Jump to content

Help Restoring Pair of CD 9


Recommended Posts

Hi to all Allison lovers,

I just acquired a pair of CD 9 speakers that need some TLC ! I was hoping I could get some advice as to how to proceed and locating replacement components.

- One tweeter dead

- Original 10" woofers replaced with "vintage" Realistic brand speakers

- Front grills cracked & beat up, need replacements

- Bottom grills missing, need replacements

- Status of crossover unknown, do these need to be rebuilt after a few decades of service ?

Otherwise they sound pretty nice :>)

Is there a recommendation for a good 10" substitute ? Is it possible the "vintage" (I haven't checked the dates) Realistic is a good fit for this speaker ?

There is a Allison tweeter from the Allison Four on ebay for $90 + shipping, which is almost half of what I paid for these. Which models use the same tweeter as the CD 9s ? Does anyone have a source on these at a more reasonable price ?

I was thinking about making speaker covers by devising a plastic or balsa wood frame and cover it with speaker cloth.

Any help would be much appreciated !

All the best,


Link to comment
Share on other sites

Hi Beetlebum and welcome to CSP

You may want to check this thread:


As I understand it, the classic Allison tweeters are interchangeable as long as you use two-way speaker tweeters with two-way speakers and 3-way speaker tweets with 3-way. Unfortunately the Allison site is now defunct.

There is a very active Allison forum on Yahoo and you may get more info there.

If you can use the Audax TW025A2 tweeters I mentioned, I have a pair for sale.


Link to comment
Share on other sites

Kent, thanks for the reply.

How do you tell the difference between a "one way" and "two way" tweeter ?

I've got a bid on one one ebay, that looks just like the ones in the CD 9.

As a curious side note, I had dented midranges (nose cone pushed in), and used my vacuum cleaner hose to gently pull it back into position ! It may be a psychoacoustic effect, but the seem to sound better.



Link to comment
Share on other sites


The CD-9 is a 3-way speaker system: Woofer, midrange, tweeter


The Four is a 2-way system: Woofer & tweeter:


I don't know if the "One Series" (including the Four) used the same tweeters as the CD series. If that tweeter on ePay "looks" right, maybe ask the seller if there are any markings on the back and see if they correspond to markings on your tweeter.

If you want the pair of Audax tweets, brand new, still in original boxes, I'll sell them for $50/pr with free shipping in USA:


Folks on the Yahoo Allison thread said this was a good replacement for the Four tweet, but I never installed them.

Check this Madisound page. They recommend the SEAS Prestige 27TDFC for the CD-9, but they are $42 each and should be installed in pairs


I thought I read on one of the forums about a guy making new grilles for Allisons, but can't seem to find it now. However, you can repair yours with "Plas-T-Pair" and black Evercoat if they are mostly intact.


Link to comment
Share on other sites

Kent, that's very helpful, thanks.

Looking at the Allison Driver Specs document from another post, it seems the two-way tweeters have to go down to 2 kHz, and so seem to require a more aggressive cooling solution in the form of the ferro-fluid damping/cooling material. The three-way tweeters bottom is 4 khz, and can apparently get by with the Silicon damping/cooling material.

The specs are otherwise identical, except the 3-way tweeters are rated at 20W continuous power. I'm wondering if they are the same tweeter with different damping/cooling solutions, and different crossovers which result in the different range spec. It is possible that the 2 way tweeter will work in the 3-way configuration as well, given the more limited frequency range it is exposed to. By the same logic, the 3-way would NOT work in the 2-way speaker.

I'll have to get down to business and check the serial numbers, ect to see exactly what I'm getting.

Thanks for the offer on your tweeters, I'd like to put original Allison back in if I can.



Link to comment
Share on other sites

Thanks for the offer on your tweeters, I'd like to put original Allison back in if I can.

I understand. Of course, you also have the Rat Shack woofers to contend with. They "may" be OK--especially if they are well constructed and have big alnico magnets. Take a look and maybe post photos. Probably the surrounds rotted and the previous owner put in new woofers instead of refoaming the originals. I would bet that a pair of good New England woofers would be good replacements--as long as they were 4 ohms and a good physical fit (others may disagree). KLH Model Twenty, for example, is an excellent 4 ohm 10" woofer with cloth surround, and they usually sell for a low price. You'd just have to check the exact diameter and compare to your cut-out since not all "ten inch" woofers have the same outer diameter. Original Allisons would be the best choice but may be harder to find. Some members have found a (Parts Express) Dayton woofer that works well with classic NE speakers but I'm not sure which model it was.

As for the xo, I did not do anything with my Allison: Fours and they worked fine. OTOH, I did replace the electrolytic caps in a pair of RA Labs (Allison) speakers with polys. Replacing old electrolytics couldn't hurt ;)

For your bottom grilles, something like this may work:



Link to comment
Share on other sites

Here's a potential replacement for the missing CD9 10".

It appears to meet spec on impedance, power, sensitivity, response, but not on Fs (45Hz instead of 25Hz).

Is it too deep at 4 3/8"?

What do you guys think, close enough ?


10" Replacement Speaker Woofer Part # W-10PC-4

Aluminum Frame

Poly Mica Cone, Rubber Surround, Gold Binding Posts, Vented, Bumped Backplate

Size: 10-1/4"

Hole cut-out: 9-1/8"

Depth: 4-3/8"

Voice Coil: 1-1/2"

Magnet: 40 oz

Impedance: 4 ohms, Re: 3.8 ohms

Power: 200 watts RMS, 400 watts max

Response: 25-3000 Hz

Sensitivity: 93 dB, 1 watt, 1 meter

Le: 1.4 mH, Fs: 45 Hz, Vas: 1.12 cu. ft., Qms: 4.5, Qes: .45, Qts: .40, Xmax: 4mm

Great replacement woofer for many high powered speakers, including Altec, Cerwin Vega, EV, and JBL!

Link to comment
Share on other sites

  • 1 year later...


This topic is now archived and is closed to further replies.

  • Create New...