12" woofers

[Triumph Don]

Can anyone describe the sonic difference between the 122, 123, and 128 series 12" woofers? Still working on my low DB bedroom system. McIntosh 754 amp, 113 preamp tuner. Thanks!

[Robh3606]

Hello

Well the 123 is alnico with a curvilinear cone a couple of versions D123 fullrange with an aluminum dust cap and the famous white woofer in the L100 123. The 122 has a larger magnet also alnico was used in the L166 Horizon and the A version of the L65 Jubal, Two versions one with and a mass ring one without. The 128 is a Ferrite woofer used in the L112 Century 2 and in various versions in the 4412 and TI series 120Ti.

Sonic well the 123a will tune with a hump in the 40-70hz range in a 2-3 ft cabinet but was used wide open in the 4311/L100 so its rool of is smooth. The 122 will tune up flat and has a more extended lowend than the 123. Sounds fine to me. The 128H-1 that I have is very smooth and just a nice sounding driver. Lower distortion by virtue of its SFG motor.

Rob

[speakerdave]

I can confirm the remarks about the D123, 123A and the 122A. I'm not familiar with the 128. The D123 has a nice sound but should have about a 3.5 ft cabinet and should be crossed over at 3500 or below. You can match it with the LE20 tweeter using the LX2 crossover. Good pairs go on eBay for between $150 and $200. I have two pairs that are available, one considerably cheaper than that, if you want to send me a PM.

The 123A was made in two versions, 123A-1 and the 124A-3. The only difference between them that I am aware of is the frames. These will make a punchy sound in a small enclosure. The D123, I believe, is no longer supported by JBL. The 123A can be reconed, but very expensive. None of these have foam surrounds.

The 122A has a foam surround and most on the market will be candidates or will already have been done--competently or not. This woofer is similar in some ways to the 124A--the same free air resonance of 17 Hz--but it has a smaller motor and a three inch voice coil not the four inch. I have this woofer in my L65As and now that the new foam has relaxed it's a decent woofer in a 2ft box. The 122A price on eBay is unpredictable, but I've seen them go for over $200 a pair.

The 124A/2203 is a rare and wonderful beast, and I think the 2203H, the ferrite version, is almost as hard to come by. Both have foam surrounds and I believe the cone kit is no longer available.

I don't know what your budget is, but the 12 inch woofer used in the LSR 32, the 252G, is available new for about $235 each. It's a "modern combination" dual voice coil with an additional brake coil, rubber surround--no foam-- and neodymium magnet and is far superior to the above mentioned woofers.

Have fun,

David

[Guido]

Originally posted by speakerdave
I don't know what your budget is, but the 12 inch woofer used in the LSR 32, the 252G, is available new for about $235 each. It's a "modern combination" dual voice coil with an additional brake coil, rubber surround--no foam-- and neodymium magnet and is far superior to the above mentioned woofers.
David

I always wanted to ask this

How can one handle these double voice coil in a stereo system? How do the T/S values differ if only one coil is in use?

What is a break coil?

Thanks!

[4313B]

http://www.jblpro.com/pub/technote/tn_v3n02.pdf

[Triumph Don]

Thanks for your input! I just added a pair of refoamed 122 A's to my inventory. Remember, this is for a low DB system in a small room. How will these sound replacing the 123's in an L100 cabinet with original crossovers? Should I just try to find a non existant pair of Jubals?

[4313B]

Originally posted by speakerdave
The 124A/2203 is a rare and wonderful beast, and I think the 2203H, the ferrite version, is almost as hard to come by. Both have foam surrounds and I believe the cone kit is no longer available.

Well, this is true. It seems JBL has given up on yet another transducer. The 124A/124H/2203A/2203H kit is NLA "forever". However, all is not lost. There is presently a workaround so if you need any of theses drivers serviced send me a PM