- The range of frequencies affected by a control. The "width" of a control. How wide a range of frequencies is affected when you adjust a specific control such as on a graphic equalizer. A parametric equalizer includes a "Q" control which allows the user to make changes to a wide range of frequencies or just a narrow band of frequencies.
- In loudspeakers, the directional property of the speaker. An omnidirectional speaker has a Q of 1, and a loudspeaker radiating into a hemisphere has a Q of 2. Source: Church Audio & Acoustics Glossary
- Electronics: A symbol for the figure of merit of an inductor or resonant circuit.