Axiom Home Page Forums General Discussion Technical Questions Measuring Speaker Cones.....

Stop Robin my thunder.

Oh, Jeeeeez, here we go......

Everyone hold on!

I was hoping that Alan will drop by sometime and contribute his knowledge to this thread and answer Mark's original question. I am not as hopeful anymore but certainly enjoying the wise cracks. Perhaps Alan is as well.

I am surprised that a standard similar to measuring tires does not exist for speaker drivers.

John

Warning:
I tried to help out by measuring my wifes cones.

let's just say that didn't work out very well for me.

Hi Mark,

Generally when driver sizes are specified, you use the purple line, so the diameter includes the foam surround, as KCarlile and others have already noted.

Sometimes I've noticed that manufacturers interpret driver dimensions rather broadly and include the widest possible dimension to the outer edges of the basket.

While it may be fun to buy kits to add new surrounds to drivers whose foam surrounds have deteriorated, don't expect the speakers to perform anywhere close to their previous standards. The elasticity/damping of a driver surround is carefully specified during its design and re-foaming can never hope to duplicate those standards.

It's certainly OK to get an old pair of speakers working again, but in my view, nostalgic memories of cherished old speakers should remain that way. Besides, I've found that when you drag a pair of those much beloved old speakers out of the closet (I have a fair number of them) and put them into a controlled double-blind A/B comparison with really excellent modern speakers like Axioms, many of the old speakers sound truly awfu and very colored. It's astonishing the progress in speaker design and fidelity that have taken place since the 1960s and '70s.

Regards,

Alan

My brother restored jukeboxes and found that there's a thriving business there re-coning old jukebox speakers (and refurbing their amps).


Alan -- any thoughts on how long foam surrounds are good for? Ballpark 10 years? 15?

Hi Anthony11,

Re-coning old speakers for jukeboxes and the like is fine.

The type of foam surround that a lot of manufacturers back in the 1980s, including Axiom, began to use seemed to last about 10 or 15 years, but it also was influenced by the climate and humidity. A competitor of Axioms who shall remain nameless introduced a very large subwoofer that used a 15-inch driver and discovered that purchasers of the product who lived in the Caribbean found that the foam surrounds disintegrated after a year or so of use.

Nowadays, virtually all quality manufacturers use a rubber composite or butyl type rubber that should last many decades.

Regards,
Alan

Yep, it was kind of scary seeing how non-precision those things were, and of course they're not anywhere near linear.

Now, if I could only find someone who could fix my SMC-1

Glad to hear that modern surrounds have an increased lifetime -- that may help with the ever-popular WAF in justifying my Axiom purchase.

I'll certainly agree with that statement. My first speakers were a pair of Advents, considered one of the best value priced speakers of the time. In todays $ they fall between the M22 and the M60, probably closer to the 60. I am willing to bet that the M22 far outperforms those old Advents.

Wonderfully illuminating as usual, Alan. Thank you very much for sharing your thoughts.

john