An experiment gone awry - Learn from my mistakes

[rnathans00]

I have a classic set of Allison Model One's which I've had since 1979. (A new pair of Allison Two's, purchased in 1978 were stolen in transit to my new place in Washington, and these were the replacements.) In the late 1990s I replaced all four woofers with replacements from Allison in Kentucky, but always thought they were a little "bassier" than the originals. Reading much later about the "new" versions of the Allison series, I learned they were some 3 db more efficient. I started thinking, "Perhaps I got woofers intended for the *new* Allison One, and that's why they were putting out more bass. It was just a theory however.

After recently fixing the crossover of a recently acquired pair of CD-6 cubes, I felt bold enough to test that theory, but foolishly without checking with others who might have known better. I decided to disconnect one of the two woofers in each speaker. BAD IDEA, for two reasons.

First, not having the schematics I didn't realize that disconnecting one woofer disconnected the second one as well.

That was bad enough, but in reinstalling one of the woofers (heavy suckers!), it slipped and a section of the foam surround tore. (It's ve-e-ery delicate!) So in the process of testing a faulty theory I damaged an otherwise perfect driver. I can't "hear" the damage, but when the time comes to sell the Allison One's I'll have to disclose the flaw - or have them fixed and chance damaging the driver again when I reinstall it.

[JKent]

If the foam surround is that delicate, it's probably shot (as are the other 3). Suggest you contact M_Sound for a double refoam kit and redo them.

Kent

[thechatterboxman]

I am no expert, but I agree that the foam surround should not have crumbled so easily if it was still good. I had a pair of Infinity RSIII-B's for a number of years. We lived in an old VA house with no AC. The humid summers there accelerated the deterioration of the foam surrounds on the four 10-inch woofers in those speakers.

Some years after I bought the speakers, I played a particularly bass-heavy passage at a high volume level. One of the surrounds tore. I was amazed at how the surround crumbled when I touched it. I ran my finger around the other three surrounds, and they simply fell away from the plastic cones which were supposed to be "good for a lifetime," (Salesman.) I believe the speakers were about 7 years old when this happened. I paid $200 to have all four woofers refoamed and sold the speakers...for $300. I have never bought speakers with foam surrounds since. It is just a personal prejudice I have.

Randy

[mpfrank]

Definitely refoam all the woofers - they are way overdue. Either get them professionally done, or do it yourself (I have done many). Make sure to get surrounds that have angled inner edges. The ones sold by Audiodogs on Ebay are good.

All your "mistake" did was alert you to this inevitable situation, so no need to feel bad.

[newandold]

On ‎3‎/‎19‎/‎2012 at 11:51 AM, rnathans00 said:

I have a classic set of Allison Model One's which I've had since 1979. (A new pair of Allison Two's, purchased in 1978 were stolen in transit to my new place in Washington, and these were the replacements.) In the late 1990s I replaced all four woofers with replacements from Allison in Kentucky, but always thought they were a little "bassier" than the originals. Reading much later about the "new" versions of the Allison series, I learned they were some 3 db more efficient. I started thinking, "Perhaps I got woofers intended for the *new* Allison One, and that's why they were putting out more bass. It was just a theory however.

After recently fixing the crossover of a recently acquired pair of CD-6 cubes, I felt bold enough to test that theory, but foolishly without checking with others who might have known better. I decided to disconnect one of the two woofers in each speaker. BAD IDEA, for two reasons.

First, not having the schematics I didn't realize that disconnecting one woofer disconnected the second one as well.

That was bad enough, but in reinstalling one of the woofers (heavy suckers!), it slipped and a section of the foam surround tore. (It's ve-e-ery delicate!) So in the process of testing a faulty theory I damaged an otherwise perfect driver. I can't "hear" the damage, but when the time comes to sell the Allison One's I'll have to disclose the flaw - or have them fixed and chance damaging the driver again when I reinstall it.

I still have one unused woofer that was used in the last, newest version of the Allison One from 2001.

When I get back to my pc, I will post pictures of all the A1 woofers I've dealt with since 1976.

That "new" woofer worked fine in David Faulkners last A1 incarnation as a set of four, but were an ill fit for the original cabinets.

 Those A2's stolen had 16ohm woofers wired in parallel, so on those your experiment would have worked.

Bill

[newandold]

From top to bottom:

1980's

Second Photo around 1994

Last photo 2000, note the wide dust cap....these are the woofers that were in the last version of the loudspeaker, It's been said, supplied by the last owner, but built by Eminence.

 

Bill

[newandold]

I realized yesterday you (and I) were responding to a post from 4 and one half years ago!

Let's hope the problem was solved by now.

 

Bill (chronologically challenged)