :(

Too many projects at the same time at the moment.You have NO sense of priority.

NOTHING matters but this.... :p

[Zilch]

I have a pair of the original metal logos that are appropriate to the L100 and L200 among other JBLs of the era....

We'll talk.... ;)

[Zilch]

I've received several inquiries regarding my crossover construction method illustrated above. The push-in terminals I'm using were discontinued and the tooling destroyed 30 years ago. I only have enough stock for my own use presently.

BUT, I'm trying to round up more from surplus and grey-market sources right now. If there's enough interest, I'll consider making new tooling to produce them....

[Zilch]

Quote from another thread:

"Given the room finishes I would steer away from the 4430 bi radial unless you propose to damp the walls.

The wash off these monitors will overpower the direct radiated sound to your ears otherwise."

Certainly early reflections can be a problem with wide-field biradials in a "live" listening environment, though JBL touted this as a desireable feature in monitoring installations. It has not been a problem in my garage, apparently because there's so much other "stuff" in there. Note that the 4430's controlled 100° horizontal field is already somewhat narrower than that provided by the dispersion lenses of earlier monitors. Everything in context.

Edit: On this subject, from the Project Everest White Paper:

"Some loudspeakers which have a wide radiation pattern tend to produce a rather "spacey" sound, inasmuch as they may bring into play considerable local room reflections. Many listeners at non-center positions mistake this for cues in the recording itself, and such loudspeakers give the impression of richness in ambience, but of course without precision of localization."

We earlier discussed the availability of dispersion patterns other than the 4430's 100° X 100° in Progressive Transition waveguides which might serve to satisfy those who prefer a narrower field. They're available in 100° X 100°, 90° X 50°, 70° X 70°, and 60° X 40° versions, in both square and compact rectangular (my preference) format.

Here's the PT-F64HF, the 60° X 40° version, shown also in comparison the PT-F1010HF (right) which I am presently using. It's quite solidly molded, heavy even. Note the difference in depth between the two versions. Time alignment might be more akin to 4430 standard, though that would have to be confirmed with testing.

K2-S9800 and Project May use a 90° X 40° horn (correct me if I'm wrong, please). Apparently JBL has never produced a compact PT-F version other than prototypes in that pattern (no current products use it), but a square PT-H95HF 90° X 50° is available for those who might prefer controlled vertical dispersion and reduced early ceiling/floor reflections. 4430's identical 100° horizontal beamwidth for both LF and HF drivers at crossover seamlessly melds the system into one source, according to JBL design....

[Zilch]

Also available is the 1" thread-on SF horn used in AC2215/95:

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

It's really "plastic" in comparison the PT waveguides, without even a metal threaded insert such as the OASR horn has, but it's also really cheap at $9.90. :p

Worth a shot for those wanting to experiment with the 90° X 50° pattern using smaller drivers like the 2418H-1 shown here. I haven't played them yet, but I'm bettin' they're gonna require a generous slather of damping material on the back:

[Guido]

Today I released my PT Waveguides from the customs. Wasn't really a problem :D

Thank you so much Zilch!

I like these Horns! Ralf and myself will test them soon with 2426's in his 4430 clones.
As written before I have to wait with the 2431 drivers. :(

[Zilch]

Good DEAL, Guido!

They're gonna play too "hot" in the 8 - 10 kHz range, so you'll need some EQ until you get your 2431H's and the AM crossovers running.

We're eager to hear how you like them in action.... :)

[Butt-cheeks suddenly become flat-ass!]

[Ian Mackenzie]

Zilch,

Excellent summary above.:applaud:

I will have to consult your expertise on a new prototype system when I clear my project bench.:help:

Ian

[Zilch]

DIY 4430 (N3134) crossovers complete including "Biwire" option:

http://audioheritage.org/vbulletin/showthread.php?p=52926#post52926

[Zilchster will listen now.... :D ]

[Zilch]

RTA measurements of three crossovers:

1) Factory N3134 (4430, left)

2) DIY N3134 (details in above-linked thread)

3) DIY N200T3 (right, discussed earlier here)



The "Objets d' arse" they're measured on:

1) B380

2) 2344A

3) 2427H with 2426 throat adapter


Each of the three run full range on a single JBL 6260 amp, i.e., not biamped.

[Zilch]

1) N200T3 presented first for proximal comparison to factory crossover results
2) Factory crossover at "0" setting
3) Factory crossover at max flat setting for this room
4) DIY N3134+ before inductor tuning (stock values per parts list)
5) DIY N3134+ after inductor tuning and set max flat also (values per schematic)

[Zilch]

How do the new DIY versions sound?

Cleaner, crisper, brighter, even "sibilent" in comparison to factory stock crossovers.

Same thing I said about N200T3's earlier.

I've built 4 DIY crossovers now, and I'm starting to think this "signature" is characteristic of Dayton metalized polypropylene capacitors bypassed with Theta film-and-foils. They all sound like this.

The response curves are quite good, as may be seen above. They were less bright before retuning the inductors to schematic values....

[Guido]

Respect!

Which inductors did you retune?

[4313B]

"sibilent"Really? :hmm:

adj.
Of, characterized by, or producing a hissing sound like that of (s) or (sh): the sibilant consonants; a sibilant bird call.
n.
A sibilant speech sound, such as English (s), (sh), (z), or (zh).

See if they need to play for a few days...

***

:banghead: Ah! I forgot you aren't running them biased...

[Zilch]

Which inductors did you retune?Hi, Guido!

Nothing special, I just brought all three to N3134 schematic spec. Gonna put that over in the construction thread. :p


Really?I don't know how else to express it. The vocalists' consonants have more sibilence on these, without being "harsh."

Remember also, this is a garage listening room, tho Widget can attest it's not as "live" as might be expected. :D

For the first time ever, I was also shocked to hear the separate notes of mandolin string pairs resolved distinctly.

[Gonna listen to that again today to be sure I wasn't imagining it.... ;) ]

[DMMD]

Interesting observation Zilch...

Like an extra dimension of breath? "Breathiness"

How about: Forced vocalization, as in hearing the process of sibelant sound forming? If you think about it, there are specific air movements that create the ability of one to produce those consonants.

I suppose- extra details if you boil it down to the minimal expression. :blink:

Then again, it could just be a hiss from the snake trapped in your box...

[Zilch]

:banghead: Ah! I forgot you aren't running them biased...Yeah, that's the next crossover project, most likely. I didn't want to take big leaps here.

It may also be that's just how these combos play with titanium diaphragms, tho I'm not gonna assert that on the basis of this limited experience....

[4313B]

It may also be that's just how these combos play with titanium diaphragmsCould be... I've only tried that combo with direct radiators.

[Zilch]

Interesting observation Zilch...

Like an extra dimension of breath? "Breathiness"

Yeah, that too. :p

Mackie would call it "Air," probably....

I've only heard them for a couple of hours, though, and it ain't as if I have no bias here....

[Zilch]

Could be... I've only tried that combo with direct radiators.I'll send ya the N200T3's to play with. :)

[Then RobH wants them to try, probably, for his 4425 project....]

[4313B]

No thanks! :no:
Mike would kill me, and rightfully so, if he knew I was screwing around with my 4430's instead of working on his subs. :p
Send them directly to Rob. :)

[Zilch]

O.K., so what's this tell me about 2431H on PT-F waveguide?

[4313B]

It tells you that you need to get some impedance compensation going on.
That's not too awful though! JBL is getting good with the impedance curves on these transducers!
Post the data file.

Run an impedance curve on just the 2431H so you can see how the waveguide is loading it.

[Zilch]

O.K., new runs, first with waveguide, then just the 2431H driver.

Supposedly, not good to run the driver with no horn loading, but the current is only 3 mA, .054 mW typical, 0.1 mW max, if my math is right. Still loud, tho.... :p

Compression drivers are quite amazing. Seems like a coupla wires stuck in a potato would play 'em....

[4313B]

Supposedly, not good to run the driver with no horn loading, but the current is only 3 mA, .054 mW, if my math is right. Still loud, tho.... :pYou can run any driver with that and not have a problem. Don't forget the C.D. is roughly 118 dB with 1 W without any horn loading. That's why it's so loud with minimal input.

If you could post the output files for BB6P in a zip that would be neato.

The bb6p .log file will include the sweep necessary for the Q and Fs test.

The .woo file should be the same as the exported .txt file.

Here's what I just got running a 2425H/2344A

[Zilch]

It's certainly clear in comparing the curves from the two different driver families that they require different crossovers.

What sweep ratio did you use there? I used 1.0, then switched back to the default 1.3 for the Q test. Run below is at 1.1 for 104 data points.

[4313B]

I can't remember what I put the number of points on, it was high though.

I wanted my graph to look as much like yours as possible for this little exchange so I started at 500 Hz too. Makes sense for these specific combinations.

[Zilch]

Here's the same 2431H driver on square-format PT-H versus rectangular PT-F waveguides. Both are 100° X 100° shown earlier in this thread.

Surprisingly, smaller PT-F waveguide combo has lower Fs. Not shown, Fmin, the equivalent of box tuning on a LF system, is 1288.49 Hz for the PT-H, and 1087.54 Hz for the PT-F. Seems I may have made a good choice between the two for the L200 upgrade described earlier here.

Crossover tuning will be slightly different for them as impedence peaks occur at different frequencies, but above 3 kHz, they appear to be virtually identical.

What's this about? New Dayton Audio "Woofer Tester 2" quickly and easily runs impedance curves on compression driver/horn combinations as well as woofers, providing information for importing into BB6P software for crossover design.

http://audioheritage.org/vbulletin/showthread.php?t=5662

It connects to USB port, which provides the requisite power for these small-signal measurements, and runs even on crappy old machines like this Compaq WIN98 SE system.... :p

[4313B]

2430H

[4313B]

2431H

[4313B]

2435H

[Mr. Widget]

Very interesting... look at those high FS numbers. Also look at that pronounced ~14Khz breakup mode on the 2431H... no wonder it sounds a bit harsh.

The 2435H is definitely the one to get. We should measure the Fs change when adding a larger back cap.

Widget

[Zilch]

WOW, Giskard!

Thanks for getting the scoop on the 243X drivers for us!

Looks like Woofer Tester's doing a resonable job on the measurements of actual units, here.

My 2435's don't seem to have HF extension like the spec shows. Guess I'll be sending them back to JBL for a warranty look-see as anticipated....

[Mr. Widget]

My 2435's don't seem to have HF extension like the spec shows. Guess I'll be sending them back to JBL for a warranty look-see as anticipated....

Let's measure them with Clio first... I hope to have time in about a week. From my reading of the plane wave tube measurements your drivers may be up to spec... let's measure them.

Widget

[Zilch]

Very interesting... look at those high FS numbers.Fs shifts downward substantially (~150 Hz) when mounted on PT waveguides. See WT2 test data above comparing it with raw driver.


The 2435H is definitely the one to get.The problem is the PRICE, of course. At $1000 more per each list, they're a bit "dear." :(


Also look at that pronounced ~14Khz breakup mode on the 2431H.~17 kHz on the 2435H. We'll see what's actually happening on the waveguides when we measure them.


No wonder it sounds a bit harsh.Seems you and me're the only ones what's ever actually HEARD 'em. ;)


We should measure the Fs change when adding a larger back cap.Easily done. Maybe Steve will loan us one of his for testing? I'm not ready to start pokin' holes in mine yet.


Let's measure with Clio first.Next week will be fine. We've got a BUNCH o' stuff to measure here, now.

[I've made a little list.... :p]

[Earl K]

:)

(a) Well, a mighty large Thank-You is in order to Giskard for the recent publishing of this 243x compression driver info .
So ; THANK-YOU !!!

(b) And also, thanks to Zilch, who through his continued investments in & his personal studies of ( JBLs' newer "PRO" offerings' ), has had an incalculable effect towards enlightening the rest of us about these SOTA products .

Thanks All Round to both you Guys <> EarlK :applaud:

[Guido]

Thank Giskard this 243x mystery problem is solved :applaud:

Our friends at JBL had mercy!

I'm looking forwrd to the Clio results. I'll order my 2431 drivers in June. They are on stock :)

[Zilch]

I, me, the Zilchster, being this day sound of mind and substantive in consciousness, do hereby and herewith certify and attest that biased and bypassed HF crossovers do sound better than merely bypassed ones of identical composition.... :p

[Guido]

Yes! Ja! Si! Da! ....................

[4313B]

I, me, the Zilchster, being this day sound of mind and substantive in consciousness, do hereby and herewith certify and attest that biased and bypassed HF crossovers do sound better than merely bypassed ones of identical composition.... :pThat's what I said, but what I say doesn't mean much. I'm glad you and others are trying the technology and posting your results. It's fun.

http://audioheritage.org/vbulletin/showpost.php?p=32732

[Earl K]

I, me, the Zilchster, being this day sound of mind and substantive in consciousness, do hereby and herewith certify and attest that biased and bypassed HF crossovers do sound better than merely bypassed ones of identical composition....

:D ( Okay, one convert at a time is better than none ) :p

- FWIW;when using my surplus Polystyrene caps , a "DC-biased" Line Level HiPass Filter also sounds noticably more in focus/ "or clearer,sharper" than the non-biased variety .

- I've never tried a "bypassed" LLHPF and have yet to build a LLHPF using the approach of paralleled caps with flipped/mated electrodes ( for some ad hoc signature resonance-cancellation ) .


:cheers:

[4313B]

- FWIW;when using my surplus Polystyrene caps , a "DC-biased" Line Level HiPass Filter also sounds noticably more in focus/ "or clearer,sharper" than the non-biased variety .

Biasing the caps in the high pass of the JBL DX-1 was implemented. ;)

[Guido]

After closer examination of the 2435 data I’m quite sure that the PWT 2435H frequency response shown in the AES convention paper “High Frequency components for High Articulated Line Arrays” from Doug Button was a fake. It looks much more like a 2430H :D

I was always wondering about the limited HF response. Well this is clear now. Interesting that none of the experts realized it.

OK! The REAL 2435 looks soooo good but should be out of budget for most of us.


2431
What makes me worry with the 2431 is the resonance peak at 12,5 kHz. Could this be the reason for the harsh sound? What can we do here? Does resonance compensation in that high frequency ranges make sense? Next prob is the high Fs.

2430
The 2430 looks similar to a 2426 in PWT condition but will bring no real HF improvement. Impedance is also similar to the 2426 too

[4313B]

After closer examination of the 2435 data I’m quite sure that the PWT 2435H frequency response shown in the AES convention paper “High Frequency components for High Articulated Line Arrays” from Doug Button was a fake. It looks much more like a 2430H :D Not knowing what the conditions were I have no comment.




2431


What makes me worry with the 2431 is the resonance peak at 12,5 kHz. Could this be the reason for the harsh sound? What can we do here? Does resonance compensation in that high frequency ranges make sense? Next prob is the high FsDo your measurements on the horns you plan to use and make your determinations accordingly.

[Earl K]

2430
The 2430 looks similar to a 2426 in PWT condition but will bring no real HF improvement. Impedance is also similar to the 2426 too

- As just pointed out, I'd likely be more interested in the 2430 ( in a quasi two-way ) because of its' lower resonance point ( heavier diaphragm ) and design parameters that seem to be closer to those of the 2426.
( I'd accept the ability to better handle midrange frequencies below 1K in trade over having that last octave of über UHF reach. Widgets' going to tell us to use a tweeter past 8.5K, anyhow :p )


- I'd be more interested in the 2431 ( in a quasi three-way with 8s' or 10s' below the horn driver ) because of its' higher resonance point ( lighter diaphragm ) and design parameters that are meant to achieve some form of UHF extension

- I suspect I might find the lightest weighted diaphragm of the 2435 unacceptably "underdamped" for HiFi use. ( That would be an expensive discovery to realize that I want an aquaplassed diaphragm )


- Great to see all this info , BTW . ;)

[4313B]

Note that the 2431 is the same as the 435AL as used in the Consumer 4348 (http://manuals.harman.com/JBL/HOM/Technical%20Sheet/4348%20ts.pdf).

[Guido]

[QUOTE=Giskard]Not knowing what the conditions were I have no comment./QUOTE]

You are right ;)

And if it was a fake it was a clever one.

[Zilch]

2431H "harsh" sound? To the best of my knowledge, only Mr. Widget has said that, and he heard them here in my garage, not mounted in a system, on a SR crossover, hardly "optimum" conditions.

The only other comment I have seen in this forum is that they are "smooth" in comparison to 2426H in a SR system (I forget which one).

For me, after extensive testing and comparisons documented here, I cut them into my L200's, and I can assure you all that was not because I found them "harsh." Neither did I do that impulsively; they sound damn good to me, is what, and I have invited forum members to come here with their "test" CD's and listen.

They now await "fine tuning" of the crossover based upon the forthcoming work of Guido and others. As you see above, I've built biased networks for them as Giskard and Guido suggested as a first refinement, and an improvement in VHF clarity is immediately apparent.

Let's wait for CLIO results on PT waveguides, as Giskard suggests, and proceed from there. I don't think we can conclude anything, good OR bad about them, until more of us have tried them.

Guido: The 13 kHz "resonance" peak is certainly not apparent on the impedance curves I ran this week using WT2 both on the raw driver and with it mounted on PT-F waveguides (above). It's "messy" up there, for sure, but no peak of any magnitude stands out. Perhaps they have refined the design since those early findings three years ago.

Just to confirm, here's a high-resolution sweep I just ran (70 data points) through the area of interest on the same driver on PT-F horn. WT2 does not find any impedance anomalies there:

[Guido]

2431H "harsh" sound? To the best of my knowledge, only Mr. Widget has said that, and he heard them here in my garage, not mounted in a system, on a SR crossover, hardly "optimum" conditions.

Guido: The 13 kHz "resonance" peak is certainly not apparent on the impedance curves I ran this week using WT2 both on the raw driver and with it mounted on PT-F waveguides (above). It's "messy" up there, for sure, but no peak of any magnitude stands out. Perhaps they have refined the design based upon those early findings three years ago....

COOL! This is good to hear. All parts for biased AM... Networks are waiting here. Drivers will be ordered soon. I can't wait till you come up with the measurements.
This thread is FUN! YEAH!

[spkrman57]

I digested what I could and hope to understand more as I go.

Great thread!

Ron

[Guido]

Just to confirm, here's a high-resolution sweep I just ran (70 data points) through the area of interest on the same driver on PT-F horn. WT2 does not find any impedance anomalies there:

OK! If so, I see no problems. This 1 or 2 Ohm "peak" aroung 1.8 kHz should not be a problem. That's why JBL do not use impedance correction in the AM6200 network.
I ran a few tests with my spice programm for the 4348, 4338 and S4800 today. They use impedance correction around 1.8 to 2 kHz which should be nesessary from the horns these systems use. They also use the 435AL as Giskard pointed out. This 435AL have the larger backcap. Crossover in 4338 is 700 Hz in S4800 is 900 Hz.
Zilch, try them on the 12" x 12" horns and change the 1,7uF / 0,6mH combination to 1,5 uF / 0,8mH or 1 uF / 1mH. This should improve the area around 1 kHz and match them better to the 2235H crossover of the N3134.
Tell us what this sounds like :bouncy:
If we load them too low we need larger backcaps. As the 4338 shows, its possible.

[Zilch]

Gotta order up some parts here, apparently.

Let the tweaking BEGIN! :bouncy:

[Good thing I built non-biased crossovers first.... ;)]

[Zilch]

At 3.38 cu.ft., Citation 7.4 (here with LE14H) appears "diminutive" next to B380's. Constructed of 1" MDF all around and beastly heavy, exterior dimensions are nominally 24" X 20" X 16.75" deep. Actually, this one is 24.125" X 19.875" X 16.75".

[B380 = 27.5" X 20.75" X 17" D. Port = 4" X 9"]

Port tube removes easily for measurement and photographing. It's tapered from 4" down to 3.75" inside, and flared on both ends. 9.188" overall, I'd call it 8.75" nominal port length. That's an MDF ring with an inside radius professionally glued on to the end of it, there.

Y'all KNOW where this is goin', now, I betcha.... :p

[4313B]

I guess I am not surprised that your Citation 7.4's are different than mine.


Y'all KNOW where this is goin', now, I betcha.... :pYep. Hopefully you have some 2425's or 2426's to go with them. Specifically, 2344A/2425H/LE14H. :D

[Zilch]

I guess I am not surprised that your Citation 7.4's are different than mine.Please tell us in what respects yours are different, so that we can focus in on a design. Alas, I have but one Citation 7.4, but will have to build anew, in a different baffle layout, to accommodate the HF, anyway. A pic'd be good, if you still have some....


Hopefully you have some 2425's or 2426's to go with them. Specifically, 2344A/2425H/LE14H. :DActually, I'm pickin' up a mint pair of 2425H tomorrow. I SUPPOSE I could be convinced to part with them, since I already have an array of other HF drivers here.

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.... :D

They sound kinda "rubbery."

[Just KIDDING, gang. :p ]

[4313B]

The port was different. Probably an older version. Same taper but not flared on either end. I want to say it was 8" long.

Vas is utter hell to measure properly. Take ten runs and average them.

Yes, the LE14H-3's do sound "rubbery".

[Zilch]

:hmm:

WinISD says this box is tuned to 30 Hz with 4" by 8" port, and 2 X 3" dia. 10" long ports would be equivalent. I want two ports for optimum baffle layout and user tuning options.

It also says if I use 2 X 3" X 7.375" ports, it'll be tuned to 4430's 34 Hz, and plugging one of those ports will drop it to 24 Hz (Vent mach = .22, tho). I very much like the "pick yer bass" (tight vs. extended) option of plugging one port.

WT2 says it's somewhere between 26 and 29 Hz so far. Though 30 Hz is not a bad tuning for the application, I thought Citation 7.4 was tuned to 26 Hz like B380.

What's BB6P say, please? Any recommendations?

[4313B]

I thought Citation 7.4 was tuned to 26 Hz like B380.No, the Citation 7.4 was tuned to ~ 29 Hz.

Run an impedance curve on your driver/box from 20 Hz to 40 Hz (20 data points) and post it. :)

Box with either port.

[Zilch]

It took 10 Hz - 50 Hz sweep to get both peaks, actually. Zmin is at 25.7 Hz, and the two peaks are at about 13.6 Hz. and 47.5 Hz. Saw the "20 points" too late; did 192. :p


Not a box test, just an arbitrary sweep, but WT2 would call the tuning ~30 Hz, from those numbers. :)

Actually, I'm gonna run a box test on that woofer after lunch, so I'll update with what WT2 actually finds.

Gotta move the box in from the garage first. I don't think WT2 is much liking 50 feet of wire running to box tests out there....

I think we've got it pretty much nailed, tho. Now the question is what to actually build. :D

Seems like 29 Hz is a good tuning for any of the LE14's. Maybe I give up on my "pic yer bass" option on this one.... :(

[4313B]

I think we've got it pretty much nailed, tho. Now the question is what to actually build. :DAs far as what? Volume? Tuning?

Zmin is at 25.7 HzAccording to JBL's calculations that would indicate a Vb of 4.45 cu ft. Anyway, whatever... use WT2 to test the loss factor.

[Zilch]

Use WT2 to test the loss factor.The Qloss is running in the 5 to 7 range, depending upon how nasty the noodle. :p

We've nailed the tuning of Citation 7.4 as ~29 Hz. The question is, with that size box, what's an appropriate tuning for using the array of available LE14's to make two-ways with compression drivers on constant-directivity horns/waveguides a' la 4430, 4425, etc.

I'm testing and measuring the available array here, and as soon as I'm confident with the results, I'll report the parameters and performance as found. Vas, as you point out, is a bugger. WT2 measures alpha, as I understand it, and calculates parameters such as Mms. I'm retesting everything with vented-box Vas determinations. I'd LIKE to think I had a handle on the differences among the variety of LE14's here before concludin' anything. ;)

[Thinkin' 29 Hz ain't a bad starting point, since I don't have to actually DO anything but replicate the box....]

[4313B]

Ok. You could probably tighten up that box a bit and get the QL up to around 10. Mine typically run between 10 and 15. The better stock JBL boxes are around 10. Dump the noodle and get some decent gasket material. :p

You might want to just stick with the stock Citation 7.4 volume/tuning.

I'm going to try my 2344A/2425H/LE14H combo in something slightly larger than a 120Ti sized box but that's just me. I'm going for minimal size and am willing to trade bandwidth for it. Something like ~ 2.0 cu ft tuned to ~ 30 Hz.

[mike.e]

Ok. You could probably tighten up that box a bit and get the QL up to around 10. Mine typically run between 10 and 15. The better stock JBL boxes are around 10. Dump the noodle and get some decent gasket material. :p

You might want to just stick with the stock Citation 7.4 volume/tuning.

I'm going to try my 2344A/2425H/LE14H combo in something slightly larger than a 120Ti sized box but that's just me. I'm going for minimal size and am willing to trade bandwidth for it. Something like ~ 2.0 cu ft tuned to ~ 30 Hz.
Giskard: WIth a nice overdamped response like that,and correspondingly better step response - The 'boomy port' syndrome should dissappear and sound more like a sealed box.

If the frequency response looks like a sealed box,it will sound like one right?

With my 2226 for home use i had a similar idea.

[Zilch]

All in Citation 7.4 box, AFTER bypassing its hidden internal low-pass filter. :banghead:

1) LE14A, refoamed, from S99, eBay
2) LE14H, refoamed, from L222 Disco
3) LE14H, reconed, black face (H-1 cone?), also from L222 Disco
4) LE14H-1, from Citation 7.4
5) LE14H-3, new

[Zilch]

Note: These are not near-field measurements of LF response; we're lookin' to see how they behave up to 4430 1.0 kHz crossover point. I'd say we're good to go with any of them, at least measured response-wise. New H-3's are "flattest," no?

Complete test data here:

http://audioheritage.org/vbulletin/showthread.php?p=55535#post55535

And here's a second new LE14H-3:

[Zilch]

Like this, maybe:

[Zilch]

Zilch, try them on the 12" x 12" horns and change the 1,7uF / 0,6mH combination to 1,5 uF / 0,8mH or 1 uF / 1mH. This should improve the area around 1 kHz and match them better to the 2235H crossover of the N3134.

No downward shift at 1 kHz, just a 5 dB cut from there on up. That how we're doin' this?

1) 1.7 uF, 0.6 mH
2) 1.0 uF, 1.0 mH
3) Full range

[Gotta go back and review how AM HP works, obviously....]

[Guido]

No downward shift at 1 kHz, just a 5 dB cut from there on up. That how we're doin' this?

1) 1.7 uF, 0.6 mH
2) 1.0 uF, 1.0 mH
3) Full range

[Gotta go back and review how AM HP works, obviously....]

No idea what's that at the moment :banghead:

I'll think about this :hmm:

[Zilch]

No idea what's that at the moment :banghead:

I'll think about this :hmm:Capacitance and inductance should both be going up to lower the HP frequency, no?

Why are we reducing the capacitance instead?

Giskard, can you help us with this please?

We're trying to lower the 2431H AM6212/00 HP crossover frequency from 1.1 kHz to 1 kHz so it meshes better with N3134 LP and 2235H. Not sure if that's all it will take, but it's a start....

[Zilch]

Two and a half hours with the skill saw, jig saw, and a full sheet of plywood produces "Z1" design prototype from drawing above for LE14x and PT-F waveguides, establishing final panel dimensions, bevels (missed those on the sides of the top, obviously,) and construction methodology. Approximately 3.5 cu.ft. box will accommodate 15" drivers as well, even Sub1500, probably.

I like to kick the tires before committing, and this one's a keeper. 7° front baffle rake per L200/300 and Bob's Big Boy lunch counter (a classic Googie design (http://www.googieart.com/) element). Real deal will be made of 1-1/8" stock. PM me if you want me to cut wood for you, too. Design refinement suggestions welcome.... :D

[Radius all the corners, maybe?]

[4313B]

Giskard, can you help us with this please?

We're trying to lower the 2431H AM6212/00 HP crossover frequency from 1.1 kHz to 1 kHz so it meshes better with N3134 LP and 2235H. Not sure if that's all it will take, but it's a start....Change the 1.7 uF to a 2.1 uF and see what happens.

[Mr. Widget]

I must say YOU are the king of "Quick and Dirty"... I could never do this in a few hours.... I am sure it'll tell you plenty about the prospects of the design...but then I couldn't do this either.

[Mr. Widget]

It took me 10 hrs to only get this far...:banghead:

[Zilch]

I am sure it'll tell you plenty about the prospects of the design...but then I couldn't do this either.What, forget to bevel the top, there?

Easy. It's compound, and it was lunch time. ;)

[Guessin' Mr. Widget don't need me to come over and help him with HIS cabinets.... :p]


Change the 1.7 uF to a 2.1 uF and see what happens.Will do. I think i have some 0.39 uF's I can add here.... :)

[Robh3606]

It's begining to look like there is no "Quick and Dirty 4430"

Rob:applaud:

[Mr. Widget]

Yeah.... maybe this thread should be renamed the "Meandering Quick and Dirty Two-Way Speaker Thread".

:rotfl:

Widget

BTW: I am impressed by the get up and go you have for tackling things that are frequently considered somewhat daunting. I would have spent a day just calculating the angles for those joints.

[Zilch]

It's begining to look like there is no "Quick and Dirty 4430"

Rob:applaud:We're gettin' close....

:p

[DRG]

This thread has been closed at 450 posts due to length.

Please go to Quick & Dirty 4430-Inspired Two-Ways Part II (http://audioheritage.org/vbulletin/showthread.php?t=9746) to continue with this topic.