In my opinion, far too much ado is made over damping 811's and 511's. Once they're firmly mounted with a good cork or rubber gasket around the front flange using all 6 bolts to positively secure the horn to the baffle, the only portion of the horn left to resonate are the "bell" sections ahead of the mounting flange, and yes they do ring a little if you strike them with a solid object.

It's my understanding, gleaned from posts made here in the past, that the Altec engineers did nothing to damp these horns simply because the small format drivers do not produce enough acoustic energy to "ring" them once they're properly mounted.

I have noticed audible ring from unmounted 511's in a rare and extreme circumstance where i pulled a plug from a power strip causing a significant "pop" to be picked up by the HF amplifier when no other signal was present. The decay on the backside of the pop was heavily colored with the timbre of the 511's resonance, it's the only time i've detected any audible ringing where the driver was the source.

Everyone's mileage seems to vary on this issue, so please take my post with a grain of salt.

But, at the end of the day, don't be afraid to reach your own conclusions. Ultimately, until resale time, you are the only one who need be satisfied by your speakers.

just my .02 y'all understand.......................