Glossary of pro audio terms
aliasing Glossary This is a type of distortion caused during the analog-to-digital conversion process. If the frequency of the analog signal exceeds one-half the sampling rate, spurious signals and harmonics not present on the original signal may be created (see Nyquist Theorem). Careful design and filtering before the sampling stage can reduce this aliasing to a minimum.
B bus balanced input An electrical connection common to three or more circuits. In mixer design, a bus usually carries signals from a number of inputs to a mixing amplifier, just like a city bus carries people from a number of neighborhoods to their jobs. It comes from the British “omnibus”. An input consists of two leads, neither of which is common to the circuit ground. This is a “differential pair”, where the signal consists of the difference in voltage between the two leads.
Depending on how used, it can be lovely or grotesque. 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,” making sure the level and EQ are all 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 buses.
Commonly used to describe signal levels in consumer equipment. To convert dBV to dBu, add 2.2 dB. DAW Digital Audio Workstation is a dedicated recording/editing software application and hardware system, used for hard disk (non-linear) random access recording and playback. Many DAWs are used with personal computers using Windows® or Macintosh® operating systems, though some use their own proprietary computers.
dipping dynamic microphone The opposite of peaking, of course, used in audio to describe the shape of a frequency response curve. A dip in an EQ curve looks like a valley, or a dip. Dipping with an equalizer reduces a range of frequencies. (See guacamole.) The class of microphones that generate electrical signals by the movement of a coil in a magnetic field. Dynamic microphones are rugged, relatively inexpensive, capable of very good performance and do not require external power.
Bass and treble controls on your stereo are EQ; so are the units called parametrics and graphics and notch filters. as an insert processor (serial) on a particular input or subgroup, or it may be used via the aux send/return system (parallel). See also echo, reverb. A lot of how we refer to equalization has to do with what a graph of the frequency response looks like.
hold, and release time are some of the adjustable gate parameters. FOH An acronym for Front Of House. See house and main house speakers. Nobody involved with audio ever goes to the Back of House because they never have time to drink enough beer. graphic EQ A graphic equalizer uses slide pots for its boost/ cut controls, with its operating frequencies evenly spaced through the audio spectrum.
system. Never disable the safety ground in an attempt to solve hum problems. Hz Short for Hertz. guacamole Just kidding (see dipping). I H impedance The A.C. resistance, capacitance, and inductance in an electrical circuit, measured in ohms. In audio circuits (and other ac circuits) the impedance in ohms can often be much different from the circuit resistance as measured by a dc ohmmeter.
may have several master controls, which may be slide faders or rotary controls. K mic amp knee See mic preamp. A knee is a sharp bend in a curve (an EQ frequency response or compressor gain curve) not unlike the sharp bend in your leg. mic level The typical level of a signal from a microphone. A mic level signal (usually but not always coming from a microphone) is generally lower than -30 dBu. With a very quiet source (a pin dropping?) the signal can be -70 dBu or lower.
“Why did you mult the flanger into every input in the board?” mixer An electronic device used to combine various audio signals into a common output. Different from a blender, which combines various fruits into a common libation. N monaural noise Long for mono. Literally, pertaining to or having the use of only one ear. Whatever you don’t want to hear.
O bandwidth. “Semi” parametric EQs allow control of fewer parameters, usually frequency and gain (i.e., they have a fixed bandwidth, but variable center frequency and gain). P peaking The opposite of dipping, of course. A peak is an EQ curve that looks like a hill, or a peak. Peaking with an equalizer amplifies a band of frequencies. PA Acronym for Public Address. Today, people who work with PA systems like to say they’re working in “sound reinforcement”. See SR. PFL An acronym for Pre Fade Listen.
tude but are opposite in polarity. The two legs of a differential output are 180 degrees out of phase. The phase reverse switch found on some mixers or mic preamps actually reverses the signal polarity. post-fader A term used to describe an aux send (or other output) that is connected so that it is affected by the setting of the associated channel fader. Sends connected this way are typically (but not always) used for effects. A post-fader output from a mixer channel usually is also post-EQ.
kHz whose -3 dB points are 7.5 kHz and 12.5 kHz has a Q of 2. can do it right on the front panel of many effects units, or you can route the delay return back into itself on your mixer. Can be a great deal of fun at parties. quantization Regeneration is also a fancy name for feedback. Feedback makes oscillators work and reduces distortion in amplifiers. Feedback in sound reinforcement systems, a form of oscillation itself, makes you popular with dogs and unpopular with musicians and audience alike.
effects devices. Mackie mixers call it an Aux Send. RFI Radio Frequency Interference. High frequency radiation that often results from sparking circuits. This can be manifested in a number of ways in audio systems, but is usually evident as a high-frequency buzz or hash sound. shelving A term used to describe the shape of an equalizer’s frequency response.
SR T An acronym for Sound Reinforcement, which refers to the process (or a system for) amplifying acoustic and electronic sounds from a performance or speech so that a large audience can hear clearly. Or, in popular music, so that a large audience can be excited, stunned or even partially deafened by the tremendous amplification. The term “SR” is to “PA” (Public Address) as the term “environmental cleanup technologist” is to “garbage collector”.
tial. Unbalanced circuit connections require only two conductors (signal “hot” and ground). Unbalanced audio circuitry is less expensive to build, but under certain circumstances is more susceptible to noise pickup. W wet A signal with added reverberation or other effect like echo, delay or chorusing. unity gain A circuit or system that has its voltage gain adjusted to be one, or unity. A signal will leave a unity gain circuit at the same level at which it entered – no amplification, but no loss either.
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