Term	Definition	Demo
Q	The 'quality factor' of a resonance, related to the amount of damping or losses in the resonating system. High-Q resonances have little damping. They are very frequency specific, or narrow bandwidth, and they ring energetically. Increasing amounts of damping lower the Q, resulting in lower amplitude, wider bandwidth effects in frequency responses, and less ringing in the time responses.
Quadraphonic	Four channel recodings, promoted during the late 1970's, some on tape, but mostly on matrix-encoded two-channel LP's. There was even an attempt to popularize a discrete four channel LP format using signals recorded up to about 50 kHz. It all collapsed because the industry could not agree on a single standard. Some of the clever matrix technology was incorporated in Dolby Stereo and Dolby ProLogic for movie sound tracks.