Direct Current (cf. AC). The form of electrical current supplied by batteries and the power supplies inside electrical equipment. The current flows in one direction only.

A means of measuring the slope or steepness of a filter. The gentlest audio filter is typically 6dB/Octave (also called a first-order slope). Higher values indicate sharper filter slopes. 24dB/octave (fourth order) is the steepest normally found in analogue audio applications.

Information stored and used by a computer.

An abbreviation of Digital Audio Tape, but often used to refer to DAT recorders (more correctly known as R-DAT because they use a rotating head similar to a video recorder). Digital recorders using fixed or stationary heads (such as DCC) are known as S-DAT machines.

The control of a resonant device. In the context of reverberation, damping refers to the rate at which the reverberant energy is absorbed by the various surfaces in the environment. In the context of a loudspeaker it relates to the cabinet design and internal acoustic absorbers.

An arrangement of sharing a common data signal between multiple devices. A ‘daisy chain’ is created by connecting the appropriate output (or through) port of one device to the input of the next. This configuration is often used for connecting multiple MIDI instruments together: the MIDI Out of the master device is connected to the MIDI In of the first slave, then the MIDI Thru of the first slave is connected to the MIDI In of the second slave, and so on... A similar arrangement is often used to share a master word clock sample synchronising signal between digital devices.

see Control Voltage

One complete vibration (from maximum peak, through the negative peak, and back to the maximum again) of a sound source or its electrical equivalent. One cycle per second is expressed as 1 Hertz (Hz).

The frequency above or below which attenuation begins in a filter circuit.

The ability to copy or move sections of a recording to new locations.