Who has done this ?........ ( Older ALTEC Woofers )

**bowtie427ss** · January 15th, 2014, 09:14 AM

BTW it only holds individual drops, as the water wants to cling together. As soon as the weight of the water exceeds the resistance provided by the screen, it comes right thru.

Surface tension!

I notice a persistent theme in this thread that suggests or implies that Altec used only one type or formula of surround dope. This should be addressed and corrected.

GM, where are you? Your ongoing absence is becoming worrisome. Hope all is well.

**604man** · January 15th, 2014, 04:19 PM

I don't think Altec would send out a woofer with this sloppy dope on the surround. interesting
data.......GC

Hasling Audio Systems Denmark Look under "Altec" "How I came to renovate Altec bass drivers"

**LowOhms** · January 15th, 2014, 06:41 PM

Originally Posted by 604man

I don't think Altec would send out a woofer with this sloppy dope on the surround. interesting
data.......GC

Hasling Audio Systems Denmark Look under "Altec" "How I came to renovate Altec bass drivers"

I agree, the clumping of goop at the bottom occurs in HOT environments, when the "goop" migrates, over time from top to bottom, along the path of the accordion surround. A very small percentage of old-time ALTEC users used to turn their woofers 90 or 180 degrees every two years, on the baffle board, to avoid this from happening.

Jeff Medwin

**604man** · January 15th, 2014, 08:00 PM

I lived in a hot enviroment with my 604-8G's and never had this problem ......A sloppy job

applying dope to the surround. Must be A non Altec / DIY re-cone job....Fortunately,

Easily repaired.

Jeff, how much of the dope did you remove ? Is the surround still shiny ?????

Do you have pictures ????.....GC

**mah** · January 15th, 2014, 09:01 PM

Replay, some dope on goop: http://www.hostboard.com/forums/f700...dope-here.html

**wws944** · January 15th, 2014, 09:13 PM

In the patent description for the Biflex cones (Patent US2834424 - Sound-reproducing device - Google Patents), they discuss the "viscous damping liquid" used at the junction of the inner and outer cone portions: "Solutions of plasticized cellulose nitrate having suitable sound-damping qualities are sold under the trade-mark Viscoloid by the Radio Corporation of America or as 54007 Cement by the Du Pont de Nemours Corporation."

Looking at my new-to-me 420A Biflex drivers, it looks like the same stuff was used both between the inner/outer cone portions, and also on the cloth surround. Granted the above patent was discussing the 415A, which had a paper surround. So I guess it is possible they used a different liquid in the newer drivers.

**zelgall** · January 15th, 2014, 11:28 PM

Jeff, I have a number of Altec bass speakers including 416s, 420s and 421s and I'm not one hundred percent sure that the dope is even opaque. I believe it's a translucent material when applied. If you hold a 416 up to a light, you can see through the surround.
The cloth surrounds definitely need to be sealed to function correctly and that's not just an opinion. The box would be aperiodic if the surround allowed air to pass through or it would add to the vent area.

**Altec Best** · January 16th, 2014, 01:23 AM

Here's another thread on the surround dope.

"http://www.hostboard.com/forums/f700...ound-goop.html"

**tomt** · January 17th, 2014, 02:48 AM

so now we have the dope about the goop ...

**cradeldorf** · January 17th, 2014, 03:42 AM

Originally Posted by zelgall

The cloth surrounds definitely need to be sealed to function correctly and that's not just an opinion. The box would be aperiodic if the surround allowed air to pass through or it would add to the vent area.

That was my first thought when I started reading this thread, with the pores of the cloth wide open it was gonna leak like a sieve. cancellation to the max.