Q - Ratio of reactance to resistance (series circuit), or resistance to reactance (parallel circuit).
Qa - The system’s Q at Fb, due to absorption losses.
Qec - The system’s Q at resonance (Fc), due to electrical losses.
Qes - The drivers Q at resonance (Fs), due to electrical losses.
Ql - The system’s Q at Fb, due to leakage losses.
Qmc - The system’s Q at resonance (Fc) does to mechanical losses.
Qms - The driver’s Q at resonance (Fs), due to mechanical losses.
Qp - The system’s Q at Fb, due to port losses (turbulence, viscosity, etc.).
Qtc - Measurement of a speaker and enclosure working together as one.
Qts - The measurement of the speaker as a motor, taking into consideration all mechanical and electrical losses.
Quad Voice Coil (QVC) - A subwoofer that has four separate voice coils. The subwoofer or driver itself having 4 positive leads and 4 negative leads. This amount of voice coils make wiring many different loads to possible.
Quiescent Current - The term given to describe the amount of current consumed by a circuit when it is not performing any work (sometimes referred to as standby current). Battery life is determined by the total current drain composed of quiescent current and load current.