D. 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.
Assign
To route a signal to a particular signal path or combination of signal paths.
Attenuate
To reduce signal level.
Auxiliary Send
An output from the console comprising a mix of signals from the chan- nels derived independently of the left, right and group mixes.
Balanced
A method of connecting audio signals using 3 wires. Two of the wires carry the audio signal out of phase from each other allowing common mode rejection of in phase noise that may be picked up on each wire. The third wire is the ground. The common use is with the XLR con- nectors on mics and mixer outputs. Also the 1/4” phone TRS (Tip/Ring/Sleeve) system is used for making balanced connections.
Bandwidth
The band of frequencies that pass through a device with a loss of less than 3dB, expressed in Hertz.
Cardioid
Cardioid refers to the heart-shape sensitivity pattern of some directional microphones.
Chorusing
An effect available in some digital delay effects units and reverbs. Chorusing involves a number of moving delays and pitch shifting, usu- ally panned across a stereo field.
Clipping
The onset of distortion in the signal path, usually caused by the peak signal voltage being limited by the circuit’s power supply voltage.
Condenser
Another term for the electronic component generally known as a capac- itor. In audio, condenser usually refers to a type of microphone that uses a capacitor as the sound pickup element. Condenser microphones require electrical power to run internal amplifiers and maintain an electrical charge on the capacitor. They are typically powered by internal batteries or “phan- tom power” supplied by an external source, such as a mixing console.
Console
A term for a sound mixer, usually a large desk-like mixer.
Cueing
In broadcast, stage and post-production work to “cue up” a sound source (a record, a sound effect on a CD, a song on a tape) means to get it ready for playback by making sure you are in the right position on the “cue,” or making sure the level and EQ are set properly. This requires a special monitoring circuit that only the mixing engineer hears. It does not go out on the air or to the main mixing busses. This “cueing” cir- cuit is the same as the PFL feature on a mixer.
DAT
Digital Audio Tape, a tape-based digital recording format.
dB (see decibel)
A ratio of two voltages or signal levels, expressed by the equation dB=20Log 10 (V 1 /V 2 ).
dBm
A unit of measurement of audio signal level in an electrical circuit expressed in decibel referenced to 1 milliwatt. The “m” in dBm stands
for “milliwatt.” In a circuit with an impedance of 600 ohms, this refer- ence (0dBm) corresponds to a signal voltage of 0.775 VRMS (because 0.775 V across 600 ohms equals 1mw).
dBu
A unit of measurement of audio signal level in an electrical circuit, expressed in decibel referenced to 0.775 VRMS into any impedance. Commonly used to describe signal levels within a modern audio system.
dBv
A unit of measurement equal to the dBu but no longer in use. It was too easy to confuse a dBv with a dBV, to which it is not equivalent.
dBV
A unit of measurement of audio signal level in an electrical circuit, expressed in decibel referenced to 1 VRMS across any impedance. Commonly used to describe signal levels in consumer equipment. To convert dBV to dBu, add 2.2dB.
Decibel (see dB)
The dB is a ratio of quantities measured in similar terms using a loga- rithmic scale. Many audio system parameters measure over such a large range of values that the dB is used to simplify the numbers. A ratio of 1000V:1V=60dB. When one of the terms in the ratio is “an agreed upon standard value” such as 0.775V, 1V or 1mw, the ratio becomes an absolute value, i.e., +4dBu, –10dBV or 0dBm.
Delay
In sound work, delay usually refers to an electronic circuit or effects unit whose purpose it is to delay the audio signal for some short period of time. Delay can refer to one short repeat, a series of repeats or the complex interactions of delay used in chorusing or reverb. When delayed signals are mixed back with the original sound, a great number of audio effects can be generated, including phasing and flanging, dou- bling, Haas-effect positioning, slap or slap back, echo, regenerative echo, chorusing and hall-like reverberation. Signal time delay is central to many audio effects units.
Detent
A point of slight physical resistance (a click) in the travel of a knob or slide control.
DI(direct injection)
The practice of connecting an electric musical instrument directly to the input of the mixing console rather than using a microphone into the con- sole.
Direct output
A post fader line level output from the input channel, bypassing the sum- ming amplifiers, typically for sending to individual tape tracks during recording.
Doubling
A delay effect, where the original signal is mixed with a medium (20 to 50 msec) delay.
Dry
Usually means without reverberation or without some other applied effect like delay or chorusing.
Dynamic Microphones
Refers to the class of microphones that generate electrical signals by the movement of a coil in a magnetic field. Dynamic microphones do not require external power.
Dynamic range
The range between the maximum and minimum sound levels that a sound system can produce. It is usually expressed in decibels as the differ- ence between the level at just before peak clipping and the level of the noise floor.