Nicotine reidue on drivers

Why would you buy speakers from a heavy smoker?

What you have to think about is, can it be possible to stiffen a polypropylene cone just with vapor deposited Beryllium partials on it.
To be honest I don't think so, as the Beryillium particles would have no structural strength in either plane at all, unless it's spun or forged as in the GF-1's then there's no need for a polypropylene former under it.

Cheers George  

I have a set of Yamaha NS 1000m speakers. I really like the sound. Once put on stands at the proper height and set up with a bit of rake and toe they are spooky magical. However found the most perfect amp for them. The Bryston B60 integrated amp. I have had some really big expensive amp/speaker systems and this right up there.  Do not laugh that is the perfect power for NS1000 speakers!

In fact what you observed is what would happen if the Beryllium was vapor deposited onto an untreated or poorly treated polypropylene surface.

It wasn’t a causal light wipe, thinking they were pure Beryllium and nothing else, and could take some cleaning solvents like metho, turps which shouldn’t effect Beryllium.
I wiped lightly what looked to be nicotine stains with dust embedded in it, almost salt air corrosion to look at, on the tops of the mid and tweeter domes. With cotton buds moistened with mentholated spirit, after a few light wipes I could see through the dome where I wiped, being a clear polypropylene dome.
Lucky I had a store back then of a few JA0548A and JA0803 which are the Yamaha part no’s for the mid and tweeter.

Cheers George