SoundCraft MFX manual Glossary, Afl

GLOSSARY

AFL	After-fade listen: a function that allows the operator to monitor the post-fade signal in
	a channel independently of the main mix.
Auxiliary send	An output from the console comprising a mix of signals from channels derived inde-
	pendently of the main stereo mix.
Balance	The relative levels of the left and right channels of a stereo signal.
Balanced	A method of audio connection which ‘balances’ the wanted signal between two wires,
	these wires also have a screen which carries no signal. Any interference is picked up
	equally by the two wires, which results in cancellation of the unwanted signal. In this
	guide, the term can refer to various circuit architectures. Connection details are given
	in relevant sections.
Clipping	The onset of severe distortion in the signal path, usually caused by the peak signal
	voltage being limited by the circuit’s power supply voltage.
DAT	Digital Audio Tape, a cassette-based digital recording format.
dB (decibel)	A ratio of two voltages or signal levels, expressed by the equation dB=20Log10 (V1/
	V2). Adding the suffix ‘u’ denotes the ratio is relative to 0.775V RMS.
DI(direct injection)/DI Box		The practice of connecting an electric musical instrument directly to the
	input of the mixing console, rather than to an amplifier and loudspeaker which is
	covered by a microphone feeding the console.
Equaliser	A device that allows the boosting or cutting of selected bands of frequencies in the
	signal path.
Fader	A linear control providing level adjustment.
Feedback	The `howling’ sound caused by bringing a microphone too close to a loudspeaker
	driven from its amplified signal.
Foldback	A feed sent back to the artistes via loudspeakers or headphones to enable them to
	monitor the sounds they are producing.
Frequency response	The variation in gain of a device with frequency.
Gain	The amount of amplication in level of the signal.
Headroom	The available signal range above the nominal level before clipping occurs.

Impedance balancing A technique used on unbalanced outputs to minimise the effect of hum and interfer-

	ence when connecting to external balanced inputs.
Insert	A break point in the signal path to allow the connection of external devices, for in-
	stance signal processors or other mixers at line level signals. Nominal levels can be
	anywhere between 0dBu to +6dBu, usually coming from a low impedance source.
Pan (pot)	Abbreviation of ‘panorama’: controls the levels sent to left and right outputs.
Peaking	The point at which a signal rises to its maximum instantaneous level, before falling
	back down again. It can also describe an equaliser response curve affecting only a
	band of frequencies, (like on a graphic equaliser), “peaking” at the centre of that
	band.
Peak LED	A visual indication of the signal peaking just before the onset of clipping, which will
	distort the signal.
PFL	Pre-fade listen: a function that allows the operator to monitor the pre-fade signal in a
	channel independently of the main mix.
Phase	A term used to describe the relationship of two audio signals. In-phase signals rein-
	force each other, out-of-phase signals result in cancellation. Phase is a measurement
	of relative displacement between two waves of identical frequency.
Polarity	A term used to describe the orientation of the positive and negative poles of an audio
	connection. Normally connections are made with positive to positive, negative to
	negative. If this is reversed, the result will be out-of-phase signals (see ‘phase’ above).
Post-fade	The point in the signal path after a fader and therefore affected by the fader position.

46