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?
Printable View
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?
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)?
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:)
The schematic is here:Quote:
Originally Posted by Robh3606
http://www.jblproservice.com/pdf/Stu...ies/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?
Hello Zilch
Ian had a couple of good post's in this thread have a read.
http://audioheritage.csdco.com/vbull...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:)
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:
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:Quote:
"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."
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:)
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.Quote:
Originally Posted by Robh3606
Widget
The 1'' baffle space optimises the smooth crossover transition at 1k Hertz.
Ian
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?Quote:
Originally Posted by Robh3606
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.... :)
Post 'em here in "Marketplace" first with some nice pics. The forum is getting regular traffic these days....Quote:
Originally Posted by stevem
Agreed. If measured from the correct listening height.Quote:
Originally Posted by Ian Mackenzie
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
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
Indeed, the mighty Giskard suggested in an earlier thread, (the genesis of the L200/4430 conversion idea):Quote:
Originally Posted by Robh3606
"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.... :)
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
I'll PM you the details.... :)
I think P Audio make a 1 inch version
Ian
No, only 1,5" available!Quote:
Originally Posted by Ian Mackenzie
I think they where a little concerned with copyright issues :cool:
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:)
It was scanned last night and should be up later today under Vintage Product.Quote:
Originally Posted by Zilch
*****
http://www.jblpro.com/pub/obsolete/M...s%20Manual.pdf
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....
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/.../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/s...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:
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.Quote:
Originally Posted by Zilch
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/product...ifications.gif
Description
HORN
Throat Diameter (in.)
1.0
Crossover Frequency (Hz)
600.0
Nominal Coverage Angle (°)
90°x90°
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
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?
There's also the 2430H.
John
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....
What about the 5233s with 1200 Hz FFBREQ cards. Do they have the same problems as the M552 as far as high freq EQ?Quote:
Originally Posted by Robh3606
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.Quote:
Originally Posted by andresohc
If you need I we can measure up some coils and chuck ém in the mail for the EQ.
Ian
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 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/s...ead.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....
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.Quote:
Originally Posted by Zilch
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.
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
First, the reference. This is 2425H on 2344 horn, no network.
Red on axis, blue @15°, green @30°, purple @45°
Red = on axis
On axis, Red=PH-316, Blue=2344
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:)
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
'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:)
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. :pQuote:
Originally Posted by Robh3606
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:
"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/vbull...lies/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:)
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:)
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
Well, d'UH! :rolleyes: :rolleyes: <---- (Zilch & Widget)Quote:
Originally Posted by Ian Mackenzie
We'll plan on trying that on the next round of tests, when the other drivers and horns get here.
The mounting pattern is different. Didn't want to hack up the TADs QUITE this soon. :pQuote:
Originally Posted by Ian Mackenzie
[Ian thinks outside the box. GOOD stuff!!]
Just discovered JBL makes a horn adapter for using PT Waveguides with 1" drivers.
[MORE options....] :D
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
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
A walk down memory lane - my first non-exponential horn system.Quote:
Originally Posted by Zilch
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. ;)Quote:
Originally Posted by Zilch
RED = Stock B380 without BX63
GRN = Stock B380 with BX63
BLU = Stock B380 B6 tuned and assisted
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.Quote:
Originally Posted by Giskard
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
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:Quote:
Originally Posted by Giskard
Quote:
Originally Posted by Zilch
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
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
31xxA Curves as published by JBL:
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:
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.... :(
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:)
Thanks, Rob! Maybe we can track down some 4344/4345 cards to swap here. :D
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:
Thank you, Earl. I'll look that up!Quote:
Originally Posted by Earl K
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.... :)
0°, 15°, 30°:
0°, 15°, 30°:
'Any idea of what adapter he used to go from 1" to 1.5"?
John
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
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....Quote:
Originally Posted by johnaec
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%...2212,64-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.
I have 3 horns coming:Quote:
Originally Posted by TimG
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.
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 ]
And they really told you they are available??Quote:
Originally Posted by Zilch
Hi, Guido!Quote:
Originally Posted by 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....
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....
3110A voltage drive simulation courtesy of David Smith. :cheers: 08-FEB-2005Quote:
Originally Posted by Zilch
You should already have my 4430 and 4435 voltage drive sims.
They've been posted several times.
Way COOL! Ontogeny recapitulates phylogeny here, apparently.Quote:
Originally Posted by Giskard
Yup, I have the 4430/35 sims. How about N200B? Izzat available anywhere?
Yeah, a primary objective is to convert L200 and/or L200B into "Quasi" 4430, which means work with the LE85's that come with.Quote:
Originally Posted by Giskard
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
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.Quote:
Originally Posted by Zilch
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. ;)
Yep, gotta be out of the circuit.
Thanks!
N200B Voltage Drive. Yellow is L-Pad wide open. Cyan is L-Pad at 50%.
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:
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.... :)
"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
This explains it pretty well
Rob:)
Now the other view. Your cards are in transit.
Rob:)
O.K., 0.7598" then. :D
Oh, BOY, we'll have ALL the pieces soon! :bouncy:Quote:
Originally Posted by robh3606
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
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
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..... :)
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 with 2418H crossed at 1.6 kHz, Marquis MS28 with 2412H at 2.8 kHz (MTM center anyone?), Sound Power SP 212-A with 2426H crossed at 1.6 kHz (nice response curves!), smaller SRX Series monitors with 2417H (1.2 kHz) and 2226H (1.3 kHz), CSP18 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.]
OASR under test at Widget Works. Comprehensive tests and measurements with different drivers take less than an hour using CLIO system:
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
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
Here is a plot with no compensation comparing both the LE85 and the 2427 on OASR horns.
Red is LE85
Blue is 2427
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
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
We will ALSO provide refreshing beverages.... :cheers:Quote:
Originally Posted by Mr. Widget
Thank you again for your excellent contributions to this quest! :applaud:
[More horns and drivers are on the way. Heh, heh....]
More info from the forum about the subjects at hand here:
http://audioheritage.org/vbulletin/s...ead.php?t=4731
http://audioheritage.org/vbulletin/s...ead.php?t=1159
http://audioheritage.org/vbulletin/s...ead.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?
Old graphics posts
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....]
Green is 4430 with pads open
Yellow is 4435 with pads open
Cyan is L200B with pad open
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/s...t=3838&p=42483
You should get the card tommorow. How's the hunt going??
Rob:)
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?
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.Quote:
Originally Posted by Zilch
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?Quote:
Originally Posted by Giskard