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Zilch
11-30-2004, 02:25 PM
1) Take B380 w/2235H set vertically on "foot"
2) Mount 2344A w/2426H/J on top
3) Cross @ 1 kHz w/CD compensation (M552)
4) Biamp

Something I'm missing here?

stevem
11-30-2004, 03:36 PM
No, I think you got it. I have something similar I want to sell. Its a 2235H in a veneered 5 cu ft vented enclosure, with a 2426H and 2344A perched on top. I also have high quality cloned passive crossovers (big air core coils and PP caps). Any idea where I can find a buyer (besides ebay)?

Robh3606
11-30-2004, 04:24 PM
3) Cross @ 1 kHz w/CD compensation (M552)

Yes the CD comp doesn't work plain and simple. You need an EQ in that last octave. For PA yes but not at home. The passive network compensation is simply the best alternative and it's cheap and easy to build.

Rob:)

Zilch
11-30-2004, 07:44 PM
The passive network compensation is simply the best alternative and it's cheap and easy to build.The schematic is here:

http://www.jblproservice.com/pdf/Studio%20Monitor%20Series/4430LR.pdf

I see the subject MF attenuation (L-pad R202 and series R4) and HF bypass (R201 et.seq., 13.5 kHz?) Curiously, in biamp mode, a first-order filter (C7, 20uf, 1000 Hz?) switches in in lieu of second-order (C11, L2) internal passive mode filter. C7 merely provides phase inversion with external crossover, no?

The conjugate filter stays in the LF circuit, as well. Hmmmmm.

The 4430 spec sheet says use 5235 with special board, or, if not, 12 dB/octave at 1 kHz.

Any insights here? Haven't I also seen 5234A with 4430 boards, or are those DIY?

Robh3606
11-30-2004, 08:01 PM
Hello Zilch

Ian had a couple of good post's in this thread have a read.

http://audioheritage.csdco.com/vbulletin/showthread.php?t=1337&highlight=4430+crossover

That 20uF is one of the poles in the filter and is neccessary when used with the JBL crossovers. The cards are 18db cards not the 12db you would expect. I have a 5235 with the 4430/35 cards same as the 5234 cards.

Rob:)

Zilch
11-30-2004, 10:59 PM
I do have a pair of "new" N3134 networks, which I'm going to use to convert a pair of L200's into quasi-4430's, assuming I can make the horns fit. Don't know if anybody here has tried that.

Not sure if I'll change out the LE-85 diaphragms to D8R2425 or just pick up some 2426H's to use, maybe both, for comparison. Depends on what the LE-85's are worth at the time, probably. I'm a little concerned about the baffle angle of the L200's; 2344A in 4430 tuning wants listener on-axis or above, unless that's just BS in the brochure.

Thought I'd try this proposed B-380 "stack," as well. Mackie M1400i has "Constant Directivity" compensation that seems to match what Giskard and Ian posted as being required. JBL M552 has something similar, though I haven't seen the curves yet:


"Constant Directivity horn pre-emphasis allows for smooth, flat frequency response from JBL 2360 Series and 2380 Series Flat-Front Bi-Radial horns, or other CD horns."It's 24 dB Linkwitz-Riley filters. We'll see. Gonna take an RTA to assess what's going on with these "projects," probably.... :rolleyes:

Robh3606
12-01-2004, 07:25 AM
Hello Zilch

That's a cool idea. You are going to need a 1" spacer board under the 2344 to give it the same baffle alingment as a 4430. I use the M553 with my 2344's and the curve you get is listenable and measures fairly well but after 10K you get a good bit of roll off. The passive network does a better job up top and gives you a way to trim the response which you won't be able to do with the canned CD curve in the M552/553. The Le-85 should work fine figure the original 4430 had 2421's in there. You could go with the 2421 diaphrams but they are rather expensive.

Rob:)

Mr. Widget
12-01-2004, 10:11 AM
Hello Zilch

That's a cool idea. You are going to need a 1" spacer board under the 2344 to give it the same baffle alingment as a 4430.
Well.... what about the sloped baffle? I personally don't think the "Time Alignment" is what makes the 4430s sound good, so it probably won't matter.

Widget

Ian Mackenzie
12-01-2004, 01:53 PM
The 1'' baffle space optimises the smooth crossover transition at 1k Hertz.

Ian

Zilch
12-01-2004, 01:54 PM
The passive network does a better job up top and gives you a way to trim the response which you won't be able to do with the canned CD curve in the M552/553.So, is biamping 4430's a worthwhile endeavor at all if you need that passive EQ for the VHF that's in the network for it to work optimally?

And, if so, is there a preference for 5234, 5234A, or 5235 to use with the 4430 cards to do it? Those are 18 dB cards, as I understand it, plus the 1 pole the remains in the passive, makes 24 dB filters, which will be different, at least, from the straight passive use. Enough so to matter?

I've certainly seen posts here attesting to 4430's REALLY shining when properly biamped, tho I've never done it myself. I like 'em plenty good just running passive.... :)

Zilch
12-01-2004, 02:06 PM
I have something similar I want to sell. Its a 2235H in a veneered 5 cu ft vented enclosure, with a 2426H and 2344A perched on top. Post 'em here in "Marketplace" first with some nice pics. The forum is getting regular traffic these days....

Mr. Widget
12-01-2004, 05:12 PM
The 1'' baffle space optimises the smooth crossover transition at 1k Hertz.

Ian Agreed. If measured from the correct listening height.

My point was that since the L200 cabinet has a sloped baffle it changes the relative distance between woofer acoustic center and HF acoustic center.

Come on Ian, keep up.:D

BTW how is the crossover coming?

Widget

Ian Mackenzie
12-02-2004, 01:57 AM
The 443X are designed for a 15 degree upward tilt on verticval polar axis for inverted mounting, according to my rather dog eared white paper.

Zilch, some tweeking will be needed and access to a gated test set to result in the smoothest transition in the crossover region. The JBL network was optimised for that driver layout only.

Regards the tilted baffle why not if you wish, the design is supposed to give even power response on a 100 degree arch.

The biamping can be done with other than the 5234/5 JBL networks if you like bi amping but be prepared to fiddle a bit. If you use the JBL passives it would be a good place to start imho
.

Either way it will be vastly superior to the L200 combination.

You are in for a treat.

Ian

PS. The Widget or John F should start carving Bum horns, and if theres a demand I will make a hi fi crossover and mini class A amp for the 2426/2344 and retire..LOL

Zilch
12-02-2004, 09:40 PM
The Le-85 should work fine figure the original 4430 had 2421's in there. You could go with the 2421 diaphrams but they are rather expensive.Indeed, the mighty Giskard suggested in an earlier thread, (the genesis of the L200/4430 conversion idea):

"Change the diaphragms to D8R2421's or D8R2425's and let 'em rip." :D

2421's are diamond surround aluminum, and 2425's are titanium?

What's the difference between 2425 and 2426 drivers, then?

M552 bought on eBay came today, sans manual of course. It appears the "Constant Directivity horn pre-emphasis," whatever it actually is, is there whether you want it or not; I don't see any way to switch it in and out.

Anybody gotta M552 manual they'll copy for me so's I don't have buy one from JBL?

Thank you Ian for the encouragement. If I can work all of this out, converting L200's into quasi-4430's may be a good option for others here. I'm gonna be tryin' the P-Audio horns, as well, as soon at TimG and Widget test them. Guido's earlier work here indicated they were a viable, if not superior, alternative to 2344A's. Thinking I may bring in a couple of skids of them so's they'll be cheap for everyone to try....

The adapter dropping them down from 1.5" to 1.0" adds a couple of inches to the depth, messing up the time alignment, probably. With 24 dB/octave filters, it may not matter. What the Hell, we'll figure a way to tweak it, if necessary. As Widget suggests, it may be only a minor factor in what we like about 4430's, anyway.... :)

Charlie4350
12-02-2004, 09:57 PM
Anybody gotta manual they'll copy for me so's I don't have buy one from JBL?
[/QUOTE]I have the 552 manual and could make a copy and fax it if you like.
chuck

Zilch
12-02-2004, 10:01 PM
I'll PM you the details.... :)

Ian Mackenzie
12-03-2004, 01:32 AM
I think P Audio make a 1 inch version



Ian

Guido
12-03-2004, 03:34 AM
I think P Audio make a 1 inch version

Ian
No, only 1,5" available!

I think they where a little concerned with copyright issues :cool:

Robh3606
12-03-2004, 04:58 AM
Well the 2426 has a horn mounting plate that unscrews so it can take a threaded horn like the 2342. Other than that???? Here are the key pages to set up the crossover with.

Rob:)

4313B
12-03-2004, 08:43 AM
Anybody gotta M552 manual they'll copy for me so's I don't have buy one from JBL?It was scanned last night and should be up later today under Vintage Product.

*****

http://www.jblpro.com/pub/obsolete/M552%20Owners%20Manual.pdf

Zilch
12-03-2004, 11:33 AM
This forum's got the POWER, apparently.

I am now "Qualified Service Personnel" authorized to remove the cover.

WHOA, lookie there: A little toroidal power thingie! :D

O.K., "pre-emphasis for 60-Series horns" it is.

I'll try it on the "Quick & Dirty Stack" first.

Lookin' like the L200/4430 gonna be passive for starters, since I have the 4430 crossover. Lotsa good options here, now....

Zilch
01-22-2005, 11:33 PM
B380's brought up from the dungeon; I'm given to wonder why previous owners thrashed them so badly. Probably because they're beasts: 20-3/4" x 27-1/2" x 17" deep, i.e., 4.5 cu.ft. with a single 4" port 9" deep. Brochure says 70 lb. shipping weight; they ain't much lighter net, seems.

No matter, I got them cheap (relatively speaking), and I don't have to build them (always a dubious endeavor here). Also, I did get bonus grille frames, but I've got to replace some busted mounting pins before I can use them. Do I care what they look like? Only somewhat, for now.

Instructions for building them are here:

http://www.lansingheritage.org/html/jbl/reference/technical/1983-subs.htm

Note: Port length for B380 is 9", not the 12" stated in the article. Maybe others here who have them can confirm this, in case mine are "anomalous."

On top, P-Audio PH-316 horns, as 2344A's are much too "dear" these days at $325 a pair. Not for THIS project, nope. Mr. Widget and TimG are running tests on them with various drivers. Results "soon." Guido did some preliminary work with them, which is documented here:

http://audioheritage.org/vbulletin/showthread.php?t=2519&p=22623

I choose this orientation for the B380's to keep the 2235 up off the floor as it handles mids up to 1 kHz. Let the port play down below. Fortuitously, the spacing between this horn and 2235 maintains the same 15-1/2" center distance as in the 4430. The total assembly is somewhat taller, though: 4430 is 3 Ft. from floor to top surface, whereas we're 40-1/2" to top of horn here, without base. If we boxed the horn, it'd be more like 42", taller, perhaps 44" with a base.

Too tall for the "Theater?" Set the B380's on their sides, and the center distance remains essentially the same, leaving plenty good room for Lava Lamps. :p

For the record, 4430 box is 21-7/8" x 34" x 16" deep, about 5.25 cu.ft. according to my calculations, but with lotsa bracing and blocking to support the 2426 inside there. Subtract out the horn and driver volumes, and it looks like we're playing just about the same game volume-wise here. With two 4" x 8-1/4" long ports, 4430 is tuned higher, is what. Woof!

Is there potential trouble here? We gonna trash the mids by lettin' the 2235 play lower? Where's David Smith when I need him? ;)

We'll try some of the newer horns, as well, including P-Audio's 1" version, an apparent 2342 clone, but this is the start:

Guido
01-23-2005, 04:34 AM
We'll try some of the newer horns, as well, including P-Audio's 1" version, an apparent 2342 clone, but this is the start:

I tried the P-Audio PH230 (similar to the 2342) as an substitute in the 4425. It measures nice but plays 2-3 dB louder and I noticed a lot of coloration. I'm curious about your opinion.
I liked the PH316 but didn't like the PH230.

I will have "exact" 2342 clones from a source I can't name at the moment but will post results soon.
BTW, they can produce 2344 horns as well. I think the 2344 will be less problematic from the copyright view as they are no longer produced. But I'm no lawyer and i'm absolutely not sure with this :(


http://www.paudio-europe.com/products/codici/ph-230.gif
http://www.paudio-europe.com/products/img/line_410.gif

http://www.paudio-europe.com/products/img/specifications.gif
Description
HORN
Throat Diameter (in.)
1.0
Crossover Frequency (Hz)
600.0
Nominal Coverage Angle ()
90x90
Horn Material
ABS+Glass fiber
Mount Type
Bolt-On

http://www.paudio-europe.com/products/img/packing.gif
Net Weight (kg)
0.85
Gross Weight (kg)
1.15
Pieces per carton
1
Volume (cuft)
0.46
Dimensions (cm)
25x25x21

Zilch
01-23-2005, 01:50 PM
I see now what Ian was referring to. The 2344A horn on the 4430 is mounted 1" forward of the woofer baffle, presumably to achieve time alignment. There's certainly issues here, but whether they're major or not remains indeterminate:

The PH-316 is a 1.5" horn, and using the adapter to convert from 1" to 1.5" adds several inches depth to the assembly. 1/2 wavelength at 1000 Hz is 6.78". Does offsetting the drivers 6.78" and reversing the phase effectively restore time alignment, or just make a mess? What do we line up on the drivers, the top plates?

Another option is to use a 1.5" driver mounted directly. I've priced 2447 and 2451. They're out of range here. How about 2431? It's a 3" diaphragm driver used in a buncha JBL systems, but I can't locate specs on it. Anybody have a link or know anything about it?

johnaec
01-23-2005, 03:21 PM
There's also the 2430H.

John

Zilch
01-23-2005, 04:34 PM
3" diaphragm, Neodymium magnets.

2430 is inexpensive ($246) with an aluminum diaphragm, response to 16 kHz (-3 dB) in EVO sytems, 18 kHz at -10 dB. Also used in PD series systems to 15 kHz at -3 dB. Apparent limited VHF extension.

2431 is moderately expensive ($399), used in SRX 700 series systems, where it's spec'd to 20 kHz at -3 dB. After a nasty dip around 16 kHz, it hangs on bravely thereabove. Also used in Dance, Array, Vertec and AE series systems. Titanium diaphragm perhaps?

2435 with Be diaphragm allegedly extending UHF response is HELLA expensive ($1399), more than 2451 (4" diaphragm) variants, even....

andresohc
01-23-2005, 06:29 PM
What about the 5233s with 1200 Hz FFBREQ cards. Do they have the same problems as the M552 as far as high freq EQ?
3) Cross @ 1 kHz w/CD compensation (M552)

Yes the CD comp doesn't work plain and simple. You need an EQ in that last octave. For PA yes but not at home. The passive network compensation is simply the best alternative and it's cheap and easy to build.

Rob:)

Ian Mackenzie
01-23-2005, 08:11 PM
What about the 5233s with 1200 Hz FFBREQ cards. Do they have the same problems as the M552 as far as high freq EQ?

You can try the 5233 but as Rob says the EQ is best done passively for the 2344. Depending on the woofer or mid driver some tweeking around the crossover is best for smoothest transition.

If you need I we can measure up some coils and chuck m in the mail for the EQ.

Ian

Zilch
01-23-2005, 09:10 PM
The optimum "off the shelf" approach for 2344A equivalent horns with 2426H drivers seems to be biamp with 5235 employing the dedicated cards made for 4430/35. From the instructions, it seems easy to make the special cards up if not available.

Supposedly, the same cards work with 5233, 5234(A), and 5235. 5235 has XLR inputs and outputs and a built-in configurable "bump" low-pass filter that might be kicked in to enhance the B380 bass, like BX63, looks like.

In any case, even biamping with external crossover, most of the components of the 4430 passive crossover (http://www.jblproservice.com/pdf/Network%20Schematics/3134%20Network.pdf) remain in the circuit.

While I do have a pair of these passive crossovers for experimental purposes, purchasing them to build this project is not a good option. The price is $565 apiece from JBL, if and when available. OUCH!

However, as Robh says, the circuitry is not complex, and it looks like fuctional equivalents are easily and inexpensively assembled DIY, especially if full passive operation is not required. Even at JBL parts prices, the components are much more reasonable at $96.57. Carefully shopped, a full pair could likely be built for less than even that.

Some forum members have already built them, apparently. Perhaps they'll chime in here on the subject with substitute parts lists, prices, sources and pics. :D

See also earlier 443X crossover work by Guido and Giskard using 2431H here:

http://audioheritage.org/vbulletin/showthread.php?t=2175

2431H on PH-316 horns is looking like a particularly promising configuration just now.

Progressive Transition Waveguides and OASR horns are on order here, as well. We'll see....

Zilch
01-24-2005, 10:59 AM
Did you ever complete your work cited above with 2431 and PT waveguides?

I've seen subsequent posts relating to your trying to obtain the square format 100 x 100 version.

Did you ever obtain and test them with 2431?

Can you tell us anything about 2431, like what distinguishes it from 2430?

Is that going to work better than 2426/2344A as supposed?

Guido
01-25-2005, 11:04 AM
Did you ever complete your work cited above with 2431 and PT waveguides?

I've seen subsequent posts relating to your trying to obtain the square format 100 x 100 version.

Did you ever obtain and test them with 2431?

Can you tell us anything about 2431, like what distinguishes it from 2430?

Is that going to work better than 2426/2344A as supposed?

I'm still desperately searching the square 100x100. They seem to be available in the US. One of you guys should check this.

JBL Part No. is: 338785-002 / PT-H1010HF

I do not believe there is a big difference between the 2430 and 2431. But I do not know this.

If I can get the Horns I'll buy a 2431 or 2430 and give them a try in my (not finished) 4435.

Zilch
01-25-2005, 01:07 PM
Anybody have a pair of 2507 horn/driver mount brackets (NLA) sittin' on a shelf out there?

This'd go a bit easier if I didn't have to fabricate mounting schemes for the various combinations here....

Guido: Yeah, the horns are on order here. We'll soon see if they're available to nobodys here in the U.S., even if we DO have an account.... :p

Zilch
01-26-2005, 10:25 AM
First, the reference. This is 2425H on 2344 horn, no network.

Red on axis, blue @15, green @30, purple @45

Zilch
01-26-2005, 10:46 AM
Red = on axis

Zilch
01-26-2005, 10:51 AM
On axis, Red=PH-316, Blue=2344

Robh3606
01-26-2005, 03:22 PM
Hey not bad!

They are not as uniform off axis and the last half octave is a bit down but that's damn close. It is certainly a workable alternative. Nice measurements:applaud: How do they sound can you hear any diferences as you go off axis with program material?? Any noticable diferences on axis??


Rob:)

Mr. Widget
01-26-2005, 03:49 PM
Personally I think you are being very generous Rob.

The off axis response is nothing like the 2344. They are "not bad" in the on axis department.. but as we all know the 2344 is a bit too down already in the HF dept. These are lacking even more in that area.

Widget

Robh3606
01-26-2005, 04:09 PM
'Personally I think you are being very generous Rob.'

I can see your point. I guess I am in absolute terms. All depends on how you look at it. If I was looking for a low cost alternative I would at least give them a listen. Just mail order them so you can return them if need be. Beyond the 15 degree mark things are going down hill but toed in on axis they aren't horrible and although they are changing quite a bit they beat the hell out of my Urei Horn in my center channel off axis. The Urei is a fine sounding horn on axis. Off axis it has problems but I don't use it that way and it wasn't designed to be used that way. That's why I asked how it sounded. Pink noise you would hear differences off axis in a heartbeat. Be curious on program material compared to a 2344. Also wonder how close they sound on axis. Measurements aren't the end all. Doesn't mean they don't or can't sound good, besides anyone looking at these measurements will be making their own decisions.

Rob:)

Zilch
01-26-2005, 04:45 PM
How do they sound can you hear any diferences as you go off axis with program material?? Any noticable diferences on axis??We kinda knew on inspection that they were not equivalent, because the vertical slot width on PH316 is the full 1-1/2" of the designated driver, whereas 2344A is more like 5/8", i.e., less than the 1" driver exit. I read somewhere this matters. :p

Clearly, the geometries are different. I'm thinking the PH316 may behave somewhat better with respect to directivity with a 1-1/2" driver on it rather than a 1" driver with throat adapter. We'll see.

Thus far, I've only played program material through this single PH316 with LE85 on it, and not with the 4430 network. It sounded fine, but it was clear there was HF attenuation off-axis, as the tests confirm. When the other horn gets here from TimG (who's also running tests on it,) along with his 8-ohm 2427 drivers, I'll be able to hook them all up and give the system a reasonable listen.

In the meantime, I'm trying 2426J's on 2370A horns with 3110A networks, which also have HF boost. If I recall correctly, I'll have to pad the whole works down to balance with the 2235's in the B380's. I did this combo once before in Olympus; gotta look up how much I had to throttle them to get reasonable balance. Maybe I get smart and use some 30W L-pads this time, like Giskard suggests. ;)

This'll also be the first opportunity to try the M552's CD horn pre-emphasis on for size. [Note to self: Amps are last on and first off, stoopid....] :blink:

Robh3606
01-26-2005, 05:02 PM
"This'll also be the first opportunity to try the M552's CD horn pre-emphasis on for size."

Tried that and the 4430 is better. Too much roll off actual a good bit more than the PH316 on axis with the 4430 network.


"[Note to self: Amps are last on and first off, stoopid....] http://audioheritage.csdco.com/vbulletin/images/smilies/blink.gif"

Your not kidding! The on/off is not the soft and if you forget you will be cringing. I did once damn near jumped out of my skin!!

Rob:)

Robh3606
01-26-2005, 08:25 PM
Take a look at the directivity and off axis response curves on the Urei 813 and 4330 monitor that just used the 2308 lense to set the off axis response. You can see why I think the PH316 horn is better off axis than the Urei. There is a rather obvious mistake the 4430 and 813 plots are misslabled. Just wanted to post for information for those who have not seen it. All three horn/compresion driver combo's can sound very good on axis even though there is quite a bit of variation in their off axis response curves.

Rob:)

Ian Mackenzie
01-26-2005, 09:12 PM
Great work,

The wider vertical slot will effect the horizontal dispersion , try it rotated 90 degress and see what happens.

The larger slot may afford lower distortion assuming it runs a 1.5 inch driver....Tad anyone?

Ian

Zilch
01-26-2005, 09:58 PM
Try it rotated 90 degress and see what happens.Well, d'UH! :rolleyes: :rolleyes: <---- (Zilch & Widget)

We'll plan on trying that on the next round of tests, when the other drivers and horns get here.


Tad anyone?The mounting pattern is different. Didn't want to hack up the TADs QUITE this soon. :p

[Ian thinks outside the box. GOOD stuff!!]

Just discovered JBL makes a horn adapter for using PT Waveguides with 1" drivers.

[MORE options....] :D

Mr. Widget
01-26-2005, 10:05 PM
I did think about it, but not until after I had taken the driver off and disassembled my turntable rig. Sorry. :)

Oh heck, the damn thing still needs to be used as a three-way anyway... just track down a 2344!

Widget

Zilch
01-27-2005, 10:03 PM
B380, 2426J on 2370A, 3110A. Attenuated HF 6 dB, not quite enough yet. Narrow vertical field, 40, is apparent. Not 4430's, tho, I hear the horns.

Looks nasty, plays nice, and boy, howdy, LOUD. Good choice for frat parties. HF Boost on 800 Hz 3110A network works for CD horn compensation.

I'd forgotten how superbly competent B380's are. I keep pushin' loudness compensation on just to shake the place. They don't care, they just DO it. :D

4313B
01-28-2005, 02:48 AM
B380, 2426J on 2370A, 3110A. Attenuated HF 6 dB, not quite enough yet. Narrow vertical field, 40, is apparent. Not 4430's, tho, I hear the horns.A walk down memory lane - my first non-exponential horn system.


I'd forgotten how superbly competent B380's are.I find that particular enclosure volume tuned up to ~ 29 Hz quite fantastic. I've built several custom pairs of 4430's exactly like that. It's basically Keele's "optimum" calculation for the 2235H (4.55 cubic feet tuned to ~ 29 Hz). Tuning that volume down to 26 Hz and applying the boost at Fb from the B380 is a mild assisted alignment (for a 6th order Butterworth assited alignment according to Keele one would tune that volume down to ~ 20 Hz, 29 Hz * 1/sqrt(2), and apply the high pass bump filter at that frequency). One can "cheat" with the stock 4430 by closing one of the ports and applying a high pass bump filter at ~ 24 Hz. The nice thing about the stock B380 is that it doesn't suffer much power handling loss at all above resonance like a true B6 alignment would. Probably why JBL went with it instead of trying to go solid to 20 Hz. ;)

RED = Stock B380 without BX63
GRN = Stock B380 with BX63
BLU = Stock B380 B6 tuned and assisted

Zilch
01-28-2005, 10:32 AM
I find that particular enclosure volume tuned up to ~ 29 Hz quite fantastic. I've built several custom pairs of 4430's exactly like that. It's basically Keele's "optimum" calculation for the 2235H (4.55 cubic feet tuned to ~ 29 Hz).While I have a BX63A, I've never used it with B380. Natural room response and boundary effect have always made your red curve there work for me.

I'll run the numbers to see what I need to raise them to 29 or 30 Hz. I'm not ready to shorten the ports quite yet. Maybe a rolled insert will get it. And, I'll nose around the plumbing department at the hardware store. Most of my port tuning solutions find inspiration there. Do you have any suggestions? :D


(For a 6th order Butterworth assited alignment according to Keele one would tune that volume down to ~ 20 Hz, 29 Hz * 1/sqrt(2), and apply the high pass bump filter at that frequency.)Like the Q=2 6 dB bump high pass in 5235 at 20 Hz, maybe? 5235 with 4430 cards is startin' to look like a good fit here.... :yes:

Mr. Widget
01-28-2005, 10:48 AM
I'm not ready to shorten the ports quite yet. Maybe a rolled insert will get it. And, I'll nose around the plumbing department at the hardware store. Most of my port tuning solutions find inspiration there. Do you have any suggestions? :D


I recently ran into that very problem with the Project May cabs. I tried putting dowels etc. in the ports, but after taking new measurements I couldn't get the frequency to shift predictably. I ended up cutting new ports that were shorter as I wanted to preserve the originals.

Widget

Zilch
01-30-2005, 11:45 AM
1) It seems that LE85 has about the same sensitivity as 2426 (110 dB) when mounted on Biradial horns. I thought I was having to pad down (-6 dB or more) 2426 because it was more sensitive. Turns out it was the HL91 that was eating that SPL in early LE85 designs, apparently. Izzat right? (Note: tired old LE85 sounds mighty smooth and mellow in comparision to 2426. Could be my eBay 2426's have some bad history, tho....)

2) I also erroneously assumed low sensitivity of 2235 was responsible for a significant portion of the padding requirement. It's SOME part, but not so much. Best I can determine, LE15 is 95 dB, 136A is 94 dB, and 2235 is 93 dB. Do we know where LE15B (L200) would fit in there? 96 dB, maybe?

3) I tried the CD horn pre-emphasis on the M552 crossover. As others have observed, it doesn't get it in the last octave. The 80-Series settings are better than the 60-Series, but not good enough.

4) I cannot do this without RTA instrumentation. Even a two-way with these few variables is impossible to get balanced by "ear." After a couple of hours of listening, the ear (and brain) becomes habituated to the current setup and adjustment. Next morning, I turn it on only to discover it's total crapola. Mr. Widget has generously offered to loan me an RTA for the duration. :thmbsup:

5) The two crossovers incorporating HF boost I have tried, 3110A and L200B (see pic below) work reasonably well. Can somebody run the sims (voltage drive) on the HF sections of these topologies (3110A at min mid and max HF boost) in comparison to N3134 (4430) please, or recommend what software I should use to run them?

6) N200B sounds pretty good, actually. Maybe I'll open them up and modify for biamping a'la N3134, installing bypass caps and also a rheostat in the HF bypass loop in lieu of the 5-ohms there. Do I need to change the cap in the Zobel to the 14 uF of the N3134, or just let the 8.25 uF ride? I can't believe the impedance peak of 2235 is that different from 136A. (Interestingly, the Zobel stays in when biamping 4430, but NOT when biamping 4435.) Even in detail, the topologies of N200B and N3134 are strikingly similar.

7) And in a final surprise, JBL has acknowledged my order for PT waveguides and OASR horns. Operatively, OASR (Optimized Aperture Symmetrical Radiator) will require CD compensation, no? It's 85 x 85, probably conical, from the looks of it. How low do it go? We'll see.... :p

Zilch
01-31-2005, 05:48 PM
31xxA Curves as published by JBL:

Zilch
02-04-2005, 02:00 PM
5235 came with 800 Hz 18 dB cards. From the component list in the manual, it looks like 4430 cards, actually 12 dB, are built on the 18 dB blanks with a couple of jumpers in lieu of poles. Cards are NLA, apprently.

Does anyone have a pair of 4430 cards they're willing to loan or sell to me for this project so's I don't have to tear into these? Or blank 18 dB cards, maybe?

Purdy-please?

If so, PM me to advance this endeavor.... :bouncy:

Zilch
02-04-2005, 02:42 PM
From the 5235 manual:

"Whenever a midrange or high frequency compression driver is connected directly to a power amplifier, it is recommended that a capacitor be wired in series with the driver in order to attenuate unwanted low frequency and switching transient signals, and to block DC components, any of which can damage the driver. This applies to most biamplified and triamplified systems employing compression drivers. (In conventional systems with passive, high-level dividing networks, the network comes between the power amplifier and the driver(s), so the protection is already built-in.)

Notes:

1) In all JBL monitors which are designed for biamplification, the dividing networks already incorporate the required attenuation capacitors between the input(s) and the compression driver(s).

2) Series capacitors are not required for low frequency and midrange cone or dome type transducers."

The manual specifies a 40 uF non-polarized capacitor for crossover frequencies of 500 to 5000 Hz with 8-Ohm driver, 20 uF for 16-Ohm, and a chart for more precise selection of capacitor values. Then:

"Notes:

1) The optimum value cited in Table 3 assumes that the capacitor is active at approximately one octave below the listed crossover frequency, assuring minimum acoustical interference with crossover region performance while maintaining a good degree of protection.

2) Somewhat smaller capacitor values may be required for additonal protection in high-power sound reinforcement systems.

3) To shunt the reactive component of the compression diriver's impedance below horn cutoff, a 50 W resistor having a value of two to three times the rated impedance of the compression driver should be connected across the driver's terminals.

Caution: Below the cutoff frequency of the capacitor, the power amplifier will be unterminated. If the power amplifier has an output transformer (typical of vacuum tube amps and some solid state amps designed to drive constant voltage lines,) a 20 W resistor equal to 10 times the compression driver impedance should be installed across the amplifier output terminals."

Ummmm, do we actually DO this stuff, or is it boilerplate? Do I need to insert this humungous cap in line? I assume that a capacitor an octave below the crossover frequency is not gonna alter the crossover characteristics, but do we also gotta hang a 50 W resistor across the driver terminals as suggested here for inductive reactance? I DO see banks of shunt resistors in some JBL crossover designs.... :(

Robh3606
02-04-2005, 02:44 PM
I have a pair of 4430/35 cards you can borrow to check things out. I am looking for 4434/45 cards for my 5235. Didn't want to rip into those to make them. I know how you feel. Why mess up stock cards!! Send me a PM. I can get them out on the way early next week unless you get a better offer before.

Rob:)

Zilch
02-04-2005, 02:54 PM
Thanks, Rob! Maybe we can track down some 4344/4345 cards to swap here. :D

Earl K
02-04-2005, 03:45 PM
Hi Rob / Zilch

I think that you guys could really benefit by getting in with Ians' PCB program and learning how to do "photo-resist" layouts. The actual core info is still back in his main thread ( it's about the photo-resist kit that you need to buy ). I'm gravitating this way myself for small runs of pcb cards. This way one can simply make up their own 18db cards or whatever. I think the multipin connector on the card is made by "Molex" (?) .

:cheers:

Zilch
02-04-2005, 04:05 PM
I think that you guys could really benefit by getting in with Ians' PCB program and learning how to do "photo-resist" layouts.Thank you, Earl. I'll look that up!

Very likely, we'd be able to build these on perf board, as well. Once I have the 4430 ones in hand, I'll try to replicate them.... :)

Zilch
02-05-2005, 06:47 PM
0, 15, 30:

Zilch
02-05-2005, 07:08 PM
0, 15, 30:

johnaec
02-05-2005, 08:14 PM
'Any idea of what adapter he used to go from 1" to 1.5"?

John

Zilch
02-05-2005, 08:19 PM
As I read it, Tim confirms Widget's findings: PH-316's 20 kHz response is down 10 dB at 30 off-axis horizontally, but not so bad at 10 kHz. Alas, for 4430, it's VHF that most matters.

As Ian suggested, the vertical behavior measures substantially better.

Mount 'em sideways. :D

Zilch
02-05-2005, 08:22 PM
'Any idea of what adapter he used to go from 1" to 1.5"?I sent him the same P-Audio conical tapered throat adapter that Mr. Widget used. I'm not sure if he actually used it, tho. Hopefully, Tim'll sign on and clarify this....

TimG
02-06-2005, 08:21 AM
Yes, I used the P-Audio 1" to 1.5" throat adapter that Zilch sent me to measure the horns with the JBL 2427H. I attempted to use a Selenium 1 3/8" threaded to 3 bolt adapter to attach the driver to the P-Audio adapter, but the Selenium bolt pattern was too wide to line up with the throat adapter. This adapter here http://store.steelsound.com/Detail.bok?no=428 looks like it may work with the 2427H.

I recieved a pair of the horns used in new SRX 715 last week, and I have a pair of 1" to 1.5" JBL adapters 339308-001 $19, as used in this speaker and others http://www.jblproservice.com/pdf/AE%20Series/AC2212,64-WH.pdf, on the way. I'll post results of these horns with a B&C DE25 as soon as the adapters arrive. Now that I have the 1.5" throat horns I will try to obtain a BMS 4555 driver to measure as well.

Zilch, could you post the part numbers and prices for all of the JBL horns you will soon have. I think the 12" x 12" 100 degree horn would be the most promising for home use in a 4430 style system.

Zilch
02-06-2005, 10:08 AM
Zilch, could you post the part numbers and prices for all of the JBL horns you will soon have. I think the 12" x 12" 100 degree horn would be the most promising for home use in a 4430 style system.I have 3 horns coming:

1) 338786-001 - PTF1010HF, the 100 x 100 rectangular horn, 1-1/2" throat which tomp787 is evaluating. $83 list.

2) 338785-002 - PTH1010HF, the 100 x 100 12" square horn, 1-1/2" throat, the one Guido is trying to get for his 4435 project. $84 list.

3) 126-00013-00 - the round OASR horn with 1" threaded throat, used by sebackman in his HT project. $38 list.

The 339308-001 adapter Tim mentions will allow 2426/2427 with throat adapters removed to be used with the first two "Progressive Transition" waveguides. As sebackman showed in an earlier thread, 2426/2427 will screw directly onto the OASR horn. $19 list.

I'm thinking the P-Audio 1" to 1-1/2" adapter will allow using LE-85 and other 3-bolt 1" drivers with the PT horns, and I also have some other adapters here to mess with, if necessary.

I'll post pics of this stuff here when and if it comes next week.... :p

A major outstanding question for this thread's projects is whether any of these newer horns are suitable for use down to the 4430's 1 kHz or the L200B's 800 Hz crossover points. The lowest I see them used is 1.1 kHz in JBL products.

Zilch
02-06-2005, 11:29 PM
LE-85's (alt 2426J) mount to P-Audio horns with 1" to 1-1/5" P-Audio throat adapters mentioned above. Total assembly is 9" deep from rear of LE-85 to mounting surface. These would retrofit into L200 easily, which has 12-3/4" depth, but it's a squeeze to fit this 12" x 12" horn into the approximately 13" available baffle space above the woofer there.

Run on the N200B crossovers shown, they have to be padded down about 10 dB to get into the middle of the operating range of the stock level controls. I'll get more precise with this once RTA instrumentation gets here. HF boost seems to be adequate, tho we need to generate the curves to be sure. N200B inverts the phase.

At this 800 Hz cross frequency, I could hear the 2370A horns in System A, but these PH-316's sound fine that low, and provide a substantially broader vertical field, even mounted sideways. They're cleaner sounding biamped through the crossovers with M552 (24 dB/octave), so reworking them accordingly and adding bypass caps would likely be a worthwhile endeavor.

Time to bring the L200's up from the dungeon too, probably. It looks like there's at least this one good option to resurrect them. They're about 5.25 cu.ft., with two 4" x 7-1/4" deep ports. Sound familiar? That's 4430 size. Plugging one of the ports is gonna move the tuning down nicely, so off to the local plumbing store for proprietary tuning devices. We'll see if it gets better with the newer horn options....

Note: Labels on LE-85's say "8 Ohms." They're 16 Ohms nominal, of course, measuring 6.0 and 6.4 Ohms DCR. Whatever. They work, and sound good, is what.

[Excuse the kludge. I'll clean it up later. :p ]

Guido
02-07-2005, 03:36 AM
2) 338785-002 - PTH1010HF, the 100 x 100 12" square horn, 1-1/2" throat, the one Guido is trying to get for his 4435 project. $84 list.

I'll post pics of this stuff here when and if it comes next week.... :p



And they really told you they are available??

Zilch
02-07-2005, 10:35 AM
And they really told you they are available??Hi, Guido!

Allegedly, they accepted my order and shipped complete, though they DID have a problem figuring out what I was ordering, and it took a couple of phone calls to make it happen. We'll see this week.

From what I understand, these items are not available for sale as components, and there is only limited (if any) stock for replacement parts. Otherwise, they have to pull from their production stock and order anew to replace it. That's why they're hard to get -- we give their inventory control fits purchasing this stuff in any quantity.

If they actually come, I'll be posting pics here. Then I'll gloat for a day or two before ordering up some for you if you want them and can't obtain them direct. I doubt they're on the Department of Commerce "Prohibited Technology" list. :D

I'd be real interested to see the results of your evaluating them with 2431H. I'm planning on doing that, too, as well as running 1" drivers (LE-85, 2426/7) on them and the smaller rectangular version, which may fit L200 cabinets better than the 12" square format. From my experience with 2370A horns, though, I doubt the smaller PT waveguide will reach down to the requisite 800 Hz for an L200B swap comfortably.

We're gonna need to develop the optimum HF boost crossover topology as well, as you know....

Zilch
02-07-2005, 01:54 PM
Looks wrong, sounds good. P-Audio PH-316 on LE-85's using N200B crossovers, padded down. Choose horizontal beamwidth by rotating the horns. Here, W-I-D-E. Thanks Ian, Tim, and Widget. I think we've got the P-Audio horns figured out. :p

4430's? Nope. Not yet....

4313B
02-09-2005, 11:38 AM
5) The two crossovers incorporating HF boost I have tried, 3110A and L200B (see pic below) work reasonably well. Can somebody run the sims (voltage drive) on the HF sections of these topologies (3110A at min mid and max HF boost) in comparison to N3134 (4430) please, or recommend what software I should use to run them?3110A voltage drive simulation courtesy of David Smith. :cheers: 08-FEB-2005
You should already have my 4430 and 4435 voltage drive sims.
They've been posted several times.

Zilch
02-09-2005, 01:49 PM
3110A voltage drive simulation courtesy of David Smith. :cheers: 08-FEB-2005Way COOL! Ontogeny recapitulates phylogeny here, apparently.

Yup, I have the 4430/35 sims. How about N200B? Izzat available anywhere?

Zilch
02-09-2005, 01:52 PM
Oh! Yeah! You guys have alot of those LE85/2420/2421B/2425J drivers laying about that need using?Yeah, a primary objective is to convert L200 and/or L200B into "Quasi" 4430, which means work with the LE85's that come with.

We have some 4430 crossovers, but perceive it'd be cheating (and somewhat inelegant) to just rip everything out and put in stock 4430 replacements. And buying or building N3134 xovers is not a viable option for most folks. 2344A horns may not be, either.

The other primary objective is to "sweeten" 4430 with newer driver and horn technologies, if possible. In the course of trying that, we may come up with some even more feasible options for L200/B. :D

4313B
02-09-2005, 05:10 PM
How about N200B? Izzat available anywhere?Only with the L-Pad wide open. Measure a 16 ohm L-Pad set at 50% for me. I don't have any laying around right now. 1 to 2 and 2 to 3. Measure a couple of them.

Zilch
02-09-2005, 05:21 PM
Gotta unsolder here. Hang on.... :p

L-Pad #1: 1-2 = 16.7, 2-3 = 8.1

L-Pad #2: 1-2 = 16.4, 2-3 = 8.0

Hmmmm. -6 dB nominal, looks like.

These are 50W Parts Express ones.

You want the 30W ones in the actual crossovers?

[Wonders whether different "ranges" are available to OEMs, or just one standard throughout....]

Not the same. In the crossover itself:

L-Pad #3: 1-2 = 33.4, 2-3 = 6.2

L-Pad #4: 1-2 = 34.0, 2-3 = 6.0

~-4 dB nominal, maybe.

Old school assemblers wrapped them wires through the eyelets. ;)

4313B
02-09-2005, 05:22 PM
Yep, gotta be out of the circuit.

Thanks!

4313B
02-09-2005, 06:30 PM
N200B Voltage Drive. Yellow is L-Pad wide open. Cyan is L-Pad at 50%.

Zilch
02-09-2005, 07:48 PM
Y'know, I could hear N200B sounded better in it's lower operating range. It's why I added the external L-Pad to adjust the balance between the horn and the 2235H. If I crank the network's L-Pad full open, the HF boost is gone, as indicated above.

3134 & 3135 voltage drive Giskard posted earlier:

Zilch
02-09-2005, 08:03 PM
O.K., so help me interpret and understand this, please.

Looks like they're all three the same game, essentially, but 4430 has 5 dB more boost (not insubstantial).

N200B could/would have more than 3110 if it were operated at, say 25% rather than 50%. (Gonna resolder stuff and try that.)

N200B level control adjusts the highpass Q, apparently, within limits. While not intended for CD compensation, it might be successfully used for that purpose.

Special thanks to Giskard for the requisite curves.... :)

Zilch
02-10-2005, 02:01 PM
"Real deal" 2344A horns provided for this project by forum member Mike Caldwell have engineered constrictions in the diffraction slot to transition from 1" round to race-track oval narrow (~5/8") opening in horn shown below. I haven't found the JBL reference again yet which describes the essential purpose, alas. I CAN, however attest that there's an immediately apparent difference between the performance of PH-316 (which doesn't have it) and 2344A (improved dispersion and transparency).

The OASR tech note touts the lowered distortion advantage of NOT having such constriction, however. PT Waveguides apparently continue that diffractionless design philosophy.

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

http://www.jblpro.com/PD5000/PDF/PT_WaveGuide.pdf

Robh3606
02-10-2005, 02:16 PM
This explains it pretty well

Rob:)

Robh3606
02-10-2005, 02:21 PM
Now the other view. Your cards are in transit.

Rob:)

Zilch
02-10-2005, 02:23 PM
O.K., 0.7598" then. :D


Your cards are in transit.

Oh, BOY, we'll have ALL the pieces soon! :bouncy:

Ian Mackenzie
02-10-2005, 04:28 PM
That White paper is a good read.

I spent 12 months trying to make the passive crossover eq from the simplified schematic in the paper before emailing JBL and asking for the schematic (before it was public domain) which they actually send me.

I have it that the Tad 2001 works very nicely on this horn with some tweaks to the eq.

Ian

Zilch
02-10-2005, 09:11 PM
Depth is 7" from rear of driver to mount surface, approaching alignment with woofers, so polarity is re-reversed when connected to L200B crossovers. In this setup, 2344A is operating at its lowest recommended crossover frequency, 800 Hz:

http://www.jblpro.com/pub/obsolete/2344A.pdf

Zilch
02-10-2005, 09:18 PM
Real deal (albeit funkified) 2344A horns, here with LE85 and L200B crossovers. N200B L-Pads set to 20% (9:00) position for presumed maximum HF boost, LE85's are still attenuated an additional 3 dB with an external 16-Ohm L-Pad. Quite listenable, getting close..... :)

Zilch
02-12-2005, 02:24 PM
Inexpensive ($38) floriform JBL OASR horns (85 x 85) are thread-on mount, 1-3/8"-16. Removing adapter on 2426J (not easily accomplished on one of them; had to use lathe chuck and oil-filter wrench) exposes threaded "snoot." LE85 is easily adapted using P-Audio PC-35 throat adapter, shown.

Surprisingly, the relatively small (8-3/4/" square) OASR horn assemblies are deeper than 2344A behind the panel by about 1". I have no clue what these are (CD or not?), or the requisite equalization, until Mr. Widget measures them. They sound "tweety," which may be good. :p

Clearly, LE85 does not conform to the "Optimized Aperture" design guidelines:

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

It's not clear that 2426 does either, for that matter. What, then? 2406 or 2407? This "Optimized Aperture Symmetrical Radiator" is used in Marquis 112 (http://www.jblpro.com/pub/obsolete/Marquis/ms112.pdf) with 2418H crossed at 1.6 kHz, Marquis MS28 (http://www.jblpro.com/pub/install/marquis/ms28.pdf) with 2412H at 2.8 kHz (MTM center anyone?), Sound Power SP 212-A (http://www.jblpro.com/pub/obsolete/Sound_Power/sp212-a.pdf) with 2426H crossed at 1.6 kHz (nice response curves!), smaller SRX Series (http://www.jblpro.com/srx/srx_product.htm) monitors with 2417H (1.2 kHz) and 2226H (1.3 kHz), CSP18 (http://www.jblpro.com/pub/cspels/CSP18.pdf) with 2418H, unstated crossover frequency, here called a "Conical Waveguide," and unknown others, perhaps.

[Note: Order gaskets for these as well to use as mounting template. NOT a round hole.]

Zilch
02-13-2005, 06:52 PM
OASR under test at Widget Works. Comprehensive tests and measurements with different drivers take less than an hour using CLIO system:

Mr. Widget
02-13-2005, 08:47 PM
So how do the relatively inexpensive OASR horns sound? I couldn't tell you.:) They do measure pretty well on axis though don't quite have the off axis response of the 2344. Here is a plot comparing the on axis response response of the 2425 on a 2344 and a 2427 on the OASR horn.

Red 2344
Blue OASR

Mr. Widget
02-13-2005, 08:53 PM
Both of these sets of plots are using the CD (constant directivity) equalizing network from a 4430. The Upper plot shows the on and off axis response of the OASR with 2427. The lower is a 2425 with 2344 horn.

For both sets of plots.
Red is on axis
Blue is 15 off axis
Green is 30 off axis
Purple is 45 off axis

Mr. Widget
02-13-2005, 08:58 PM
Here is a plot with no compensation comparing both the LE85 and the 2427 on OASR horns.

Red is LE85
Blue is 2427

Mr. Widget
02-13-2005, 09:00 PM
Here is a plot of an LE85 both on and off axis. Again, there is no compensation so we see the actual roll off of the horn.


Red is on axis
Blue is 15 off axis
Green is 30 off axis
Purple is 45 off axis

Mr. Widget
02-13-2005, 11:04 PM
Based on these measurements, I'd like to see a bit more top end, but as a mid horn between 1KHz and 10KHz, this may be just the ticket for a low cost solution. We will have to wait for a subjective evaluation.

Widget

Zilch
02-13-2005, 11:40 PM
We will have to wait for a subjective evaluation.We will ALSO provide refreshing beverages.... :cheers:

Thank you again for your excellent contributions to this quest! :applaud:

[More horns and drivers are on the way. Heh, heh....]

Zilch
02-14-2005, 02:44 PM
More info from the forum about the subjects at hand here:

http://audioheritage.org/vbulletin/showthread.php?t=4731

http://audioheritage.org/vbulletin/showthread.php?t=1159

http://audioheritage.org/vbulletin/showthread.php?t=2226

Still looking for Giskard's referenced "I believe I've posted the ranges for the L-Pad and potentiometer in the 4430 elsewhere on the forum." Anybody know where?

4313B
02-14-2005, 03:06 PM
Old graphics posts

Zilch
02-14-2005, 03:39 PM
Izzat BEAUTIMOUS or WHAT? :applaud:

[Thinkin' 3110A and N200B are not TOO far off of that, after all, as documented above....]

Gonna unsolder again and generate some more detailed N200B L-Pad readings....

Note: Hooked up N3134's with L-Pads set according to foilcal, and RTA Widget loaned me said they were spot on.

It's surprising how little program content there is at UHF or below 31.5 Hz, actually.

B380's did pump out 20 Hz boom at the end of Pink Floyd "Pulse," tho.... :D

Biamp cards for 5235 aren't here yet, but a quick try with M552 24 dB filters yielded impreceptible improvement, if any.

Gotta do more "critical listening," apparently.... :blink:

RTA is plenty good fun!

The most gorgeous graphic ever posted on the forum, I'm gonna print that one and frame it! :p

[Card is 52-5130, tho, I believe....]

4313B
02-14-2005, 03:55 PM
Green is 4430 with pads open

Yellow is 4435 with pads open

Cyan is L200B with pad open

Zilch
02-14-2005, 04:09 PM
From the schematic (and listening), N200B max boost (steepest slope) should be at about 20 or 25% L-Pad setting. At max, the slope is flattest, actually. I gotta get you the real numbers for the settings, is what....

The objective is to approximate the cyan curve (4430 set flat) using N200B to get the desired HF boost, then adjust the balance with 2235 using an outboard L-Pad attenuator. There seems to be plenty (~4 dB extra) drive left over, even with the N200B pad throttled down as proposed.

See 50% N200B setting here:

http://audioheritage.org/vbulletin/showthread.php?t=3838&p=42483

Robh3606
02-14-2005, 04:40 PM
You should get the card tommorow. How's the hunt going??

Rob:)

Zilch
02-14-2005, 04:46 PM
Hi, Rob!

Looks like Mick never came back on. I sent him a PM, but his eMail is private. Unless he logs on, he won't know about the PM if he doesn't have eMail notification enabled, which is doubtful.

I'm about to ask Don to send him a little "heads up," probably.... :p

Maybe you PM him too?

4313B
02-14-2005, 04:47 PM
[Card is 52-5130, tho, I believe....]The 52-5130 is the stock card for the 4430/4435. You have to build your own using the 51-5130 schematic as the stock 4430/4435 card isn't available anymore.

Here's the values for those who don't feel like looking them up ( me :p ).

Zilch
02-14-2005, 05:11 PM
Here's the values for those who don't feel like looking them up ( me :p ). Yup. Only one R-C time constant remains in the HF feedback circuit, C4, R4. 5235 manual calls it a "12 dB" card, though it's built on the 18 dB board, apparently. They all the same board, no? That is, ANY of the 18 dB boards could be stripped and converted to 4430/35, it would seem?

Robh3606
02-14-2005, 05:37 PM
"That is, ANY of the 18 dB boards could be stripped and converted to 4430/35, it would seem?"

Yes

Rob:)

Zilch
02-14-2005, 11:13 PM
Setting = terminals 1-2 each unit and then 2-3 each unit

7:00 = 0.0, 0.1 - 13.2, 12.9
8:00 = 5.4, 5.4 - 11.6, 11.4
9:00 = 12.7, 13.1 - 10.2, 9.9
10:00 = 18.7, 18.2 - 9.0, 8.8
11:00 = 24.9, 24.8 - 7.7, 7.8
12:00 = 32.9, 33.0 - 6.1, 6.1
3:00 = 55.3, 53.3 - 2.4, 2.3
5:00 = 70.0, 72.0 - 0.1, 0.1

I'm providing more resolution in the area of interest, the lower half.

If these numbers suck badly, lemme know, and I'll set up something to more accurately make the settings. A busted clock anna BIG knob, maybe.... :p

4313B
02-15-2005, 06:58 AM
Green is the 4430 with both pads set to "0", the rest are the N200B set as per your values.

Zilch
02-15-2005, 09:39 AM
You are a veritable ARTIST with these stunning graphic presentations. :applaud:

These latest N200B curves certainly confirm what I am hearing here:

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=6&p=42586

It's possible that a simple reconfiguration of the N200B network (add series resistance to the MF leg, perhaps?) could get us where we want to be. The potential seems to be there. As is, they look more like the 4435 curves, in fact, but we're not going there, yet. :p

Before pursuing that further (other than to think about how to do best do it,) maybe we should wait for the new PT waveguides to arrive for evaluation. While 2344A DOES fit in L200, it's a very tight squeeze into the space above the woofer, right up against the top overhang, and the center-to-center distance from woofer to horn is off by several inches compared to 4430 (too close).

I'm thinking if the "compact" rectangular version of the PT waveguide tests well, and can be successfully mated with LE85, it may be the better choice for L200 upgrade. The crossover can then be reconfigured optimally for the final horn/driver choice.

Also, I'll work some more with the OASR horn, but it appears from Mr. Widget's tests that it simply does not have the potential for HF extension we need. It would certainly fit the L200 cabinet easily, and may itself comprise an upgrade, but I think we can do still more and better. I know several other forum members are working with it; perhaps they will offer some further insight on OASR. I have some inexpensive 2418H-1 drivers coming to try with it, as well, but have no clue what they are other than small-diaphragm HF drivers used by JBL with that horn in some systems. If anybody has specs on them, that might be helpful.

I see lotsa L200's being offered for sale on eBay of late. With upgrade, they may offer the potential for a truly good sounding system in an attractive "vintage" package.... :)

Zilch
02-15-2005, 12:52 PM
RTA (Real-Time Analyzer, courtesy Mr. Widget) with microphone on boom is an essential tool for setting up various combinations of drivers, horns, and crossovers, even with simple two-ways. While clearly not the sophisticated resource of CLIO system Widget uses, this DOD unit's multi-colored LED graphic display (top of amp stack, left) and built-in pink noise generator help get it all balanced and working together, allegedly with +/- 1 dB accuracy. I can certainly tell in an instant whether a particular combination plays within workable range. Approx. $200 on eBay.

Again, kindly excuse the dust.... :p

Zilch
02-16-2005, 02:00 PM
JBL crossover cards for biamping (courtesy robh3606) plug onto 5235 motherboard, though not without struggle. Even getting the bottom cover off is tough (at least for the anxious Zilchster, after dark :p ). Then, as shown, the cards are retained on captive standoffs, and the connectors are snug. Rugged, so there's little likelihood of damage, it's still a chore swapping them in. Don't plan on doing this routinely. Buy several units cheaply (~$100 on eBay) as needed. Indeed, as described above, these are the standard 18 dB cards loaded with components specific to 4430/35. Card designations "peek" through the front panel.

While in there, dip switches (one of two visible here, red) set LP filter parameters, including options for various (but limited) slopes and frequencies. While "flat" is available, I chose a Q=2 6 dB "bump" at 20 Hz to mimic BX63(A)'s "assist" for B380. I know, I know, it's dangerous to boost low frequency below the box tuning point, which may induce over-excursion of the driver, but I promise to keep the gain modest until capacitors come in to shift this up to the recommended 26 Hz. Do NOT try this when biamping a stock 4430, which is tuned even higher!

On to "critical listening," then.... :D

4313B
02-16-2005, 02:30 PM
I know, I knowOk then...

Zilch
02-16-2005, 02:38 PM
It's fun to take risks!

Replacement 2235's are on the way, just in case... :D

[How risky IS this, in reality?]

4313B
02-16-2005, 02:45 PM
[How risky IS this, in reality?]It isn't risky for people who monitor their systems and take care of them. For people with a propensity to get drunk/stoned/medicated and then operate heavy machinery it could be an issue. :p

Zilch
02-16-2005, 04:36 PM
"Full Monty" JBL system, then, assembled with the assistance of forum members, comprises:

1) TimG's 2427H drivers on Mike Caldwell's 2344A horns,
2) Thrashed B380's I had in the dungeon, acquired cheaply, 2235H's refoamed,
3) N3134 factory 4430 passive crossovers bought on whim 10 years ago "just in case," when they were about 1/3 the current $565 cost (hopin' Giskard's gonna show us how to make 'em DIY, maybe),
4) JBL 6260 amp driving the B380's, bought off eBay (now ~$150),
5) JBL 6230 amp driving the horns, bought on local pro dealer "clearance," also 10 years ago (now ~$125 on eBay),
6) JBL 5235 active crossover recently bought off eBay, same vintage as amps (~$100),
7) 4430 crossover cards on loan from RobH,
8) $79 Sony CDP-XE400 CD player with "High Density Linear Converter,"
9) DOD Real-Time Analyzer on loan from Mr. Widget,
10) HOSA XLR cables from Guitar Center pro audio department (~$60),
11) Cheap Radio Shack hookup wire, available even cheaper at Home Depot(~$7), and,
12) Various and sundry Pink Floyd (priceless).

Quick AND dirty, with considerable assistance from this forum, the test platform is complete. :applaud:

Bring on them HORNS, JBL!

[Gonna go listen now....]

Mr. Widget
02-16-2005, 04:53 PM
Looks like a bit of EQ could be used to reduce the peaks ~50-63Hz and ~1-1.2KHz and bring up the highs and lows.

Widget

Zilch
02-16-2005, 05:07 PM
Hi, Mr. Widget!

I was hopin' you'd come on to interpret the RTA. Not bad for "outta the box," I think.

The low end was probably fixed by movin' the bump filter down to 20 Hz in a moment of wanton bravado earlier today. It was set on 30 Hz for safety last night, and it pushed up the 63 Hz region. I'll measure it again tonight. Gotta be after dark to get that pic.

I reversed the phase on the horns to get that peak at 1K crossover point, where it was dipping a bit. Maybe I just move them back and forth a little instead.

The RTA is REAL sensitive: approach the mic and the curve changes. The two peaks shown there are really just blinkin' on and off, whereas the rest of it is all steady on.

That flat setting is kinda "harsh" for my taste, but it may just be the hardness of the room (garage) makin' me want to back off the midrange somewhat here.

For those unfamiliar, each row of LED's there is 3 dB. I'm a noob with RTA, and just learning how to interpret it myself.... :p

What's shown is it's dialable basically flat (within 3 dB) from 40 to 12.5 kHz in this decidedly less than ideal environment without any EQ other than the crossovers themselves. Note there's no preamp or EQ (which I don't have, anyway,) in the system. It's all just direct connected.

Robh3606
02-16-2005, 05:50 PM
Try moving the horn up a bit. The real deal has the horn out an inch in front of the baffle.

Rob:)

johnaec
02-16-2005, 06:06 PM
Also, don't forget to take Fletcher-Munson equal loudness curves into account. I find I always have to compensate for those unless the volume is near to "live band" levels. At low volumes, "flat" can sound real dead...


John

Zilch
02-16-2005, 11:38 PM
Try moving the horn up a bit. The real deal has the horn out an inch in front of the baffle.Yup, I was lookin' for a pair of 2507 horn brackets so I could hang them over the front edge, but none's come out of the woodwork here yet. May have to make something up myself to accomplish that enhancement.


Also, don't forget to take Fletcher-Munson equal loudness curves into account.Yup. Letting the mids lag sounds better. Gotta get a cheap Radio Shack SPL meter tomorrow to find out where I'm actually running absolute, probably. No volume or loudness control on this setup; I have to adjust 4 gain controls to vary it, so we're basically one level here. It'd be good to know what that actually is.... :D

caladois
02-17-2005, 10:01 AM
6) JBL 5235 active crossover recently bought off eBay, same vintage as amps (~$100),
7) 4430 crossover cards on loan from RobH,
Bring on them HORNS, JBL!


I am looking too for 4435/4430 crossovers cards ? are they still available ?
What price ?

Regards SD]

Zilch
02-17-2005, 11:35 AM
I am looking too for 4435/4430 crossovers cards ? are they still available ?When last I checked with JBL parts (about a year ago), they were NLA (No Longer Available).

"No, none, and NEVER again. Forget it."

[That doesn't mean they don't have them though.... :D ]

HOWEVER, as documented above, they are easy to replicate. The components required for the various filters and frequencies are specified in the 5235 manual.

The cards came in two forms, 12 dB and 18 dB, with different circuit layouts. If your crossover came with 18 dB cards (6 capacitors and 6 resistors) of ANY frequency, they can be reloaded with the requisite components for the 4430/35 configuration.

Alternatively, you can easily make (or have made) them yourself, using the stock cards as models. They almost never show up on US eBay, so plan on using your own resources to make it happen.

Zilch
02-17-2005, 05:59 PM
1) For low frequency equalization, S3 is opened.
2) Closing S2 provides 30 Hz Q=2 Bump.
3) Additionally closing S1 doubles C10 making it 20 Hz.
4) For 26 Hz, add 40% of C9 instead, i.e. 0.4 x 0.27 uf = 0.108 uf.
5) Leaving S1 open and adding 0.108 uf across C10 will make 26 Hz.

Check?

26 Hz is what we want to emulate BX63 for B380, yes?

4313B
02-17-2005, 06:04 PM
Sounds right. Did you find my post how to do this?

No wait. That sounds wrong ( doesn't mean it is though :p ).
Let me search the forum.

Here -

http://audioheritage.csdco.com/vbulletin/showthread.php?t=610&highlight=5234A+B380

I don't have time to read through it right now. I'll run your proposal later in pspice.

Zilch
02-17-2005, 06:11 PM
Had to look again at the schematic pdf. The caps are 0.27, not .027. I fixed that above.

Hmmmm. Replacing ALL of the caps seems excessive. Just kludging one on in parallel is more easily reversible, if it'll work.

0.11 or 0.12 uf proposed....

4313B
02-18-2005, 02:02 AM
Hmmmm. Replacing ALL of the caps seems excessive. Just kludging one on in parallel is more easily reversible, if it'll work.

0.11 or 0.12 uf proposed....Replacing ALL of the caps was done to match the switch positions and shift everything.

A 0.1 uF across C10 is fine and the dips will be 0100. :)

Zilch
02-18-2005, 01:03 PM
Found 0.11 uf metalized polypropylene cap, 63 Volt, for 45 (10) at Digikey (page 5, here: http://dkc3.digikey.com/PDF/T051/0946-0952.pdf) #BC2055-ND. Ordered.

Potentially also an easy mod of JBL 5235 for use as subwoofer crossover with 26 Hz Q=2 (6 dB) bump for B380/B460 per BX63(A). Choose filter card components from list provided in 5235 manual here: http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/JBL-5235%20manual.pdf. JBL standard sub card for 5235 is 80 Hz, 18 dB.

Again, DON'T use this mod if you're biamping stock 4430's with 5235. The standard box tuning is wrong for this, (too high) and you'll risk damage to your woofers.

Not until we develop a considered scheme for retuning them, at least.... :D

4313B
02-18-2005, 01:16 PM
Again, DON'T use this mod if you're biamping stock 4430's with 5235. The standard box tuning is wrong for this, (too high) and you'll risk damage to your woofers.Block one of the stock 4430 ports and it will be fine. That drops the tuning down to around 25 - 26 Hz.

Zilch
02-18-2005, 01:19 PM
Heh, heh. Requisite consideration provided. :p

[Off to the plumbing store again for more proprietary port blocking devices, then....]

Zilch
02-18-2005, 07:28 PM
With assistance of rat-tail file, diminutive 3" diaphragm 2431H neodymium-magnet drivers fit onto 1-1/2" P-Audio horns. They sound brighter to me than LE85, 2426 or 2427. RTA says it's not because of any HF extension, rather, a little less SPL around 1 kHz, the crossover frequency. The assembly is shorter than any other so far, so it may just be the same phasing issue encountered above.

Are they cleaner or smoother than the other drivers as alleged? Could YOU tell playin' Pink Floyd? Wish we had some specs on these things. :(

[I think they ARE, actually....]

Horn gasket on face of drivers looks like Silpad, a thermally conductive silicone pad material, commonly used to couple power transistors to heat sinks, which would conduct heat to aluminum horns, if used. Very clever, if so....

Zilch
02-18-2005, 07:35 PM
Up from the dungeon, near-mint pair of L200 cabs beg for reincarnation as 4430's. Hold on just a little bit longer, nice cabs. It LOOKS like we're gettin' there. :)

[Giskard already sent you some lovely new woofers....]

Again, we need those HORNS, JBL!

Mr. Widget
02-18-2005, 07:45 PM
You are not really going to put butt cheeks into those beautiful cabinets! :barf:


Widget

Zilch
02-18-2005, 07:46 PM
Heh, heh, they'll JUST fit....

AND they'll hide behind the grilles. :p

Word is YOU have a pair of L200's what could use some rework, too, Mr. Widget! :applaud:

[Don't anybody start cuttin' into their L200's, now! Mr. Widget is NOT done yet....]

Mr. Widget
02-18-2005, 07:51 PM
No I don't, but I'd buy yours if it would stop you from sticking those foul things out the front of those beautiful walnut cabinets. I thought you had some junkers that were being salvaged from Urban Ore.


Widget

Zilch
02-18-2005, 07:55 PM
I thought you had some junkers that were being salvaged from Urban Ore.I'll sell you the LX-16 crossovers REAL cheap, but folks have taken a liking to LE15B's on eBay of late.

[Can't imagine why, tho....]

Mr. Widget
02-18-2005, 08:10 PM
Now why would I want a pair of LX16s?

I just think that trashing a near mint L200 is like adding a wing to the back of a '65 Mustang.

Widget

Zilch
02-18-2005, 08:20 PM
They've always been crap. JBL tried to fix 'em and failed. The only rational solution is to make them into ... [I can hardly type the words, now, ... ack ... ACK, I'm gaggin' here ...] THREE-WAYS! :biting:

[We gonna do WAY better'n that.... :p ]

Ian Mackenzie
02-18-2005, 08:44 PM
None of my business but my preferred alternative would be a 2123H in matching timber sub enclosure sitting atop the exisiting cabinet. Hence a 4 way thay will wipe the floor with those bum horns.

Ian

Mr. Widget
02-18-2005, 08:46 PM
Widget

Zilch
02-18-2005, 09:47 PM
BWAHAHAHAH!

:rockon1: :bouncy:

Mr. Widget
02-18-2005, 10:22 PM
That's OK Zilch. Your secret is safe with me. :applaud:

Widget

Zilch
02-19-2005, 12:02 PM
You are not really going to put butt cheeks into those beautiful cabinets! JBL did some earlier work attempting to resolve the aesthetics issue. In Asia, they were considered downright offensive, apparently.

http://audioheritage.org/vbulletin/showthread.php?t=2477&highlight=4425+MK2

There are other flat-front Biradial horns, of course, but none with the wide 100 x 100 pattern of the 2344(A) used in 4430. I tried 2370A first in this project, and have used it successfully before in others, but its limited (40) vertical dispersion is just too much of a compromise for this one.

That's (in part) why the new PT horns are of particular interest here. While the square one (12" x 12") won't fit into L200 any better than 2344(A) (it gets pushed right up under the top overhang, and cannot maintain the 4430's center to center spacing), the rectangular one looks like it would fit nicely while retaining the 4430's 100 x 100 distribution. The aesthetics are not an issue, really. Even the 2344A will fit behind the L200's grille, though probably not with 4430's additional 1" time-alignment compensation.

According to the technical note, the rectangular PT horn has lower distortion, but not quite as good pattern control. I don't think we care about the patten so much, as long as it approaches 4430 performance. It'd be a major plus if it could be successfully mated with L200 and L200B's 16-Ohm LE85, which we have already determined is a worthy contender in this upgrade.

The problem, of course, is the crossover. L200's LX16 seems a total loss, but, as we have shown, there may yet be hope for modified N200B. Whether the new horns will play down to 800 Hz is also a major issue. We may end up reworking N3134 for 16-Ohms as an option. It's largely contingent on how the PT "waveguides" measure out.

http://www.jblpro.com/ae/pdf/PT_WaveGuide.pdf

Note: The P-Audio horn isn't entirely out of the running. It sounds mighty nice with 2431H running it. Also, Mr. Widget hasn't yet had opportunity to do critical listening to the OASR horns. Me neither....

Guido
02-19-2005, 12:20 PM
Again, we need those HORNS, JBL!

They store those horns in a safe with electronic time lock and every morning only the ones needed for AE production are given out :D

I couldn't understand this behavior when I tried to get them and I do not understand it now.

I really hope they will become available.

Mr. Widget
02-19-2005, 12:30 PM
"Even the 2344A will fit behind the L200's grille, though probably not with 4430's additional 1" time-alignment compensation."

Look at your sloped L200 baffle. I think you will need substantially greater than 1" to get them back into alignment.

How about I build you a nice set of 4430 boxes in exchange for those L200 cabinets?

Widget

Zilch
02-19-2005, 12:38 PM
How about I build you a nice set of 4430 boxes in exchange for those L200 cabinets?And what would YOU put in these exceptional, rare, and uniquely well-preserved L200 cabs, Mr. Widget? ;)

[Heh, heh....]

Mr. Widget
02-19-2005, 01:56 PM
I would put a 2235 in the big hole, fabricate a reversible mount to put an 077 or 076 in the small hole and put one of these on top of the cabinet. :)

Widget

Zilch
02-19-2005, 02:08 PM
[Wonders if 2427H with stock 2" throat adapter from TimG will play on them black TAD horns Mr. Widget's been wantin' to dispose of over there....] :D

Alex Lancaster
02-19-2005, 02:25 PM
:) IMO, I agree with Widget, L200s are "vintage", my brother and I have 4 really mint, not eBay mint, and I added 4 external tweeters, 4 S120PII subs, and it really rocks on the boardroom at his office, otherwise known as the drunkodrome, We even have a big pottery piggy bank for contributions toward a big screen, We already have a medium duty icemaker; The point is, pls leave the oldies alone.

Ian Mackenzie
02-19-2005, 03:50 PM
:) IMO, I agree with Widget, L200s are "vintage", my brother and I have 4 really mint, not eBay mint, and I added 4 external tweeters, 4 S120PII subs, and it really rocks on the boardroom at his office, otherwise known as the drunkodrome, We even have a big pottery piggy bank for contributions toward a big screen, We already have a medium duty icemaker; The point is, pls leave the oldies alone.

I can see what Zilch is about but I tend to agree with Alex.

Perhaps all this great R & D could be used for a nice current day JBL of your own design.

Ian

Zilch
02-20-2005, 10:24 AM
Perhaps all this great R & D could be used for a nice current day JBL of your own design.There's no denying we're learnin' stuff here, and havin' plenty good fun too!

I'm thinkin' something scaled down a bit, with LE14H-1 as the LF driver. Put some of them LE14A's out there (and in here, as well) back into service, maybe.

[Wonders how high LE14H-3 will play?]

That's another thread, tho, once we get there.... :D

4313B
02-20-2005, 10:42 AM
I've seriously considered pairing the LE14H-1's with my 4430 top ends but the efficiency hit pains me. :p

It looks really nice though... I might have to give it a go anyway...


Perhaps all this great R & D could be used for a nice current day JBL of your own design.You sound like some folks at JBL. :p

There's no denying we're learnin' stuff here, and havin' plenty good fun too!Yeah, I'll refrain from raining on the parade. :)

Zilch
02-20-2005, 12:07 PM
I've seriously considered pairing the LE14H-1's with my 4430 top ends but the efficiency hit pains me.Amps'r cheap.

'Course there's ALWAYS the possibliity of doublin' up for quasi-4435. :bouncy:


Yeah, I'll refrain from raining on the parade.Heh. We've got some surprises yet comin', I betcha.... :p

Zilch
02-20-2005, 02:36 PM
2431H phase plug structure is different, no? Hard to photograph through the screen, there appears to be a 3/8" bore down the center. Illuminated with a flashlight, I THINK I can see straight through to the diaphragm. Nope, I'm NOT gonna disassemble for a more definitive look.

After a day's breakin, I found them playing even brighter than initially, and had to back down the HF boost about 4 dB on N3134. Further investigation with RTA revealed a symmetrical 6 dB peak at 8 kHz, shown below (crossover levels set at 0 db). With proper EQ, 2431H could potentially sweeten 4430 by pushing response to 20 kHz or beyond, so long as distortion doesn't take over. Rightmost column is 20 kHz, next is 16 kHz.

[Note: 2431H is a 1.5" driver and does not fit directly on 1" 2344A horn.]

2431H seemingly does not collapse at HF like the other drivers we've tried here, at least not at quite so low a frequency. More details after better and more comprehensive testing. Independent confirmation always appreciated (I've been fooled before).

Guido: If you don't have 2431H's yet, get them and mount on your P-Audio horns. Your rep may have been correct in suggesting that N3134/5 does not have the optimum EQ, but I think you'll be pleased in any case. (Don't forget to turn the horns 90, tho.... :p)

Zilch
02-21-2005, 10:55 PM
This project's most pleasant surprise thus far, I didn't believe OASR horns would deserve a separate system designation until I gave them a good listen with EQ. At a paltry $76 a pair, these are credible performers.

At standard biamped 4430 crossover EQ, they run head to head with 2344A on 2427H drivers. They're more up front (less transparent) than the biradials, and lack their wide field constant directivity (see earlier tests by Mr. Widget here), but they sound mightily good. They remind me of Meyer Sound horns, actually.

Mount directly to threaded snoot of 2426 or 2427, or use throat adapter on three-bolt 1" drivers such as 2425 and LE85. I used P-Audio PC-35 ($10) for testing on LE85, available here:

http://www.loudspeakersplus.com/html/paudioadapters.html

Note: $49.99 (9-Volt battery NOT included) Radio Shack dB meter (C scale) says I'm running 80 dB typical SPL in listening tests here. That's pretty safe, allegedly, but it's certainly worth knowing. Zilchster recommended hearing preservation equipment; includes instructions for plotting and adjusting system frequency response the hard way using test tone disc (by others).... :)

Ian Mackenzie
02-22-2005, 04:22 AM
I met someone up in the Sierra's who used a Behringer UltraCurve to create the desired EQ for a Tad 2001 on the 2344 I sold him.

He then tweaked the stock JBL 3134 values until the passive EQ matched the Ultra Curve EQ'd reponse.

That was the smartest bit of crossover design I saw in my travels across the USA. The guy was Kent English c /- Passlabs.

I may even buy an UltraCurve myself , they quite reasonably priced.

Ian


Ps I recall him saying the Tad need less upper lift

Zilch
02-22-2005, 10:14 AM
This guy?

http://www.behringer.com/DEQ2496/index.cfm?lang=ENG

I recall an earlier discussion here about these units. At $360, it's time for me to get serious about looking, probably. Gonna need my own RTA, and it's built in, apparently.

Also, maybe their crossover ($300):

http://www.behringer.com/DCX2496/index.cfm?lang=ENG

Read the manuals and search the forum, Zilchster.... :)

Robh3606
02-22-2005, 10:28 AM
I use a Behringer 8024 for my RTA. Got it cheap! Works great! That DCX 2496 certainly is inexpensive. Lot's of flexibility with the PC interface. Makes it easier to use than the just the screen.


Rob:)

mikebake
02-22-2005, 10:29 AM
I've got an Ultracurve; bought it new, never used it but once. I oughtta hook it up and use it a bit..........I figured that in another year or so I'd look at the current offerings in DSP/EQ/RTA/controllers and see whats shakin'. Haven't quite seen what I want yet, that is affordable for me.

Zilch
02-22-2005, 10:50 AM
I ain't buyin' no laptop t' use in the garage. Nope, nope.

O.K., well, MAYBE not, then....

That gear is sure ugly.

Behringer could certainly benefit from consultation with the Lansing Heritage Forum industrial design team! :p

Mr. Widget
02-22-2005, 11:01 AM
Zilch,

I haven't paid much attention to the Behringer stuff, but I know that Infredible bought one model of Behringer RTA/EQ and hated it and replaced it with a different model from them and was much happier with it.

Widget

Ian Mackenzie
02-22-2005, 11:14 AM
This guy?

http://www.behringer.com/DEQ2496/index.cfm?lang=ENG

I recall an earlier discussion here about these units. At $360, it's time for me to get serious about looking, probably. Gonna need my own RTA, and it's built in, apparently.

Also, maybe their crossover ($300):

http://www.behringer.com/DCX2496/index.cfm?lang=ENG

Read the manuals and search the forum, Zilchster.... :)

I've known Kent for a while, he's basically a full time R & D man up there and spent two years measuring and listening to just about every speaker he could find when designing the Rushmore. He also has a great crossover switch box that he spotted at the CES for a couple of hundred bucks.

You can just see the Behinger on the shelf and his trusty Crown RTA.
You ain't ever heard Altec horns (driven by Tads) sound so good.

Mind you I had just visited The Widget and had the luxury of nursing Bo's 4345's for a few days so I was totally bonkas over anything to do with audio, Californian woman and red wine at this stage.

I'm planning on looking at the UltraCurve today.

Ian

Zilch
02-22-2005, 11:49 AM
Yeah, I'll refrain from raining on the parade. :)It's more and more lookin' like a PILGRIMAGE, actually.... ;)

Widget: Where IS that Freddie, anyways? Somebody needs to go rattle his cage, maybe. :)

Zilchster wantsa ride in his "Z," as the venerable Zilchmobile is in its final days here, alas....

Ian: PM me Kent's contact info, if it wouldn't be an intrusion, please. Maybe I give him a little call or eMail for advice and recommendations. Perhaps I can encourage him to post it here for everyone....

Robh3606
02-22-2005, 12:29 PM
"I'm planning on looking and UltraCurve today."

Don't get the 8024 go for the 2496. Better with more flexabillity and you can adjust the input sensitivity so you can run at home and not Pro levels. I have an 8024 which is what Kent's looks like. Never used it as an EQ have the analog Urie 839's for that.

Rob:)


http://www.behringer.com/DSP8024/index.cfm?lang=ENG

Ian Mackenzie
02-22-2005, 01:08 PM
It's more and more lookin' like a PILGRIMAGE, actually.... ;)

Widget: Where IS that Freddie, anyways? Somebody needs to go rattle his cage, maybe. :)

Zilchster wantsa ride in his "Z," as the venerable Zilchmobile is in its final days here, alas....

Ian: PM me Kent's contact info, if it wouldn't be an intrusion, please. Maybe I give him a little call or eMail for advice and recommendations. Perhaps I can encourage him to post it here for everyone....

Okay,

Someone elses ears already pricked up about this so your second in line.

Kent is a super cool guy and just loves his diy stuff.

Ian

Guido
02-22-2005, 03:41 PM
Guido: If you don't have 2431H's yet, get them and mount on your P-Audio horns. Your rep may have been correct in suggesting that N3134/5 does not have the optimum EQ, but I think you'll be pleased in any case. (Don't forget to turn the horns 90, tho.... :p)

Zilch, could you please PM me what you have paid for the 2431H?

What is the current plea from JBL for not sending the Waveguides?

Infredible
02-22-2005, 04:04 PM
Yeah! forget about the 8024, mine seats on the storage shelf now. Bad DACs I suppose, lots of jitter in the background. I brought the 2496 and now I'm really happy with the sound and It's a much better machine to use. I got it localy for $376. As for the Z that is another story :D

Fred.


"I'm planning on looking and UltraCurve today."

Don't get the 8024 go for the 2496. Better with more flexabillity and you can adjust the input sensitivity so you can run at home and not Pro levels. I have an 8024 which is what Kent's looks like. Never used it as an EQ have the analog Urie 839's for that.

Rob:)


http://www.behringer.com/DSP8024/index.cfm?lang=ENG

stephane RAME
02-22-2005, 10:35 PM
for 2 way or 3 way + EQ + RTA

stephane RAME
02-22-2005, 10:39 PM
http://www.driverack.com/PA.htm

Zilch
02-23-2005, 12:05 AM
Alas, no prices there I could find. What kinda $$$ are involved?

Ian Mackenzie
02-23-2005, 03:39 AM
I had a look at some of this stuff today and plan to do more research with some people who use the gear in the field.

Initially I was thinking of using the Ultra curve as a developement tool but note it can be operated as digital in/out device which if used with a CD source having an up sampled digital output of say 24/96 could have possibilities partnered with a nice D/A converter at the post EQ end of the digital chain.

Ian

stephane RAME
02-23-2005, 04:15 AM
behringer

Zilch
02-23-2005, 09:35 AM
So, that's a "Yes" on 2496 from Ian, I think, and two of the three members who have 8024's say get 2496 instead, looks like.

The DriveRack has JBL endorsement and support, no?

Again, apart from their utility as RTA and EQ, the concept for crossover development is to use them to determine the desired compensation and replicate that in a passive design. I presume, optimally, that means having access to the actual amount of compensation provided in each band with somewhat better precision than +/- 1 dB?

Or is this a process of successive approximation, i.e., build it, try it, and tweak some more? I mean, there's no "integrated" approach to this with uploads of empirical EQ determinations to crossover design simulation software?

I'm kinda likin' Keith Kidder's Box of Doom (http://mywebpages.comcast.net/kidder/Audio/BoD/BoD.htm) concept, too! It don't do pole sliding or splitting, or phase delay and time alignment compensation, but you DO get practice winding tapped inductors. :p

Ian Mackenzie
02-23-2005, 11:23 AM
Sorry, I meant upsampled using an upsample converter to 24 bit/ 96 khz out of the CD player then feed in to an Ultra Curve for kinda like pre conditioning the signal while in virgin digital format, then convert to analaogue with a D/A converter.

I think taking an analogue signal already converted from digital to analogue then convert to digital and back to analogue is not going to help the signal purity.

Upsampling tends to improve post production quality, the problem being the output of most CD players playing normal CD is 16 bit.

Anyway, I only bought this up as the UltraVCurve appears a cool way to create the EQ for constant CD horns which are all a little and I think this is why some CD horns get a back wrap as they are seldom flat enough for hifi playback using stock crossover EQ compensation. The voltage drive from the UltrCurve can then be used to build a suitable passive network or if you like digital processing just keep the UltraCurve in the signal path. I have not used the 2496 speaker processor but based on others experiences care needs to be taken to ensure audiophile grae sound quality.

I heard a DBX drive rack at Jarrods recently, the speakers are certainly in the ball park but I am not sure about the processor. We plan to compare my prototype hi end analogue crossover soon.

Ian

Zilch
02-23-2005, 11:37 AM
The voltage drive from the UltrCurve can then be used to build a suitable passive network.... That's the part I'm not getting yet. Can you read the actual compensation in each band from some menu there, or would you have to feed it known magnitude tones and measure the output to determine the voltage drive curve?

Robh3606
02-23-2005, 12:07 PM
All you have to do is run the horn/compression driver combo with no comp and let the Ultra Curve run it's automatic room EQ mode. That will get you very close to where you need to be. The bands on the EQ give you the curve for the voltage drive.

Rob:)

Zilch
02-23-2005, 12:18 PM
Thanks, Rob!

Do you then have to guestimate the curve by reading it from the graphic screen, or are the actual compensation values available elsewhere for each band, i.e., like from a cursor you move from band to band to read them?

Robh3606
02-23-2005, 12:30 PM
You can read the levels in each band directly and go from there. Just save it in a memory and do what you want with it. It's an aproximation but it will at least give you the shape and some idea on the changes band to band.

Rob:)

Zilch
02-23-2005, 12:53 PM
O.K., two choices, then:

Read the uncompensated performance from the RTA, or,
Let it compensate and read the resultant curve from the EQ.
Somehow, I think "Go from there" is gonna be the hard part. :p

Robh3606
02-23-2005, 02:23 PM
Somehow, I think "Go from there" is gonna be the hard part. :p

If it was only that easy! ;)

Rob:)

Zilch
02-24-2005, 05:27 PM
Similar to 2344A, 12" square 100 x 100 PT waveguide incorporates engineered throat constriction, shown in front and rear views, below. I haven't again come across the Tech Note that says why yet, but it matters.

JBL logo and beamwidth specifications are embossed on the face.

While the depth of the horns are nearly identical, the complete assembly with 2431H mounted is significantly less than original 2425H on 2344 left, below. Clearly, the time alignment will be different. I don't know where to measure how much, though. The front plates?

[Me go listen now....] :D

Preliminary report: These things work plenty good....

Zilch
02-24-2005, 05:32 PM
2431H on 12" square PT waveguides, N3134 crossovers, biamped.

Guido's rep was apparently right. While this combination can be tuned flat with the 4430 crossover, it is not optimum. It's apparently matched to the larger 4" diaphragm 242x drivers, whereas, 3" 2431 is different. More HF extension would be available with 2431H if N3134 didn't boost so much at 8 kHz, as earlier demonstrated with this driver. Boost the HF and I lose balance with the upper mids at 2 KHz. Maybe I move the HF boost frequency up by reducing N3134's C9 a bit?

http://www.jblproservice.com/pdf/Network%20Schematics/3134%20Network.pdf

Time to get serious about programmable EQ, apparently, to see what these babies can actually DO. :D

[Mr. Widget's measurements will tell the tale....]

TimG
02-24-2005, 06:31 PM
I received my JBL 1" to 1.5" throat adapters and they have a similar curve incorporated into them. The throat appears to narrow to about .875" before expanding to 1.5". I planned on bolting these to my SRX horns, but the bolts enter from the inside of the SRX horn and they don't line up with any holes on the adapters unless I rotate them to an odd angle. I will post pictures next week. The adapters have four holes and 2 pins that look like they would line up with the holes on your 1010 horns.

The K2 S9800 horns have a similar pinched throat. On that horn the narrowest section is oriented horizontally.

Zilch
02-24-2005, 07:18 PM
Thanks, Tim.

I ordered up the adapters also. I don't know what the pins are about, but we'll see. Please post your findings here. Those adapters allegedly mate with the rectangular 1010 waveguides, as well. If so, we'll test your 2427H's and LE85's (double-adapted) with both PT horn configurations.

The P-Audio adapters you worked with are also easily modified to different bolt circles, but I'd like to see what's up with the JBL ones first, as there are no constrictions in them, just a smooth transition. I'm thinking that since the adapter negates the constriction in the 1-1/2" horn, it must be reinstated at the 1" driver.

Apparently, there are orientation issues with the 2431H driver as well. I mounted one 90 rotated inadvertently, and the performance was different. Even the square horn is termed "rotatable," so there are preferences. Perhaps the pins make sure the throats are joined in the optimum relationship for the constrictions to operate as designed.

Guido
02-25-2005, 03:27 AM
I received my JBL 1" to 1.5" throat adapters and they have a similar curve incorporated into them. The throat appears to narrow to about .875" before expanding to 1.5".

Tim,
does this mean that if I use this adaptor on the PT Waveguide I will have 2 times this curve?
Once in the Adaptor and once inside the horn? Or did I get something wrong?
Are you talking about the 339308-001 adapter that fits the 2418 driver to the PT Waveguide in the AC2215?

Guido
02-25-2005, 03:29 AM
Zilch!

Congratulations! You got them! Can't believe it. We have to figure out a passive network for the 2431/Waveguide combo. I prefer passives. BTW I posted a pic of my 4425 filters here:
http://audioheritage.csdco.com/vbulletin/showthread.php?t=4876

Zilch
02-25-2005, 10:18 AM
We have to figure out a passive network for the 2431/Waveguide combo. I prefer passives.Yup. I'm starting with the AM6212/00 factory crossovers you cited earlier. These are a decidedly different species; we'll be taking meaurements to determine what is required as soon as the other (rectangular) version arrives.

Just as well, perhaps. N3134 is a big stumbling block to an L200 upgrade. As always, I'm looking for something simple. With a little more investigation, we may find that N200B is applicable here, for those who have them. For L200/B upgrades, I'm aiming to reuse the LE85's that come with, but for a "sweetened" 4430, the 2431H seems quite promising at this point. Even with the wrong crossover, they sound good!

The waveguide alone may be an improvement to 4430. It's certainly a more reasonably priced option for DIY, and with the throat adapter, may accommodate 2426/7. An even cheaper choice would be 2418H-1, as used in AC2215/00, though that's gettin' more like 4425, probably. We'll see....

Zilch
02-25-2005, 07:35 PM
0.11 uf Metallized Polypropylene (MKP) capacitors are kludged across C10 and C110 on solder side of 5235 crossover mother board to lower 30 Hz Q=2 bump filter to B380 26 Hz tuning per BX63(A) spec. Mod also lowers 20 Hz filter to 18 Hz if dipswitch S1 is enabled as well as S2, the new 26 Hz setting (heh, heh....) Factory had a little kludge of their own there to replace a missing trace on this particular board.

Did it work? Well, it's not apparent on the RTA display capture shown below, but Pink Floyd says "YES!" :D

Note significant 2431H HF extension to 20 kHz and likely beyond on the RTA display. These ARE improved drivers, at least when used on PT waveguides.

L200's, one port in each blocked with plumbing test plugs for 26 Hz box tuning, await arrival of Giskard's 2235's. At approximately 5.25 cu.ft., they dwarf wimpy-weenie B380's. For standard 4430 tuning, merely remove these proprietary precision port tuning devices. :p

Does this begin to make sense yet?

Robh3606
02-25-2005, 08:02 PM
What's the resolution on the RTA?? How many dB per LED?? What's the throat size on the 2431's??

Rob:)

Zilch
02-25-2005, 08:26 PM
RTA resolution is switch selectable for 1 dB or 3 dB per row. That's a 3 dB capture. 1 dB is, ummmm, "messy." ;)

Still using N3134 crossover with them.

2431H is 1.5 inch throat, bolt-on....

Robh3606
02-25-2005, 08:28 PM
So you would go direct on the new horns?? Were they expensive??

Rob:)

Zilch
02-25-2005, 08:31 PM
List for 2431HPL is $399, and the horns are $84, both from Pro Parts.

Yeah, they're direct bolt-on. See pics on previous page.

Owing to neodymium magnet and less bulk in the horn, the entire assembly is very light, maybe 1/3 the weight of 2426/2344A. It could possibly self-support....

Robh3606
02-25-2005, 09:00 PM
Thanks those horns are very reasonable, the drivers are not that bad either. Are they aluminum, aquaplas dusted aluminum?

Rob:)

Zilch
02-25-2005, 10:22 PM
I believe they are aluminum, which by many accounts sounds smoother than titanium. There may be other design enhancements, but I'm not about to open this pair up to "discover" them just yet. ;)

There's no published spec sheet that I've been able to find, either, just their specs in a few current systems. We'll measure them to determine their actual performance, once the other waveguides come in. All I have to go by so far is what I hear and what I see on the RTA in comparison to known drivers we've studied here.

They need different EQ than 2426H, for example, and they exhibit extended HF in comparison. They sound very good on the PT waveguides, and they're not bad on the P-Audio horns, either, as I suggested to Guido earlier.

They've been manufactured for about a year now, I think, maybe longer. My two units are "vintage;" final test dates 2/20/04 and 5/26/04. :p

Zilch
02-26-2005, 11:08 AM
Zilch!

We have to figure out a passive network for the 2431/Waveguide combo. I prefer passive networks. All of the action is in the HF section of the 4430 passive crossover, it seems, which stays in play when biamping. It'd be good if the same approach were continued so they could be used either way. The HF portion of 5235 is a simple single pole.

The LF section of N3134 is easily replicated and maintained, either passive or active, except L102, perhaps. I don't know why the LF of AM6212/00 is so "busy." Looks like a couple of notches to tame 2206H, which we don't need. Nobody's highlighted any special role of 5235 EQ card LF filter that I've seen. I'd like to keep 5235's separate 26 Hz bump filter when biamping, tho, obviously. ;)

I am confident others here will help us, once we determine what is actually required. :)

4313B
02-26-2005, 11:32 AM
This seems to be a good time to post some old notes -

The 2431 is an improved 2430 and offers better high frequency response. It has an improved surround. The 435AL is the consumer version of the 2431. They all use aluminum diaphragms with improved kapton surrounds.

The 2425/2426 is fairly breakup free up to around 15 kHz. It starts to roll off around 2 kHz and is easy to passively EQ. The aluminum diaphragm offers better damping while the titanium diaphragm offers greater reliability.

The 435BE is the consumer version of the 2435 and has a larger back can to lower the useable response from around 1 kHz to around 650 Hz. It is quite happy down to 800 Hz. Slope roll-off is curved such that passive EQ is difficult. Roll-off starts around 7 kHz. Digital parametric EQ is the way to go. Watch out for latency in digital crossovers.

The 045 drivers are compression drivers with very small apatures, 0.35", that allow for excellent HF dispersion. They are flat to 50 kHz whereas the ring radiators drop like a rock around 15 to 20 kHz. The ring radiators are extremely efficient at the expense of ultra flat wide bandwidth response.


There's no published spec sheet that I've been able to find, either, just their specs in a few current systems. We'll measure them to determine their actual performance, once the other waveguides come in. All I have to go by so far is what I hear and what I see on the RTA in comparison to known drivers we've studied here.Yes, the burden of measuring these various drivers rests with you.


The LF section of N3134 is easily replicated and maintained, either passive or active, except L102, perhaps.Indeed it is. L102 is a 0.6 ohm DCR inductor - easy enough to aquire.

Mr. Widget
02-26-2005, 11:40 AM
The 435AL is the consumer version of the 2431.

The 435BE is the consumer version of the 2435 and has a larger back can to lower the useable response from around 1 kHz to around 650 Hz.

The 045 drivers are compression drivers with very small apatures, 0.35", that allow for excellent HF dispersion.


Hey Giskard,

I have a couple of questions/clarifications. If you haven't already discussed these with the powers that be maybe you could inquire.

Doesn't the 435AL also have the larger back cap like the 435Be but the 2431 does not?

Aren't there also differences between the 435Be and 2435 in the amount of aquaplass dusted on the diaphragm and/or ferro fluid added?

What are the performance differences between the 045Be and 045AL? The cost difference is significant.

Widget

Zilch
02-26-2005, 11:49 AM
Thank you, Giskard!

The Be verisons are HELLA expensive, alas, but what you say about 2431H is all good, except, perhaps, for the "difficult to do passive EQ" part.

I'm surprised 2431H hasn't gotten more play from my experience with it so far.

[Hmmmm. Wonders what 435AL is used in? Maybe there's some clues there....]

Guido
02-26-2005, 11:54 AM
All of the action is in the HF section of the 4430 passive crossover, it seems, which stays in play when biamping.

Yep!

I did a spice analysis with the AM6212 xover but do not have it here. I can post it tomorrow. There was one or two notch(es) to tame the response peaks. If we succeed with implementing these into the 4430/4435 networks that's the ticket! :)

I still didn't start my 4435's. :bouncy:

Guido
02-26-2005, 11:57 AM
The 2431 is an improved 2430 and offers better high frequency response. It has an improved surround.

Ha! I was wondering why the 2430 and 2431 had the same price till mid 2004 and then suddenly the 2431 price where rised by 100 USD. Now I understand :D

Zilch
02-26-2005, 12:12 PM
I did a spice analysis with the AM6212 xover but do not have it here. I previously cited your earlier exchange with Giskard regarding AM6212 crossover topology here:

http://audioheritage.org/vbulletin/showthread.php?t=2175

It seemed incomplete and I couldn't quite follow it. I'd say it's worth a new look and update, now, yes! :D

Guido
02-26-2005, 12:24 PM
Tomorrow I'm back home and then I will assist. Let's go for it :bouncy:

Zilch
02-26-2005, 12:38 PM
Let's go for it :bouncy:Yup. Order up some drivers and horns, too. Let me know if you still can't get them. Sim is one thing, actual gear, quite another.

YUM! Tasty.... :D

Earl K
02-26-2005, 12:59 PM
Hi Zilch ( et al)

I'm all "eyes and ears" with this thread . Sometime in the future I may need to invest in a quantity of 3" diaphragm drivers. So your work ( and Widgets ) on measuring the 2431h is much appreciated by myself .

FWIW ; as a matter of comparison, I'd love to see its' response measured when used as a direct "swapin" on a H9800 / with the "tweaked for 435Be" network .

Personally, I wish JBL would offer a Titanium diaphragmed version of this 3" driver with the "aquaplas dusted" option . ( Just wishing )

:cheers:

Zilch
02-26-2005, 04:37 PM
Feel free to contribute your expertise at any time.

For example, how important is it that we maintain the 4430's 15-1/2" center distance between 2235H woofer and whatever mid/high compression driver/horn we end up using?

This is achievable in L200 using either the OASR horn or rectangular PT waveguide, but not the larger square PT waveguide, the P-Audio horn, or the 2344(A).

And to where on the drivers do we measure to get the time alignment right? See the driver pic here:

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=12&p=44254

We're dealing with major differences in horn/driver assembly depth....

Zilch
02-26-2005, 04:49 PM
Auditioned dbx DriveRack PA and Behringer UltraCurve DEQ2496 today.

DriveRack PA, $499, a better, more comprehensive unit including crossovers, but the tiny screen is impossible to read; no option to connect to laptop for reasonable viewing. Not intuitive, either. Pass.

UltraCurve DEQ2496, $299 on sale at Guitar Center. None in stock, except the one in their demo rack "never even plugged in." $285 with NIB $70 ECM8000 testing mic and free input, output, and 20' mic cables. Surprisingly, sales person actually knew what it was.

SOLD to the Zilchster. Thank you Leon! :)

[Enough $$$ left over to buy cat food, urgently on the list....]

Earl K
02-26-2005, 05:10 PM
And to where on the drivers do we measure to get the time alignment right? See the driver pic here:

- I always "time-align" when biamping, by utilizing a crossover that has a delay on the woofer section ( since the horns' diaphragm is just about always behind the woofers voice coil ) . I use 3 sinewave tones ( generated by a Behringer 8024 , plus some pink noise ) to look for the "best fit" ( with the 8024 acting as an RTA ) while I adjust the delay function of the crossover. As such, I really am completely ignorant of whether or not I'm electronically re-aligning the physical displacement of the two voice-coils - or - re-aligning 2 displaced acoustic centers ( not necessarily the same thing & therefore not really repeatable with a tape-measure and marking tape ). If I was you, I'd hang out as much as possible with Mr. Widget and try to get him to solve this question ( is it voice-coils or acoustic centers that are being re-aligned ? ) He now has the necessary gear to answer this question.


:cheers:

johnaec
02-26-2005, 07:48 PM
DriveRack PA, $499, a better, more comprehensive unit including crossovers, but the tiny screen is impossible to read; no option to connect to laptop for reasonable viewing. Not intuitive, either.I've got the Driverack 260 - the step up from the PA/Studio. 'Far more comprehensive options than the PA/Studio, and 'can also be controlled via laptop. I think it's intuitive once you get through the initial setup, but I think all these processors could be more so...

John

Ian Mackenzie
02-27-2005, 05:33 AM
Feel free to contribute your expertise at any time.

For example, how important is it that we maintain the 4430's 15-1/2" center distance between 2235H woofer and whatever mid/high compression driver/horn we end up using?

This is achievable in L200 using either the OASR horn or rectangular PT waveguide, but not the larger square PT waveguide, the P-Audio horn, or the 2344(A).

And to where on the drivers do we measure to get the time alignment right? See the driver pic here:

http://audioheritage.org/vbulletin/showthread.php?t=3838&page=12&p=44254

We're dealing with major differences in horn/driver assembly depth....

Its a bit of a riddle. I you don't have access to time alignment tools and there is significant difference in path length then in theory moving the horn away from the woofer will reduce the angle of the off axis lob around the crossover region. However the distance b/n the drivers spacing is best kept under D= wave length at the crossover point.

In the case of the 4430 I think they got it was close as practical and designed in 15 degree vertical upward polar title for inverted mounted.

I found that moving the horn in the horizontal and vertical domain effected the crossover transition amplitude response but this could also be tweaked wit adjustment of the C values on the woofer or horn.

Ian

Zilch
02-27-2005, 01:18 PM
I THOUGHT it was simple triangulation....

Gotta read between the lines of the hype to figure out what's actually going on. :)

Zilch
02-27-2005, 05:54 PM
Behringer UltraCurve does its AEQ (auto-equalization) thing. System F (2431H's on PT Waveguides, 4430 crossovers at max boost,) gets "room correction" (-1 dB/octave) option enabled for the garage. Once it's finished, I find myself boosting the bass further, 'cause I been listening to SUB1500 too long. B380's take it in stride. :p

U/C "begs off" Auto EQ below 100 Hz, anyway, (though you can force it to do it,) "because it is this range that may produce inaccuracies during the calculation of the frequency response, which might impair the result achieved with the AUTO EQ." Fine. I do it myself.

I was concerned initially that pink noise might only be available in the AEQ function, but it can also be manually engaged from the I/O menu with just two clicks. Now I have to figure out how to do each channel individually, if possible. Response varies substantially depending on mic position when both speakers are playing noise, probably due to phase cancellations.

Most correction occurred at 8 kHz, as predicted, where U/C attenuated -3.5 dB. Giskard's info regarding similar design 2435 may apply to these drivers as well; they don't start rolling off until after 7 kHz, maybe, so standard compression driver compensation below that overdoes it.

As hoped, U/C allows reading the actual correction in each band via moveable cursor, but the resolution is only two digits. We'll term it "ballpark." More than that, we'd need a significant sample of drivers for it to be meaningful, anyway.

Again, it's clear we're good at least to 20 kHz, maybe beyond, with this driver/horn combination.

UltraCurve Pro DEQ2496 is a way fun deal. You can watch and hear it do its correction as it's happening. And watching the RTA with program material playing is better than most TV. :D

[Gotta figure out how to more competently photograph it, tho....]

Guido
02-28-2005, 03:24 AM
Yellow = 4430 set to 0
Green = 4435 set to 0
Blue = AM6212_00

Easy to see that the area around 7 kHz (b) is EQed out in the AM network.

(a) = crossover frequency at 1 kHz

Robh3606
02-28-2005, 07:31 AM
"Once it's finished, I find myself boosting the bass further, 'cause I been listening to SUB1500 too long. B380's take it in stride. :p "

Neat Huh!!! That auto EQ can work real well. I do the same I have my subwoofer levels up to give me a rising response from say 40/50hz down. Sounds like it's missing something if it's totally flat. I take my photo's using on a tripod. Using my hands is hit or miss. Attached are both channels driven with the 4435 crossover using 2344's with 2416's You can see the roll off very easilly. There is some microphone roll off but it primarilly at 20K. Your driver and horn combo looks better up high.

Rob:)

Guido
02-28-2005, 10:14 AM
Auto EQ ??

HE! Let's do it old school :p

Zilch
02-28-2005, 10:36 AM
Guido: Auto EQ (SO cool!) is telling us what the passive has to do with these drivers, and it's saying the same thing as your curves, some reassurance that what we've learned so far is not a random anomaly. We'll confirm that with actual measurements of the drivers themselves. My next step will be to try with the AM 6212/00 crossover topology.

Got parts ordered? This a a Global Village endeavor!

Rob: Thanks for the tripod tip. Yup, "hit or miss" is what I get here. :p

It DOES look like this horn/driver combination is a significant step up, but you might want to wait until there's been more than just me listening to it, as itza $1000 (list) upgrade. We've gotta measure distortion in the HF region, too. It may be that we're pushin' it too hard up there.

What's the vertical scale on your RTA shown?

Robh3606
02-28-2005, 12:05 PM
"What's the vertical scale on your RTA shown?"

Mines set at 1dB per tick. What can you do on the 2496?? The 8024 only gives you 2 choices .5 and 1dB. I would have liked a selectable scale more like Widgets RTA. What does the EQ curve look like??

Rob:)

Zilch
02-28-2005, 12:22 PM
What can you do on the 2496?? U/C 2496 is 0.5 dB per tic. RTA display resolution is variable. I'm showing 5 dB per major division (the dotted horizontal lines) above. Full scale, then is 30 dB.

Choices are 15, 30, 60, and 90 dB FS. You also set the max shown (the top line), which is adjustable from 0 to -60 dB in 5 dB increments. It'll display somebody a block away flushin' their toilet, if desired. :D

Didn't take a pic of the EQ curve (DUH!). After dark tonight, then.

Earl: 1 kHz wavelength is 13.56", a do-able deal in L200 box, probably. We certainly don't want upward tilt, as the baffle board is already angled up....

Zilch
02-28-2005, 11:17 PM
What does the EQ curve look like??Well, there's a dilemma. I know for a fact that small movements of the mic when both channels are playing pink noise move stuff all around on the RTA, likely due to phase cancellations. So, the question is, "Can you get an accurate auto EQ doing both channels at once?" Seems it would only be valid for the mike position.

U/C has a "Dual Mono" mode that lets you save separate EQ curves for left and right at the same time, after running them separately. Cool. I try it. Stupidly, it plays pink noise outta BOTH channels while doing auto EQ on each. Fine, so I shut down the right channel while doing the left, and vice-versa, aiming the mike at the active channel. Results below, along with the curve from doing both channels concurrently. Very little difference. DUH! How do it KNOW? It's smarter than your ordinary Zilchster, apparently. :p

Bear in mind that these are corrections the U/C makes with 5235 and N3134 crossovers (all boosts at max) in the path, NOT corrections for the raw 2431H drivers.

Finally, reassurance for the mighty Giskard, his 2235H's now safely ensconced behind the glue-blobbed vintage L200 grille screens. Apparently, there's no dust where he lives; these look like fresh recones.

Installing them, I discovered there's NO bracing on the back of the front baffle (one rattle fixed with Gorilla Glue outta a hypodermic), largely due to port locations there. Gonna have to transverse triangular brace to the rear corners, probably, like yggrdrasil did here (http://audioheritage.org/vbulletin/showthread.php?t=4950&p=44780), once I'm finally done "messin'" with 'em. Don't think I'd put Sub1500's in these boxes.

[Sound purty good as B380 equivalent subs, tho....] :D

4313B
03-01-2005, 12:38 AM
Apparently, there's no dust where he lives; these look like fresh recones.They've never been reconed. Those are factory originals. I did blow them off with compressed air though. :p The boxes I shipped them in are the recone kit boxes for Mike's 2235H's he just bought from a guy in Michigan who claims his 4430's were from a very famous former JBL engineer.

Zilch
03-01-2005, 01:48 PM
AM6212/00 crossover topology recognized by forum member Guido nearly a year ago as potential 4430 enhancement drives 2431H on PT waveguides. Two units on pink noise at ~1M shown on RTA in averaged mode, I suspected one was "hotter" than the other, but I don't know yet if it's the horn or the driver.

Scale is 2.5 dB per dotted line. They shouldn't let us have measurement devices like DEQ2496, probably. Too easy to see what's goin' on with stuff, like manufacturing variability and defective units.

How much of this is room response? How do I get more "anechoic," move up to like 6"?

I think I know what I'm doin' next -- another one of these.... :D

Guido
03-01-2005, 02:34 PM
AM6212/00 crossover topology recognized by forum member Guido nearly a year ago as potential 4430 enhancement drive 2431H on PT waveguides.

I just couldn't try it without the horns :banghead:

Today I got again bad news. JBL cancelled all orders for the 12x12 waveguides! Reason is their fear from copys. That's so stupid. All the far east copy cats will by an AM Speaker and then they will have the horns anyway :banghead:

Zilch, looks like you need to penetrate them for 2 more horns :D

Zilch
03-01-2005, 02:43 PM
JBL cancelled all orders for the 12x12 waveguides! Reason is their fear from copys. That's TOO silly to be true. It's not as if they haven't had the same potential (and real) problem with all of their designs.

They're big boys, and know how to protect technology. Locking everybody out will GUARANTEE they'll be replicated.

I'll try to order up a couple more here....

Guido
03-01-2005, 02:54 PM
I'll try to order up a couple more here....

:bouncy: :bouncy: :bouncy:

We should spam them with orders :p

Zilch
03-01-2005, 05:26 PM
We should spam them with orders :pNow, Guido, let's not overreact.

We don't even KNOW if they're worth a damn yet. ;)

Earl K
03-01-2005, 06:38 PM
Hi Zilch

Back to your question ; re 2235 to horn distance .

- Once I started working with 24db/octave LR electronic filter slopes I had to move horns ( in boxes ) as close as phsically possible ( within 1/2" sometimes ) to the woofers edge. I find this gives the best cohesion for the highish points that I use ( @1200 hz ).

- BTW , I don't think its' the center to center distance that's so important with a horn /woofer combo , as much as the marrying of the two polar plots.
A horns coverage angles are determined by its' 6db down points ( for most frequencies wthin the midband ) while a woofers' polar patterns' 6 db down point shifts upwards with with frequency. ( This is definately a "What Ian said" sort of comment . )

Center to Center :
- Out of interest you might want to explore the reasons for the distance spreads found in the 4343/44/45 series of boxes between the woofers and the ten inchers. Then relate them back to the actual filters being used in each box type .

- I'm still not sure what to suggest you do with your L200 boxes. ( I've always liked two box systems )
- I guess that question has a lot to do with your recent explorations , correct ?

:cheers:

Zilch
03-02-2005, 01:35 PM
- I guess that question has a lot to do with your recent explorations , correct?Yup, trying to figure out the parameters here, particularly for the L200 modification. It's pretty clear to my ear (and the RTA) here that the 1.5" drivers on PT waveguides are a significant step up. We've got more testing to do before the decisions are made, though.

From what I've been able to figure so far, as long as the combination behaves as a coherent source (alleged virtue of 4430 is that beamwidth of woofer and horn are the same at the crossover frequency), a wider spacing reduces time alignment issues. The closer the drivers are, the more coincidence (equal path lengths) is "aimed" by time alignment. That hasn't led me to any conclusions yet, but it tells me what to try using the RTA. Frequency nulls and how they move are plainly visible.


I just couldn't try it without the horns http://audioheritage.org/vbulletin/images/smilies/banghead.gif Again, try it on your P-Audio horns. You will NOT be disappointed. Trust the Zilchster on this now. That's what's playing here, just to confirm it for you. We're gonna have to tweak the HF crossover point down a little (to 1 kHz, maybe, if 2431H will play that). There's a notch at 1 kHz, 'cause 2235 won't work up to 1.2 kHz very well (max recommended crossover frequency 1 kHz).

I'm playing 2235's with no crossover to let them go as high as they will. Maybe if I put the 4430's Zobel back in the LF, they'd play a little better above 1 kHz and fill the notch. It's not a difference I can hear, but it's visible on the RTA. I'm reluctant to EQ it out, as 2235 would be boosted in its "bad" area. Also, AM6212 crossover will prevent any EQ at that frequency going to the 2431H's, probably, but you're more familiar with that part from your earlier work with it. Any suggestions? Like you, I'd like to make the straight passive work without additional EQ. This is gettin' VERY close....

Zilch
03-02-2005, 09:42 PM
Mating Giskard's 2235H's in retuned L200 cabinets with 2431H's running on 12" square PT Waveguides and HF section of AM6212/00 crossover (http://www.jblproservice.com/pdf/AE%20Series/AM6212,00-WH.pdf) (5 components). 2235's are running full range, biamped. "Presence" is adjusted simply by the relative attenuation of HF vs. LF amps. Run totally passive, a single L-Pad would do it, like in the "olden" two-way days. :p

The best-sounding system assembled thus far (including full-blown 4430 emulation), I ran them most of today with 2435H's (Be diaphragms); they also work fine with this crossover topology, according to RTA.

Both driver types (Al & Be) apparently incorporate new two-stage phase plug and dome design, which shifts rolloff up to 7 kHz rather than ~3 kHz of earlier drivers. Less compensating EQ boost is required with these, and HF distortion is allegedly therefore lower. 4430 pushed 2425H harder in boosting the HF.

More info here @ Fig. 29, 30, & 40, also text description of 2435 at #7:

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

Yes, I can hear the difference, but wait for measurements to confirm this. The tradeoff seems to be LF response. I doubt these would play down to 500 Hz, though Giskard asserted earlier here that, with a larger back cup, they'll do 800 Hz very nicely....

Zilch
03-02-2005, 09:54 PM
Four-bolt 1-1/2" PT Waveguides may be mounted via JBL thread-on throat adapter to varous 1" drivers such as LE85 (with thread adapter, left), 2418H-1 (right), and exposed "snoot" of 2426 or 2427 (rear).

A two-piece assembly, as TimG observed, adapter incorporates engineered compound race-track oval throat constriction similar to that in the waveguides themselves, and alignment studs to establish the requisite orientation. With waveguide mounted, there are double constrictions, yes.

Note safety gear in top photo. ;)

Guido
03-03-2005, 03:25 AM
Four-bolt 1-1/2" PT Waveguides may be mounted via JBL thread-on throat adapter to varous 1" drivers ;)

What is the part number please?

Guido
03-03-2005, 03:38 AM
I'm playing 2235's with no crossover to let them go as high as they will. Maybe if I put the 4430's Zobel back in the LF, they'd play a little better above 1 kHz and fill the notch. It's not a difference I can hear, but it's visible on the RTA. I'm reluctant to EQ it out, as 2235 would be boosted in its "bad" area. Also, AM6212 crossover will prevent any EQ at that frequency going to the 2431H's, probably, but you're more familiar with that part from your earlier work with it. Any suggestions? Like you, I'd like to make the straight passive work without additional EQ. This is gettin' VERY close....

We should wait for widgets mighty measures ;)


Basically I would go with the 4430/4435 crossover but modify the HF part such as the boost around 7kHz is lower. See my voltage drive curves. I'll try to figure this out tonight with my spice program. Will post the results when you having lunch :)
Could you please post (again) a detailed RTA with the 4430 crossover and 2235 and 2431+Waveguide without ANY correction of this digital doohickey?

We should take into consideration the 4435 too as this is my next project :p

BTW:
I need 4 such adaptors (mentioned earlier here):

http://store.steelsound.com/Detail.bok?no=428

They are not available here in Germany. I mailed them but no response. Seems the order is too small for them.
The P-Audio PC25 does not work as it adds 2cm in length!

Who can help? I pay with paypal instantly.

Zilch, maybe you can ship them together with the Waveguides if you'll get them?

Earl K
03-03-2005, 04:13 AM
Guido

- It looks to me that Steel Sound is still in the process of building that web-page. I'm sure you can get some help on a purchase like that .

- That's a different page from the one found at my last visit ( January maybe ).

- I'd just give it a bit more time and try buying from them again .

- Did you try to purchase through the automated "shopping cart" ?

- Or did you just send an email ?

- ( I also think you should buy some of these small round/square horns - just because they're cheap - $ 7.00 ?? )


BTW Zilch,, great thread ! :D

stevem
03-03-2005, 07:56 AM
I have a question about the best dispersion pattern for a listening room. I used to use 2344A horns with 2426H drivers with their 100 x 100 degree dispersion. I switched to 2450SL drivers with 2332 horns which I think are 100 x 40 (?) degrees. While I greatly prefer the sound of the 2450SL, I liked the wider dispersion of the 2344A. In JBL's manual for the KS S9800, they make a point of saying a 60 x 30 degree coverage pattern is ideal. This also makes me wonder if the 90 x 50 or 60 x 40 PT waveguides wouldn't be a better choice. Anyone have any thoughts on this?

Earl K
03-03-2005, 08:11 AM
Anyone have any thoughts on this?

I choose a horns' polar pattern based on keeping its main "in-band" energy output away from the listening rooms' side walls ( and ceiling ) - as much as possible.

Or put another way - I make sure the horns measurable 6 db down points are radiating towards the walls.

This usually means mapping it all out on paper using a simple CAD/Draw program .

:)

Zilch
03-03-2005, 09:27 AM
In JBL's manual for the KS S9800, they make a point of saying a 60 x 30 degree coverage pattern is ideal. This also makes me wonder if the 90 x 50 or 60 x 40 PT waveguides wouldn't be a better choice. Anyone have any thoughts on this?I'm pursuing the 100 x 100 because I have found the 4430's pattern fits the way I listen. System A in this project was 2370A with a 40 x 120 pattern, and I found it too restrictive immediately. I don't have a "listening room" per se, and often, I'm not the only listener, so a "sweet spot" doesn't apply here. I want everybody on the couch, in the room, and in other rooms (which, often, is me) to enjoy the same fine JBL experience. :p

Indeed, if I had a fixed HT setup, as Earl suggests, I might make a different choice. The horns (I keep calling them "horns" out of habit, but the "waveguide" term is, indeed, more appropriate, since they are quite flat, not at all what we traditionally think of as horns,) are relatively inexpensive, and I guess having several different patterns on hand might be a reasonable option. TimG is studying a different pattern; hopefully he'll report his findings here soon....


What is the part number please?The JBL PT waveguide to 1" threaded throat adapter is 339308-001. I'll get you the fresh RTA plot later today. You need to PM me regarding purchasing....

Guido
03-03-2005, 02:11 PM
Will post the results when you having lunch :)


OK, will wait first for the RTA.

Alex Lancaster
03-03-2005, 02:17 PM
:) Zilch: I thought this was going to be "Quick", but keep on going :p .

Guido
03-03-2005, 02:31 PM
:) Zilch: I thought this was going to be "Quick", but keep on going :p .

Alex! Oh No! Do not stop him :bash:

stevem
03-03-2005, 03:12 PM
I'm pursuing the 100 x 100 because I have found the 4430's pattern fits the way I listen. System A in this project was 2370A with a 40 x 120 pattern, and I found it too restrictive immediately. I don't have a "listening room" per se, and often, I'm not the only listener, so a "sweet spot" doesn't apply here. I want everybody on the couch, in the room, and in other rooms (which, often, is me) to enjoy the same fine JBL experience. :p

Indeed, if I had a fixed HT setup, as Earl suggests, I might make a different choice. The horns (I keep calling the "horns" out of habit, but the "waveguide" term is, indeed, more appropriate, since they are quite flat, not at all what we traditionally think of as horns,) are relatively inexpensive, and I guess having several different patterns on hand might be a reasonable option. TimG is studying a different pattern; hopefully he'll report his findings here soon....


I feel the same way about the dispersion pattern of the 2344A, even though I listen in a room that would charitably be called "difficult". I would think that with my 7'2' celings, the narrower dispersion horns would be better, but I miss the more open sound field I used to have. I have already ordered a pair of the 100 x 100 PT (rotatable) wavequides, so I'll let you know what I think from a subjective standpoint. I do have some measurment equipment, but I am certainly no audio engineer (although I did sleep at a Holiday Inn Express last night!). The parts person I ordered them from did not say anything about not shipping for any reason. I'll let you know when they arrive. You're right about the price, it wouldn't be much of a hardship to try one of the other flavors. What are these things made of, plastic or metal? I'm thinking I will have to drill holes for my 2450SLs, as the bolt pattern is not the same as the 2451. Do they seem to project a similar sound field as the 4430 horns do? Thanks!

Zilch
03-03-2005, 04:23 PM
What are these things made of, plastic or metal? I'm thinking I will have to drill holes for my 2450SLs, as the bolt pattern is not the same as the 2451. Do they seem to project a similar sound field as the 4430 horns do? Thanks!They are made of a material similar to 2344, i.e., reinforced plastic, black. You can easily file the mounting holes into mounting slots with a rattail file.

I'd describe the sound field as "broad" like 4430, but we won't know for sure until Widget does polar meaurements on them. They sound similar to, but perhaps more "up front" than, i.e., not as "transparent" as, 2344A, but there's lots of out-of-control variables here, such as the reverberant field of the garage. :)

Zilch
03-03-2005, 04:40 PM
Rectangular PTF waveguide (square is PTH) assembles to 1" throat 2418H using JBL adapter, as, for example, used in AC2215/00 (http://www.jblproservice.com/pdf/AE%20Series/AC2215,00-WH.pdf) and others. Drivers such as 2426/7 and adapted LE85 w/threaded "snoot" (shown behind) will fit, too. As suspected, studs on adapter align the engineered throat constrictions, vertical on the adapter, horizontal on the waveguide.

2431H and 2435H mount directly to the waveguide for a comparatively shallow assembly, just 2.5" from mount surface to driver, 4.75" overall depth. Note 100 H x 100 V pattern spec embossed on the face.

[Too much STUFF on the bench, now.... :p ]

Zilch
03-03-2005, 04:49 PM
Rectangular PTF waveguides on 2431H neodymium drivers sound similar to PTH square version. Allegedly, they have reduced distortion, though less controlled vertical field than PTH. I dunno, we'll have to wait for measurements, as we're into the realm of the impreceptible for the Zilchster here....

Zilch
03-03-2005, 04:59 PM
:) Zilch: I thought this was going to be "Quick", but keep on going :p .I won't disappoint on the "Dirty" part, presumably.... :D

Earl K
03-03-2005, 05:04 PM
NICE ! ( a very Handsome WaveGuide )

Remind me please ,

- What frontal dimensions did you say those rectangular guides were ?

:cheers:

Zilch
03-03-2005, 05:15 PM
- What frontal dimensions did you say those rectangular guides were ?They're 12" W x 6-1/2" H, outside dimensions.

I know other forum members have them. Hopefully they'll chime in with their impressions.

[They could do with a little paint, for sure.... ;) ]

Earl K
03-03-2005, 05:47 PM
Thanks Zilch

- I just went through all 6 pages of this thread - unless I missed it / that was the first mention of that horns', outside dimensions ( & I ain't going back to double check that statement ) .

- What I don't understand is the interplay between the proposed systems comprisng either the B380 or the L200 enclosure as the LF module .

- Are you trying to choose the best and get rid of the other ?

- Or are you trying to find the best match of horns/drivers/passives to put over each box ?

- You know , it seems nobody worldwide gave 2 hoots about the lowly L200 until you threatened to cut the baffle board. "Fair-Weather Fans" I say.
Personally, I'd execute the extra effort and install a removable top baffle board - starting just above those 2 ports. The 4343 , 4 ways have this - though it's a bitch to remove. I'd put T-Nuts into a backing 1"x2" rectangular recessed frame, along with weather stripping to create the seal. A removable baffle allows you to restore ( more or less ) to the original configuration .

It's a 3 penny thought <> :cheers:

Zilch
03-03-2005, 06:37 PM
- What I don't understand is the interplay between the B380 systems and the L200 systems .The "Manifesto" is somewhere back there early on, I think. ;)

1) Can you make a "Quick and Dirty" quasi-4430 outta B380? That was the initial post.

2) In the course of doing that, is what you learn applicable to upgrading L200 as a two-way system?

3) And finally, as concomitant benefit, can you also discover ways to "sweeten" 4430, particularly DIY versions?

We are demonstrating that the answer to all three is "Yes," I think, and learning a buncha other relevant stuff along the way, presumably in an organized fashion. We're also not afraid to incorporate newer technology, where warranted, and as applicable.

The "Lowly" L200, same size box as 4430, affords the opportunity to have a hella good upgraded two-way (itself a challenge) in a very handsome vintage package, a worthy endeavor. They can be had for $500 - $600 complete, and cabinets alone for under half that. It's respectful of the heritage to renew it, I believe. Call it "adaptive reuse."

B380, comprising an approximation of the low end of 4430 (and, in some ways, a better one for home use,) provides a test platform and comparison standard for various alternative configurations and potential upgrades. It'll likely end up as a two-box system incorporating whatever enhancements we develop here. Panos posted an appropriate model:

http://audioheritage.org/vbulletin/showthread.php?t=4915&p=44324

The moderne one, not the organic one. :p

The LF could be B380 (or equivalent) there, in lieu of the bass horn. If somebody without L200's wants to build the system we're defining here from scratch, it's easily accomplished.

Finally, there is the inherent satisfaction of counterpoint. :D

[Delicious!!!]

Mr. Widget
03-03-2005, 09:36 PM
- You know , it seems nobody worldwide gave 2 hoots about the lowly L200 until you threatened to cut the baffle board. "Fair-Weather Fans"

I was not joking when I offered to build a pair of replacement cabinets in exchange for those mint L200s.

Zilch, I guarantee mine will be Sub1500 proof as well and you can have them in walnut, maple, cherry, or any other wood veneer that is in that price range.

Widget

Zilch
03-03-2005, 10:01 PM
... and you can have them in walnut, maple, cherry, ...:hmm:

We'll talk.

[It'll require compound mitres, tho....] :)

Zilch
03-03-2005, 11:26 PM
RTA in "Average" mode, GEQ flat, 2.5 dB per dotted line.

First, N3134 controls set to "0," i.e., HF at 4:00, MF at 12:00, with closeup.

Then, all controls set to max, and closeup.

[Dunno WHAT's up with the LF there. Somethin' hummin', probably.]

Does this make sense? Yes. Too much boost above 7 kHz.

Can't dial it down without losing VHF at 20 kHz, too....

Guido
03-04-2005, 03:37 AM
I played a bit with my spice program.

I didn't come any further with modifiying the 3134 network.

My recommendation is to take the LF part of the 3134 for the 2235H and to take the HF part from the AM6200 but bring in an 8 Ohm L-Pad BEHIND the parallel RLC!
Maybe we have to shift this RLC a bit but we will see...

Green is 3134 set to "0"
Yellow is AM 6200 network with L-Pad behind RLC set to app. "3:00" or Rs=2 Ohms and Rp=24 Ohms

This should work well.

Please try it. :bouncy:

Earl K
03-04-2005, 08:41 AM
I was not joking when I offered to build a pair of replacement cabinets in exchange for those mint L200s.

Zilch, I guarantee mine will be Sub1500 proof as well and you can have them in walnut, maple, cherry, or any other wood veneer that is in that price range.


:)

Zilch
03-04-2005, 01:18 PM
A minor glitch. Factory crossovers use 2.5 ohms for R1, not 4.0 Ohms. DUH!

C2 remains 6.0 uF

Value of L4 is unknown, and no LCR meter here. Hopefully Widget has a way to read it at the audition tomorrow....

[He'll be busy hosting, tho.... :cheers: :dancin:]

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 ]

Mr. Widget
03-04-2005, 02:21 PM
Bring your coils and check 'em out... we offer full service here at the Works.

Widget

Zilch
03-04-2005, 03:34 PM
I feel the same way about the dispersion pattern of the 2344A, even though I listen in a room that would charitably be called "difficult". I would think that with my 7'2' celings, the narrower dispersion horns would be better, but I miss the more open sound field I used to have.Why they work for us is here, I believe:

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

We WANT that combination of direct and reflected sound. Others want to minimize the reflected part. Both are perfectly valid preferences....

Zilch
03-04-2005, 10:42 PM
N3134 (4430) crossover schematic says Zobel is retained in the LF circuit in external (biamp) mode. N3135 (4435) crossover drops it, apparently.

I'm running 2235H's full range to fill the notch between 1 kHz LF and 1.1 kHz HF crossover frequencies revealed in initial tests with AM6212 HF crossover. Would adding in the Zobel help the situation?

First RTA plot in "average" mode shows response running full range.

Second is with Zobel in circuit. Apparently, JBL 6260 amp running the 2235's doesn't give a whit about 2235 impedance.

Third is N3134 low filter kicked in. Ooops! Notch City. It MATTERS. We'll have to move one or the other of the crossovers' frequencies to close the gap if we're going to retain N3134 low filter as Guido suggests. Whether 2431 will play lower remains to be determined. JBL don't do it anywhere I've seen.

Last two plots show full range vs with filter at lower resolution. The notch is 12 dB deep. We can't ignore it; it's quite audible when switched in and out.

Guido
03-05-2005, 08:32 AM
Last two plots show full range vs with filter at lower resolution. The notch is 12 dB deep. We can't ignore it; it's quite audible when switched in and out.

Might be a polarity issue?

2426 (4430 original) is negative, 2431H most probably positive.

In any case I suggest to keep the LF part conencted to the 3134 network as it is designed for the 2235.

I'll rework my curves for the AM 6200 modification and post shortly. Will correct the R1 value