A loudspeaker diaphragm that is coupled directly to the surrounding air mass of the listening room.
"I couldn't be more pleased with your work. My Dad has been searching many years for an out of print LP. When I found it, I decided it would be better to give it to him on compact disc. After listening to the results, I'm confident this will be the best Christmas gift he's received in years. The audio quality is spectacular and we now longer ..."