AirFlex 5100

[Fitts]

I have some Altec reconing instructions that call for AirFlex 5100 to be applied to the accordian part of the cone. It seems this is the shiny, black, tacky stuff that can be found on most Altec woofers.

Can anyone please share with me what they know about this product. What does this stuff do for the speaker? How much and in what way does applying this product modify the T/S parameters? Does it make the woofer last longer? And lastly, where can one get this stuff?

Thanks,

[Charles Chance]

Airflex is made by Air Products but don't know if they still make the 5100. Their website is Air Products

[Fitts]

Thanks, I'll contact them and see if this is still available.

Any idea as to what effect this stuff has on the T/S parameters of a spearer if any ?

[gearjammer]

Hi That edge damping dope is really clear it just looks black when it is laying on the the surround.

[Fitts]

Thanks for that bit of info, it will make my searching more productive.

[GM]

Hmm, did they change it in recent times? All my OEM drivers, as well as my factory authorized recones (all prior to '72), are doped with a caramel colored chemical.

GM

[Charles Chance]

They may have. All my pre-1970 416A's have the clear(appears black) application - very sticky, all the cat hair and dust sticks to it well.

[gearjammer]

From what i have observed when using the clear dope that i have it enhances the color of the surround material that it is applied to.

[AllanCT]

Here is something I cut and pasted from an audio glossary on speakers.

Some of it is even true.

"Description: The surround is that area out at the periphery of the cone and usually has from one to three corrugations. Its main purpose is to connect the cone to the rigid basket while allowing the cone to vibrate freely. It also serves to terminate or dissipate the waves or vibrations that travel up the cone towards its periphery. It has its own resonant frequency and can have an effect on the overall frequency response by putting a notch or peak in the response at certain frequencies. The resonating surround can also impart energy back into the cone, producing an audible signal that is often referred to as edge yowl. Since the cone is at its thinnest at the surround, and in the case of a cloth surround, very pourous, it is easy for low frequencies to leak through the surround from the rear to the front and cause some cancellations. This is particularly true in a closed back cabinet where pressure builds up. For this reason, some cones are doped or sealed at the surround. Some manufacturers dope the surround to suppress the surround resonances, thereby reducing the effect of the resonances (or anti-resonances) on the response of the speaker. A third reason is to strengthen and protect the surround from effects of constant flexing, temperature, humidity, etc. Since the doping reduces the texture and complexity of the sound from the speaker, many guitar players prefer undoped cones."

#3 is especially important for speaker longevity.

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I have read more than once that (suitably thinned) rubber cement (the kind for sticking paper together, not tire patches) is a suitable substitute for Altec's surround dope. Has anyone contacted GPA for information?