" wrote:
On Monday, June 9, 2014 7:21:13 AM UTC-7, dave wrote:

I have some AR4x that appear to
have the original surrounds from ca 1968. All foam not created
equal. Refoaming is not difficult.
Are yours really foam? I have some AR-2ax's from the early 1907s, and
the surrounds appear to be rubberized cloth (which should make a better
seal than foam). They have survived over 30 years of California smog
with no obvious degradation. I do not remember seeing foam on any of the
old AR speakers (AR 1-4) I have seen at the swap meets.

Its not foam or rubber. It's treated cloth. Some kind of substance. I've
seen the treatment seep down, but the stuff might be different on different
drivers.

Greg