Re: 340SE and BT77
Here is what I did. In addition to the clamping, I attached an old screw type speaker mount to the rear of the 340. Then I took a piece of industrial strength velcro and fasened it around the screw type speaker mount to the bottom of the BT-77 mount. This takes a bit of the load off the BT-77's clamps and just reinforces it overall. Mine has not moved one bit in almost two years!
L/R - Sierra Towers
Center - Sierra Horizon Tower
Surrounds - 200SE
SW - Dual PSA XV15's
TV - Panasonic TC-P65VT60
A/V Receiver - Denon AVR-4311CI
Blu-ray/DVD - Sony BDP-S5100
DVR STB - Motorola Arris X1