JBL 2235 with 2450SL and 2332 horn?

I'm wondering if the 2234 or 2235 woofer would be a good match, in a compact (5 cu. ft.) two-way system, for the 2450SL compression driver and 2332 horn?

I had originally thought to find some 1400nd or 1401nd drivers, a la DMS-1, but haven't come across anything but recone kits.

Just concerned that crossing over the 2235 at 1 kHz—the crossover frequency used in the DMS-1—is asking a bass driver to play too much into the lower mid-range. . .

Would appreciate any tips or advice on this matter. . .

4430/5 series achieves this fairly well.

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Originally Posted by grumpy

4430/5 series achieves this fairly well.

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Good to know! Thanks for pointing that out. Shall forge ahead. . .

Hi,

You should be fine with a 4" (2447, 2450SL, 2451, 2452 or 2453) 1,5" driver with SL diaphragms. No real need for UHF with those diaphragms just some tweaking in the DSP. The 243* drivers do not seem to work equally good on the M2 WG

However, M2 is a system with the specific BSS DSP, the JBL settings, the cabinet and the specific drivers. If you alter any of this it is no longer an M2 system and the result will be different.

You may very well like the new system and be very happy with it, but an M2 it is not.

I have tried many drivers on the M2 waveguide (I got my first pair of M2 WG’s in early 2015) and my preference is the 24XX-sl drivers on a stand-alone basis. The Be drivers may sound a little “closer” but the early drop off in frequency and IMHO need for UHF support makes the SL a better choice. However, if you add the JBL M2 factory settings D2 is a better/easier choice unless you spend a lot of time on measuring and testing.

Us mere mortals cannot expect to achieve the same level of system quality as achieved by JBL with thousands of hours work going into the M2 system.

If you have the 4” drivers go with them but expect to put in many measuring hours to get them working. If you need to buy drivers get the D2’s and be done with it.

Having said all that, I build a pair 2-ways with with LE1400H woofers, M2 WG’s with 2450SL cores (476Nd diaphragms), BSS DSP with tweaked JBL M2 settings and they sound wonderful.

I’m also building a system with 2451Be (Truextent) on M2 WG’s and as Iveca said due to them falling off early I’m going to use 045 UHF drivers with them. They will definitely not be M2 clones but have a potential to sound pretty decent.

You choose, easy way with predictable very good outcome = build faithful M2 clones with BSS DSP. Or go you own way and expect quite some man hours and with the possibility to get very good result.

Kind regards
//Rob



Hi,

If you want to cross over that high the 2235 may not be the first choice (2332-2334 should not be used below 1khz) . I budget permits look at the new 2216 driver. If not see if you can find a L14H-2 or 3, they would do a better job at it. DMS1 was dual LE1400Nd’s.

There are several other JBL woofers that would be good choices. And many very experienced people here can surely come with suggestions.

2235 is a dedicated woofer with a heavy cone and as such would benefit from XO lower than 1KhZ. I built a monitor years ago and used a 2118 8” from 350Hz.

If you do decide to go the 2235 route I would recommend to remove the weight ring under the dust cover to turn it into a 2234 that works better for mid.

And while I’m at it you may want to look at a newer horn/waveguide. The 2332 was a good horn back when but today the technology has moved on to waveguides and the difference is rather big. The “horn sound” is gone and it sound more like a big dome but with the clarity and dynamics retained. However, many prefer the vintage sound and I have great respect for that so only you and your ears can decide.

If an option for you, I would suggest to take a look at the VTX F12/F15 (STX825) waveguide. Looks el-cheapo plastic but is in reality very good and really out-guns all of the older designs except maybe M2 for HiFi use IMHO. It also measures very good.

There is lots written here on LH in other threads.

Kind regards
//Rob

Thank you, gentlemen, for the additional comments and information. As it happens, I do have a pair of the STX825 horns. I got them for the D2430K drivers I sourced a couple of years back. Unfortunately, in tests I had done by an experienced speaker designer, they had less HF output than any compression driver I've ever heard. Given all the press and positive discussion about the D2430K, I remain completely baffled by this. Took them to a JBL Service Centre here and the guy told me they were working fine. More bafflement, but for now they're resting quietly in a box in the closet.

I suppose I could mount the 2450SLs on those little plastic STX825 horns if I built some sort of cradle inside the cabinet to take the weight of the driver. And I do have the option of reconing my 2225 drivers with 2235 cone kits and leaving out the mass rings. I also have the option of using TAD TL-1601b instead of 2234/2235s. But not in a position right now to acquire 2216 or other woofers.... Or maybe best to postpone the project until I can afford more suitable woofers such as the 2216. . . Then there's the crossover, but that's a whole other story. I'll probably use my old DriveRack 4820 at least to get things going. . .

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Originally Posted by dubkarma

Thank you, gentlemen, for the additional comments and information. As it happens, I do have a pair of the STX825 horns. I got them for the D2430K drivers I sourced a couple of years back. Unfortunately, in tests I had done by an experienced speaker designer, they had less HF output than any compression driver I've ever heard. Given all the press and positive discussion about the D2430K, I remain completely baffled by this. Took them to a JBL Service Centre here and the guy told me they were working fine. More bafflement, but for now they're resting quietly in a box in the closet.

I suppose I could mount the 2450SLs on those little plastic STX825 horns if I built some sort of cradle inside the cabinet to take the weight of the driver. And I do have the option of reconing my 2225 drivers with 2235 cone kits and leaving out the mass rings. I also have the option of using TAD TL-1601b instead of 2234/2235s. But not in a position right now to acquire 2216 or other woofers.... Or maybe best to postpone the project until I can afford more suitable woofers such as the 2216. . . Then there's the crossover, but that's a whole other story. I'll probably use my old DriveRack 4820 at least to get things going. . .

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If you bought those D2430K(s) used ( via eBay for instance ), the explanation of their poor performance might be more easily explained.

You wouldn't be the first to be burned this way.

:)

Earl, Yes, indeed, I bought them used on eBay, and that, I guess, serves me right! Yet the fellow who's been repairing and reconing speakers (JBLs and TADs) for me for many years can find no malfunction. That's what baffles me.

How do the curves of your drivers compare to those found in this linked thread?

For example;

http://www.audioheritage.org/vbullet...8&d=1470779794

:)

HI again, Earl. I don't have any response curves for the D2430K drivers. I don't think they were tested to that extent. Just got a verbal report that they were functioning normally. Though I also got a report from a different tester that, whether configured as 8 ohms or 32 ohms, the drivers, on the STX825 horn, roll off even more rapidly than the older JBL large format drivers, such as the 2445J. Curiously, I was also told to use a four-conductor speaker cable to connect the negative side of the cable to both negative terminals and the positive side to both positive terminals. Which is not how the drivers came to me with that yellow jumper cable between one positive and one negative terminal. In any case, that's why I have abandoned the D2430K and have decided to go with the older 2450SL. . .

Hi dubkarma,

I have no idea who tested the 2430k drivers for you but they are either both faulty or the measurement is wrong. I have done many measurement of many drivers on that horn and there is no problem with the D2's. All drivers will experience a fall off in frequency from about 2-4kHz with about 3-6 db per octave on a CD horn/waveguide , that is normal. So, you will need some type of correction circuit, either passive or active. However, that is not specific to the D2's and it sounds like you get good result on the same waveguide with other drivers.

The info that older drivers have less of a roll off seem to be completely wrong as the 2445/46 are a 2" driver and the STX horn is designed for 1,5" drivers. None of the 2" drivers have the same HF extension as the 1,5 drivers.

On the D2, they should not be configured in any other setup than the two voice coils in series. I think someone screwed up the connection on your drivers. There should be a short lead between the upper (exit facing up) voice coil negative (lower connector) to the lower voice coil positive (upper connector, ie no 3 from to with exit facing upwards). There should be only two leads connected going to the driver with the positive lead going to positive connector on the upper coil and negative connection to the negative connector of the lower coil. Disregard all other info on connections.

Unless the have been subjected to moisture which can destroy any driver I see no reason why both should behave in the same way. I would check the measurement again and make certain that the short connector between the 2 diaphragms are correctly mounted to rule out any phasing problem.

Does both voice coils give on both drivers (4 in total) give correct ohm reading?

The STX horn is quite sturdy so there is no need for extra support unless you are going on the road. I have made many cabinets with that combination and none has failed so far.


Kind regards
//Rob

Will attempt to compare the 2450SL + 2332 horn with the D2430K + STX (#5006812) horn with dual JBL 2235H per channel in 8 cu.ft. boxes tuned to around 30 Hz. Which plan leads to more questions. . .

1. What length bolts are people using to mount the D2430K to the STX horn? 1.25" seem to be too short and 1.5" too long. As you can see, in terms of DIY skills, I stand at a very primitive level.

2. Can one cross over the STX horn as low as 1 kHz? Or even lower? I'm guessing not, based on nothing more than its size. And the fact that JBL uses a 1.3 kHz crossover frequency in the STX825 speaker system, but I don't know what slope is used. If 1.3 kHz is the lowest recommended frequency for crossing over the STX825 horn, the 2235H are definitely not a good match and one would have to introduce a mid-range driver (e.g., 2118, 2123, etc.) or, to remain a two-way design, some other kind of woofer. Prefer to stay two-way and keep the VLF performance of the 2235s.

3. Given that my dual 2235H are in smaller than optimum cabinets (8 rather than 10 cf), so far, using the JBL M553 with its built-in EQ for CD horns to cross over at 1 kHz (fixed 24 dB/oct. L-R slopes) to the 2450SL/2332 yields pretty good results. And that's even before setting up the mike and starting objective measurements and associated tweaking. It's quite possible, for example, that 24 dB L-R are not the right topology to use.

4. For this reason, it would be useful to know whether there are any "presets", perhaps taken from the DMS-1 active system, that could be programmed into the DriveRack 4800 to optimize at least the HF section that uses the 2450SL/2332? I believe I've had enough practice with the dual 2235s that I could, with local help, handle the low-pass section.

5. Which leads (somehow) to a question about using dual woofers per channel. JBL recommends putting two 2235H per channel into a 10 cf cabinet subdivided into two independent 5 cf sub-enclosures, each tuned to 30 Hz. On the other hand, in other of the company's designs (admittedly mostly for PA work), two identical drivers (e.g., 2226H) are placed in one large box without internal dividers. And when George Augspurger designed a pair of speakers for me, he also specified using dual TAD TL-1601bs in a single 12 cf enclosure. . . So what's the current reigning philosophy on enclosures for dual woofers?

Many thanks, guys, for so freely sharing your experience and expertise!

So far, the 2450SL on the 2332 horn gives a more spacious, relaxed presentation (there's some precise engineering terms!) than the D2430K on the STX825 horn. Both crossed over @ 1 kHz with a 24 dB/oct. Linkwitz-Riley slope using the JBL M553 crossover with the CD horn equalization engaged—which is all I have on hand right now.

Perhaps the D2 + STX825 horn doesn't need the –4 dB @ 2 kHz and +6 dB @ 20 kHz that this EQ circuit imposes and trying them without will be necessary. Certainly the 2450SL/2332 benefit from it.

Anyway, shall go ahead and build 5 cf cabinets for the JBL 2234H with 2450SL/2332. And after that for the D2 driver/STX825 horn with the JBL 2216nd-1 LF driver. I anticipate spending much time thereafter getting the crossovers right, probably using the DriveRack 4800 that I've just had refurbished. . .will endeavor to post measurements using the REW calibrated mike and software to which I've recently been introduced. Thanks again, gentlemen, for your many helpful comments!

Quote:

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Originally Posted by dubkarma

So far, the 2450SL on the 2332 horn gives a more spacious, relaxed presentation (there's some precise engineering terms!) than the D2430K on the STX825 horn. Both crossed over @ 1 kHz with a 24 dB/oct. Linkwitz-Riley slope using the JBL M553 crossover with the CD horn equalization engaged—which is all I have on hand right now.

Perhaps the D2 + STX825 horn doesn't need the –4 dB @ 2 kHz and +6 dB @ 20 kHz that this EQ circuit imposes and trying them without will be necessary. Certainly the 2450SL/2332 benefit from it.

Anyway, shall go ahead and build 5 cf cabinets for the JBL 2234H with 2450SL/2332. And after that for the D2 driver/STX825 horn with the JBL 2216nd-1 LF driver. I anticipate spending much time thereafter getting the crossovers right, probably using the DriveRack 4800 that I've just had refurbished. . .will endeavor to post measurements using the REW calibrated mike and software to which I've recently been introduced. Thanks again, gentlemen, for your many helpful comments!

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Hi,

It has been shown that some improvements can be get using Jbl 2452 and STX825 by applying 0.5 inch "spacer" between them. A kind of notch in the response can be almost eliminated.....so may be with 2450-1.5 the same results can be get if necessary.

regards
ivica

ivica, Thanks for the suggestion. However, I'm not using the 2450SL with the STX825 horn; that's for the D2430K. With the 2450SL, I'm using the 2332, which I understand is the same horn and driver pairing (except for the ribbed diaphragm) used in the DMS-1.

Quote:

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Originally Posted by ivica

Hi,

It has been shown that some improvements can be get using Jbl 2452 and STX825 by applying 0.5 inch "spacer" between them. A kind of notch in the response can be almost eliminated.....so may be with 2450-1.5 the same results can be get if necessary.

regards
ivica

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Where I can find this report? I could only find opposite report adding a spacer...

http://www.audioheritage.org/vbullet...PT-F95HF/page4

In my adapter drawing the thickness of the adapter is alittle less that 1mm which seem to work fine. Originally I had a thicker platebut that was not as good when measured with 2451/475Nd drivers. A 6-10mmdistance was clearly measurable as an un-even curve.