Alisson 4 woofer

[bubu91220]

Bonjour, j'ai trouvé des enceintes alisson 4, les woofers ne sont pas d'origine,

Le woofer du modèle 5 ou 6 ,lc110, lc120 convient au modèle 4 ? 

[bubu91220]

this is a picture of the woofer , i think is not good version 

[bubu91220]

This is a woofer Allison ?

[JeffS]

bubu91220,

An original or properly restored Allison:Four woofer will have a foam surround and a textured paper cone that has a sticky coating. The woofer in the picture you provided has a rubber surround and smoother cone with no coating, and is not an original Allison:Four woofer. 

The only proper replacement for this woofer is another Allison:Four woofer, which has an 8 ohm impedance to match up with the series wired pair of tweeters. Woofers from any of the other Allison two-ways (models Five, Six, CD-6, CD-7) are 4 ohm units and are not direct replacements.

I've included a picture of an Allison 8 inch woofer to illustrate what an unrestored unit looks like (usually with lots of dust on the cone!).

 

 

[bubu91220]

Hello jeff , thank you for the information ! i think is not easy to find a woofers for allison 4 , i live in france and the allison 4 are very rare . I'have a allison five speakers with naim system  and i' like this speakers great sound ! 

What is the more musical the model four and the model five ? 

In france is easy to find model lc110 lc120 , the woofer of this model is suitable ? 

[LesE]

The Allison Four woofer is actually 4 ohms impedance.  In the model Four,  there is a 2.2 ohm resistor and an inductor in series with the woofer which raises the impedance to 8 ohms.

Here are the specs for the Allison woofers.   The model Four woofer appears to be unique but the LC110 or LC120 woofer may be a fairly good replacement.   If one could be obtained at a reasonable price,  it may be worth a try.

 

Allison Driver Specifications

[JeffS]

The useful spreadsheet that LesE provides nicely outlines the differences among the Allison woofers. Thanks.

Given the information here, if I were trying to find a replacement for an Allison:Four, the only woofer I would avoid from the two-ways is the Allison:Six which has a voice coil Xmax of 0.1625" compared to the 0.25" of the others. I might also give preference to the LC models, whose woofers would have less potential spider sag than the others.

[newandold]

10 hours ago, JeffS said:

The useful spreadsheet that LesE provides nicely outlines the differences among the Allison woofers. Thanks.

Given the information here, if I were trying to find a replacement for an Allison:Four, the only woofer I would avoid from the two-ways is the Allison:Six which has a voice coil Xmax of 0.1625" compared to the 0.25" of the others. I might also give preference to the LC models, whose woofers would have less potential spider sag than the others.

Could you elaborate on what you mean regarding “spider sag”?

 I have been a bug on Allison spiders within the woofers for years.

I have a lot of experience, going after aging spiders in these drivers. 
For most, the thinking seems to be to just refoam  the speaker and you’re good. 
That’s ok if a driver is perhaps 15 years old or even more.  But if it’s 43 years old, you should think again.

The spider can LOOK fine, but they lose compliance over the years, making it easier to bottom out.

The surround and the spider work together to keep the excursion in check.

[JeffS]

If I were shopping for a replacement woofer for my Allison:Four, and I could choose between woofers that were newer and had been mounted and stored forward facing as in the LC models, or woofers that were older and mounted and stored facing upward with deteriorated surrounds, I'd buy the newer woofer. Having said that, I would give preference to a woofer that came from a Four.

You put a fine point on what I called "spider sag" and we should all use caution when using these older drivers with original spiders.

My experience tells me this: I had a pair of Allison:Sevens that I installed new surrounds on about 15 years ago. They came back to me about 6 months ago for a cabinet refresh. I checked the condition of the surrounds and with them showing no signs of deterioration, I connected them to an amplifier rated at 400W/ch into 4 ohms. I took the volume up. No problems, and they sounded great. Now, I wasn't driving them hard enough to make the clip lights flash, nor would I with any 8" woofer.

10 years ago I put new surrounds on my Allison:Fours. I use them with a 150W/ch amplifier with no problems.

If someone using these Allison 8" models follows the placement recommendations, doesn't add any bass boost, and uses a reasonable amplifier (say, 100-150 W/ch), things should be fine. As you've said in the past, if you want deeper bass while using these speakers, add a subwoofer. 

 

[newandold]

59 minutes ago, JeffS said:

If I were shopping for a replacement woofer for my Allison:Four, and I could choose between woofers that were newer and had been mounted and stored forward facing as in the LC models, or woofers that were older and mounted and stored facing upward with deteriorated surrounds, I'd buy the newer woofer. Having said that, I would give preference to a woofer that came from a Four.

You put a fine point on what I called "spider sag" and we should all use caution when using these older drivers with original spiders.

My experience tells me this: I had a pair of Allison:Sevens that I installed new surrounds on about 15 years ago. They came back to me about 6 months ago for a cabinet refresh. I checked the condition of the surrounds and with them showing no signs of deterioration, I connected them to an amplifier rated at 400W/ch into 4 ohms. I took the volume up. No problems, and they sounded great. Now, I wasn't driving them hard enough to make the clip lights flash, nor would I with any 8" woofer.

10 years ago I put new surrounds on my Allison:Fours. I use them with a 150W/ch amplifier with no problems.

If someone using these Allison 8" models follows the placement recommendations, doesn't add any bass boost, and uses a reasonable amplifier (say, 100-150 W/ch), things should be fine. As you've said in the past, if you want deeper bass while using these speakers, add a subwoofer. 

 

I understand now where you’re coming from regarding the “sag”!

An Allison user on another forum had concerns about the midrange sagging out of alignment (age related). He made a project out of flipping all of his 180 degrees to counteract this. I felt personally, it was a case in point of overthinking a potential issue. ….that with normal use they would be just fine. That being said, nothing lasts forever….

With yours I would think similarly, in that the woofers excursion is upward when operating, so sagging shouldn’t be an issue. Rigidity is something else, where by the spider cloth gets weak with age, the woofer is free to travel farther than it’s design was intended, having only the surround to keep it in check.

[jon heckman]

Just picked up a pair of Allison fours for $5 at a yard sale.   All 4 tweeters are working now that I got two of them reconnected to those nicely engineered connecters.   The drivers sound decent, but they seriously need new foam.  Can or should/need anything be done about dust that is stuck on the drivers?

[newandold]

15 minutes ago, jon heckman said:

Just picked up a pair of Allison fours for $5 at a yard sale.   All 4 tweeters are working now that I got two of them reconnected to those nicely engineered connecters.   The drivers sound decent, but they seriously need new foam.  Can or should/need anything be done about dust that is stuck on the drivers?

Already, you’ve accomplished the most important thing that being 4 tweeters up and running! I wouldn’t lose any sleep over dust on the drivers (you can’t hear that).

Make sure the spiders are well intact and compliant before going ahead with the surrounds on the woofers.

 

Five bucks!? What a deal for a pair of fours can you toss some pictures on here?

[jon heckman]

Thanks for the quick response newwandold.  I have only listened to them on a Danon Surround Sound in stereo mode/tuner.  When I get the time I will hook them up to my Pioneer 780.    I expect them to compare favorably to my Pioneer cs77 speakers.  They also look great, but I really like those classic cs77 grills.  

I have done one foam replacement, successful more or less.   The Allisons look like they might be easier.   I saw a set of 8”foams with glue and instructions listed under “Allison speakers” for $13.   Next in line was twice as much.  If I’m gonna do it I want to choose the better path.  Any suggestions?  Jon

 

[newandold]

1 hour ago, jon heckman said:

Thanks for the quick response newwandold.  I have only listened to them on a Danon Surround Sound in stereo mode/tuner.  When I get the time I will hook them up to my Pioneer 780.    I expect them to compare favorably to my Pioneer cs77 speakers.  They also look great, but I really like those classic cs77 grills.  

I have done one foam replacement, successful more or less.   The Allisons look like they might be easier.   I saw a set of 8”foams with glue and instructions listed under “Allison speakers” for $13.   Next in line was twice as much.  If I’m gonna do it I want to choose the better path.  Any suggestions?  Jon

 

Jon,

Before anything else…… I need to congratulate you! For five bucks those are flat out, the finest looking pair of fours for the money I have ever seen, and I mean ever. as long as you get foam surrounds with the roll radius as close as you can get to what you see on what’s left of the originals you’ll be OK just no rubber that would alter the sonic characteristics that RA built into those systems.

Beyond that I can only tell you that I’m a lightweight when it comes to doing surround work I did it once decades ago and the two words popped into my head never again. I’m pretty handy but there’s certain things that I feel that are best left to the professionals.

The music is simply too important for me to screw around like that.

[newandold]

I have been following the used Allison marketplace on eBay for decades now. Yours are fun to talk about because of what’s MISSING..… And I’m talking about the damage, that is generally present on the pairs on eBay, that dreamers are trying to unload. ……very careworn, the grills are usually damaged beyond repair or missing all together. Those tweeter nipples are almost always dented at the least, or totally mashed in at the worst. Those delicate wires that you managed to reconnect are very often busted, and then they ask all kinds of money for them; all the while I’m trying to keep a straight face . 

[jon heckman]

I recieved the wolfer surround foams from “simply speakers.  If it’s foam, then its foam with a “well on the rubbery side”  feel. 

They don’t fit so well ether!   The highest point of the speaker cone is 1/4 “ bellow the top surface of the speaker frame, and it angles downword from there.  Those corresponding glue points on the new foam are on the some plane.  There is an earlier picture on this thread that clearly shows a speaker with a surround that was made to accommodate the phenomena.    I found that stretching the inside radius of the foam, (foam to cone glue point), would somewhat re-form that surface in the required direction, but not enough.  A bit more stretching and I broke the surround.   

Getting the new foam on might go a bit smoother if I could get the speaker out!   I can’t!   

An earler pic on this thread suggest that the speakers may be made that way?  (y/n)

Can I get surrounds that fit?

Can I make one?  I got some parts on the broken surround that I might be able to glue on the new surrounds.  How touchy are they?   The base sounds reasonable without surrounds.

🤔  Jon

 

 

 

 

 

 

 

[Aadams]

On 5/17/2023 at 10:47 AM, jon heckman said:

Can I make one?  I got some parts on the broken surround that I might be able to glue on the new surrounds.  How touchy are they?   The base sounds reasonable without surrounds.

I have been watching this thread and thought you would have had a response by now. 

You can get the angled inner radius surrounds from Speakerworks https://www.speakerworks.com/8-inchmay-speaker-repair-kit-p/swk8adlx.htm  Call them, tell them what your are working on and they will tell you if it fits.

It is not a good idea to cut and glue surrounds to achieve a fit. 

Your woofer is an acoustic suspension design and therefore relies on the foam surround to help the spider suspend the cone.  Now that the surrounds have rotted away the cone is sagging below the frame which is normal for the type.  In order to get the correct foams installed with the cone at the proper height and insure voice coil centering, the safe method would be to use shims.  The Speakerworks kits come with shims and the correct white glue.  If you are not familiar with how to shim, there are videos on youtube and several threads in the AR speaker forum here at CSP.  You could always send them out to be refoamed.  You might try @Royc.

 

Playing music through those woofers at normal levels without surrounds will damage them.  Allisons were wonderful designs. The AR world benefited greatly from his ideas.  Good luck.