Acoustat repair or rebuild in Texas???

Just a thought, but it is easy. A close inspection might reveal the problem. Take a flashlight and shine it through from the back. See if both speakers have similar vertical strips glued on the plastic grid. Mine had lost one in shipping and this caused a rattle during loud passages. A little contact glue and it was good as new.
If a frame is cracked or broken I would remove the socks and see if there was a difference between the two sides as far as attachment to the panel or any damage to same.

Unplug the speakers and allow them to discharge for 24 hours before you touch anything that might be part of the circuit. High voltage can kill you!!!!
You can take the metal plate off the top of the speaker (not the base where the power supply is but the actual top of the 7.5 ft. speaker) by removing the eight or ten screws. Then use a thin screwdriver to pry off the staples which hold the cloth to the wood. Then roll the fabric down as you would a sock being careful to keep your fingers out of the electrical works. Carefully compare the two speakers to see what may be amiss. You may Email me at [email protected] if you want to have further instructions, but this should get you started.