Time for some Horn Damping! The Heath AS-101 have Altec 811-B horns - and metal horns are legendary for ringing.
I hadn't heard any problems in my 2 months of auditions, but I don't play loud - and it seems reasonable to anticipate such problems -
I've certainly seen enough threads where others have mentioned such problems.
My guru had mentioned a material called Q-pad - its a self adhesive sheet product used in car soundproofing.
I mentioned dynamat - something my car audio buddies talked about - he replied:
"NOPE! Dynamats will not get the job done. Q-Pads are a lead-impregnated composite sheets. Dynamats and Q-pads are not the same."
Amazon sells small packs of 6 12" x 12" sheets for about $30 - got some about 2 weeks back.
This is apparently a fiberglass product - sheeting within the tar -
But if it damps it, its certainly a cheap enough process.
So I lad the cabinets down on their face, pulled the back, used a small 1/4 drive ratchet and pulled 2 bolts from the upper flange
holding the horn to the cabinet, and then 1 nut holding the driver and horn to a metal bracket, and pulled the horn.
Its very clean - but I wiped down with alcohol, just to be sure. I figured 1 1/2 sheets of Q-pad would probably do each horn,
so I did some measurements, cut one sheet in half, and trimmed the edges so it would fit the large sides of the horn.
The flanges taper to the main horn body - and are 1.75" at the deepest, so I cut a piece from another sheet, trimmed it to fit the taper,
and used that as a template to make 3 more on that sheet of Q-pad. The material is self sticky, so I peeled off the backing and slipped it into place.
On a hunch, I took the pieces I cut off when I shaped it and used them on the narrow side of the horns - I mean, why not use all the material?
After it was done I took it upstairs, fired up my blow (hair) dryer, and heated the pad up, just to bond it even tighter to the horn.
So, here is the 1 I've done - I'll do the other after dinner or tomorrow. [Its dinner time]
I have some tips for damping the vertical blades on the front - more about that next time!