VOTT: So I'm not crazy...excellent!

They only miss by about 3/8" with the insulation removed. I think I can get away with a 3/8" strip of wood around the perimeter. The back panel would protrude by that much, but no biggie, it's the back of the speaker anyway. A project for another day. I suppose I could route out a 3/8" deep depression in the existing back panel. That would be about 1/2 the total thickness.

Earl: Thanks for the tip. I'll ring up Bill and see what he has to input.

As far as the sound, they are a little harsh right now. They sound more metallic. The 806s were creamier, if less bright. Is there a break-in period for HF compression drivers like there is for LF drivers?