Quick & Dirty 4430-Inspired Two-Ways Part I

[Zilch]

I'll PM you the details....

[Ian Mackenzie]

I think P Audio make a 1 inch version



Ian

[Guido]

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

[Robh3606]

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]

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/M...s%20Manual.pdf

[Zilch]

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!

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]

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.

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]

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






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


Net Weight (kg)
0.85
Gross Weight (kg)
1.15
Pieces per carton
1
Volume (cuft)
0.46
Dimensions (cm)
25x25x21

[Zilch]

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]

There's also the 2430H.

John

[Zilch]

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]

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]

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 ém in the mail for the EQ.

Ian

[Zilch]

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.

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....

[Zilch]

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?