A system for tensioning a membrane within a frame for a loudspeaker or a microphone is characterized by a frame containing an opening, a membrane connected to an exterior surface of the frame and spanning the frame opening, and a tensioning device connected with the frame for deflecting a portion of the membrane within the frame opening. The obstacle may be held to the switch-obstacle position by a spring, which may be overcome by applying force to a release mechanism. The averaging circuit is configured to receive N pieces of output signals from the N pieces of internal circuits, averaging the output signals, and output an averaged signal.