12" woofer in C34 or C40 cabinets?

[Nordschleife]

Has anyone tried a 12" JBL driver in a C34 or C40 cabinet?

I recently added a B380 JBL subwoofer to my system. That change made a significant improvement below 70z or so. But at higher volumes it also pointed out the standard 130a woofer's struggle to keep up, especially with the mid-bass line (80 - 1200z) in rock music.

I was wondering if I should try substituting a mid-bass driver in a smaller cone size like 12" or 10". Maybe a 2202A, 2206H or HPL or 123a? Something that crosses over well between the 175 mid-tweeters @1200 hz and the B380 at 80z on the bottom.

Thanks,
Andy

[speakerdave]

Keep up? Could you be more specific? I would be surprised if the 130a is not loud enough. Do you need to turn down your horns? If you mean that at high spl you begin to hear the distortion in that driver, I would have to agree, much as I like other things about it.

The 2206 would cover that range, but not sure how it would work in that cabinet.

[RMC]

The C 34 is the ancestor of the 4530 cabinet. That should give you a hint on the preferred more recent drivers for that box: 2205H, E-140, and to a lesser extent, the 2225H. You may find a 2205 reconed to 2225 also.

I agree with speakerdave that a 12" driver may not be proper for such cabinet. I remember reading many years ago a tech article (can't remember where) mentioning that a 12" driver would not work properly in that type of box because of throat and/or mouth dimension issues if my memory is correct. That was in response to a frequent question re scaling down the 4530 cabinet size and using a 12" driver instead. I think the reply was from a JBL Engineer. I guess JBL would have offered that smaller version if it would fly, but they never did...

Richard

[Nordschleife]

Thank you SpeakerDave & Richard. I appreciate your replies.

Dave, when I said "keep up", I meant that on complex bass passages in rock music, the 130a seems to struggle to articulate the electric bass when the volume is raised to high levels. The 175 (and the 075) drivers are wonderfully detailed and the 2235 in the B380 is able to keep up too.

Maybe I'm imagining it, but the 130a's seems to get a bit harsh and lack detail at higher volume. So I wondered if a smaller JBL woofer of less mass (but high efficiency) might work & move air better?

I may give it a try regardless.

[RMC]

So I wondered if a smaller JBL woofer of less mass (but high efficiency) might work & move air better?

You may want to try first, in that rear-loaded folded horn cabinet, a 2220 15" driver which has a lighter cone than most other JBL 15" low frequency drivers. Though the 2220 was never recommended for that use, it does have very high efficiency, and its T/S parameters (Fs, Qts, Vas) ARE compatible for such use, but it has limited Xmax 2-3 mm (depending on version), and supposing you can put up with its pretty high mid-bass rising response... Most probably you won't get earth rattling high level low bass from that driver however...

Richard

[speakerdave]

When you say "high levels" I wonder if you are over-driving that woofer. How much power are you putting into them? That cabinet and that driver were developed when 15 watts was considered enough, 30 possibly overkill and 60 wretched excess. If you have the original cone and you have been hitting it hard there's a good chance you have over-stressed the integral paper surround and weakened or even separated it in places; that is especially likely if you drove it too hard at frequencies below the horn cutoff before you got the subwoofer. The 2225 will take that kind of abuse. The 2220 is in fact a later pro version of the 130a and has a strengthened surround and a higher temp voice coil former; that may be more durable but still may not be the right driver for what you require. There are Alnico versions, if that is your desire. It is a little difficult to find clean ones, I've found. The 2227 would be ideal but is out of production and quite rare. The 2226 is still being made and there may be new neodymium drivers that will work, though you may not be planning on getting hundreds of $ worth of woofers.

I have some some very clean 2225H I need to get rid of, but they are heavy and we are on opposite ends of the country. I don't want to give them away, either.

[Horn Fanatic]

Has anyone tried a 12" JBL driver in a C34 or C40 cabinet?

I recently added a B380 JBL subwoofer to my system. That change made a significant improvement below 70z or so. But at higher volumes it also pointed out the standard 130a woofer's struggle to keep up, especially with the mid-bass line (80 - 1200z) in rock music.

I was wondering if I should try substituting a mid-bass driver in a smaller cone size like 12" or 10". Maybe a 2202A, 2206H or HPL or 123a? Something that crosses over well between the 175 mid-tweeters @1200 hz and the B380 at 80z on the bottom.

Thanks,
Andy

Greetings - Neither the 2202 or 2206 are the best candidates for horn loading. And especially the 123A. The 130A or 2220A are the best choice for the C34 and C40. There was a version of C40 that was loaded with I think a D123, but that driver is not horn worthy either. The 2220A shares the exact Thiele-Small parameters as the 130A.

Keep in mind, as the 130A was used in HiFi systems, it was not designed for high power levels. Nor was the C34 designed for sound reinforcement. I sincerely believe you would be disappointed in the performance of loading a C34 with a 2205, 2225, any 140 series driver, and especially the 2226. The primary issue is the chamber volume of the C34 is much to small to acoustically load those speakers properly. The chamber volume and throat area for a rear loaded horn behave as an acoustical low-pass filter. They're parameters are inter-related, and as such critical to the performance of the horn. I may suggest the E130 as a replacement. Or at the least, the D130. Not the D130F. And definitely not the K130.

If you're having problems with your 130A's, perhaps re-gaussing would be in order. After all, they are well over 50 years old.

There is only one 12" speaker I would recommend for horn loading. The Beyma 12E120. It will operate admirably in a small volume, but the C34 throat area may be too large. speakerdave suggested a neo driver, but the speaker may not physically fit in the C34 or C40 chamber.


IMHO - The 150-4C would be the ideal speaker to load into the C34. If you could find real ones. There are more counterfeit 150's on Ebay than you can shake a stick at.
A customer of mine bought a pair on Ebay from that clown in Stanton California who is known for counterfeiting 150's and 375 Bubble Backs. I conducted T-S testing on them. The results were shocking. Among other disturbing anomalies, they had a free air resonance of 80 cycles. Yuk!

Good luck, H.F.

[RMC]

The 130A or 2220A are the best choice for the C34

Hi Horn Fanatic,

Thanks for the clear explanation of yours on the tech issues here. Wouldn't the 2220H more recent version of 2220 also be a very good fit, if not best fit? I re-checked its T/S in the data sheet and to me they look quite good for this... In addition to higher power capacity, that H version has 3 mm Xmax, a little better than the 2220A's 2 mm, in case our NH friend wants to beat on it a bit in the bass range... Regards,

Richard

[Horn Fanatic]

Hi Horn Fanatic,

Thanks for the clear explanation of yours on the tech issues here. Wouldn't the 2220H more recent version of 2220 also be a very good fit, if not best fit? I re-checked its T/S in the data sheet and to me they look quite good for this... In addition to higher power capacity, that H version has 3 mm Xmax, a little better than the 2220A's 2 mm, in case our NH friend wants to beat on it a bit in the bass range... Regards,

Richard

Hello again, RMC -

The 2220H has slightly different T-S parameters than the 2220A. Not enough to be noticeable. he 2220H may be an easier driver to find used. I would be leery of after market re-cones. To my knowledge, no after market supplier has ever proven their cones are exact replacements. Just because it fits, does not mean it is an exact replacement.

Take the 150-4C's I mentioned earlier. I thought perhaps the cone kits were E145 kits. The results of the T-S- testing revealed parameters of which I have never seen before on any kind of woofer. Absolutely none of the parameters I tested came even close to an E145, K145, or any JBL woofer.

Regards, H.F.

[Nordschleife]

I would love to use 150-4c's... but the expense is beyond me, I think.

Given the insights (thank you!) by forum members in this thread, I think my best option would be either the JBL 2227 or the Beyma 12E120. But after searching online for over an hour last night I could find neither of these drivers available anywhere, used or new condition. Does anyone have a possible USA source for the 2227 or this model Beyma?

By the way, the C34s & B380 speakers are being driven by an Audio Research D76 tube amp (quad of 6550 tubes @65w/channel). Preamp is Ampex model 018 pre/tuner, also tube. And yes, I do like to turn them up sometimes.

[speakerdave]

The 2220 would be a good fall back option with that amp. Be sure to get original cones.

[Earl K]

​

I would love to use 150-4c's... but the expense is beyond me, I think.

Given the insights (thank you!) by forum members in this thread, I think my best option would be either the JBL 2227 or the Beyma 12E120. But after searching online for over an hour last night I could find neither of these drivers available anywhere, used or new condition. Does anyone have a possible USA source for the 2227 or this model Beyma?

By the way, the C34s & B380 speakers are being driven by an Audio Research D76 tube amp (quad of 6550 tubes @65w/channel). Preamp is Ampex model 018 pre/tuner, also tube. And yes, I do like to turn them up sometimes.

Are you running those C34's and B380's paralleled off of one amp ( ie; loaded down to 4 ohms ) ?

I wouldn't do that ( I'd add a separate amp for just the B380's ).

[Nordschleife]

Earl: my mistake. No, there is another amp. The C34's are driven by the ARC D-76 tube amp. But the B380 subwoofer is driven by an ATI 1502 solid state amp in bridge mode. There is a Paradigm subwoofer crossover box that determines the high pass frequencies. I currently have that set at 65hz for the B380, so the 2235 in the B380 is handling 20-65hz and the 130a's in the C34's are handling >65hz - 1200hz (typical JBL n1200 crossover for a C34).

[Horn Fanatic]

I would love to use 150-4c's... but the expense is beyond me, I think.

Given the insights (thank you!) by forum members in this thread, I think my best option would be either the JBL 2227 or the Beyma 12E120. But after searching online for over an hour last night I could find neither of these drivers available anywhere, used or new condition. Does anyone have a possible USA source for the 2227 or this model Beyma?

By the way, the C34s & B380 speakers are being driven by an Audio Research D76 tube amp (quad of 6550 tubes @65w/channel). Preamp is Ampex model 018 pre/tuner, also tube. And yes, I do like to turn them up sometimes.

The 2227 was taken out of production. Good luck finding a pair. If you chose the 12 inch route, the 12E120 is available through U.S. Speaker. Again, I am certain the throat area of the C34 is too large. I can calculate the chamber volume and throat area for you if you're interested. Modifying the throat area would require some modest wood working skills.

The 12E120 is Beyma's answer to the JBL E120. However, the free air resonance of the 12E120 is around 37 Hz, compared to 60 Hz for the E120. The free air resonance of the 130A / 2220 is also 37 Hz. The mechanical Q for the 12E120 is much greater than the E120, but the Qts and Qes are nearly identical.

H.F.