Quote Originally Posted by Coendert2011 View Post
Hi,

Thanks.
I've no easy way of making and adding a pic. Frams are black lipped frames with '1.4-20-035414' and 'Altec Lansing Corp' cast into the plastic. It looks rather original. The rubber gasket of the rear cover was almost glued. I guess they haven't been open for a long long time, you can almost smell the 80s.

No visible damage on the alu dia either and yes both units have the same issue. They are very identical.
I had the same experienced! However, mine was a 288C with diaphragms similar to the construction that you described (the ridge is somewhat orange on mine) and has the "Altec Lansing Corp" cast into the plastic as well.

I also tried the 511 for it for a few months with N501 XO, 1st order 500 hz, 1st order 800 hz, 2nd order Linkwitz 500 hz, and 1st order 900 Hz without sucess as the sound is nothing to be proud of (using 416 as LF on 612C cabs). On a whim, I bought the cheap 8-Ohm 288C diaphragms from an online vendor (in Arizona) for $50 a piece. You can tell that this replacements are cheap but I just want to experiment on it to see if there's a difference. There is, and a lot! In my opinion that "ridge" Altec lansing Corp diaphragms sounds like crap. My plan is to buy a pair of the 288 diaphrams from GPA once and for all when I have the time to play with my sound system again.

FWIW, I also have 802's, and 806's. I tried using them on a Le Cleach 350 horn with an adaptor and they sound very nice. Even on the 811 horns, they sound fantastic of course!

I think it is the diaphragms. But there are lots of factors in one's system to influence an "unwanted" presentation.

Regards,

Abe