Alesis 1622 Reference Manual page 41

or QUADRAVERB. The effect of flanging, either electronically or mechanically done, is
achieved by slightly delaying a signal, then constantly varying the amount of time delay. The
delayed signal is then mixed back with the original signal to produce the "swishing" or "tunneling"
sound.
Gate - See "Noise Gate".
Graphic Equalizer - Seen on sound systems, some home stereos, and many guitar type
amplifiers, this device gets its name from the fact that the control settings actually form a graph
of the frequency spectrum. While shelving equalizers work on broad sections of the frequency
bandwidth, a graphic equalizer divides the frequency spectrum into sections called bands which
are normally measured in musical octaves. An example of a graphic equalizer is the Alesis M-
EQ 230 .
Ground Lift - An adapter for an AC line plug that converts it from 3 pin operation to 2 pin. This
is frequently used to avoid ground loops (see Ground Loops).
Ground Loops - When a sound system or recording system has a loud hum or buzz, a Ground
Loop is usually the cause. Ground Loops are created by having more than one ground point in a
sound system. (See Section 5 - GROUNDING).
Headroom - The amount of available operating level before a circuit is overloaded and begins
to distort. For example, the nominal operating level of the 1622 MIXER is +4dBV and the
maximum output level is +20dBV which means that there is 16dB of headroom available. If the
nominal operating level is -10dBV and the maximum output level is +20dBV, then there is 30dB
of headroom available.
High Impedance - Any impedance which is 10,000 ohms or more is considered a High
Impedance. The inputs of most audio devices are High Impedance. All inputs except the
microphone inputs of the 1622 MIXER are High Impedance.
Inserts - Inserts are used to connect signal processing devices into the signal path of a single
channel. Normally, this is a device that shapes the dynamics or tone of a signal, such as a
compressor, gate, or EQ, rather than an effects device such as a reverb.
An insert consists of both an input and an output and is used to place an outboard effects device,
such as a compressor, EQ, or chorus, into the signal path of only that channel. Each Input
Channel, the Sub Groups, and the Master Outputs of the 1622 MIXER have inserts.
LED - LED is an abbreviation for Light Emitting Diode and is commonly used as an indicator on
audio and musical equipment.
Line Level - The output of most mixers and outboard equipment, which may be nominally -
10dBV or +4dBV, or approximately .1 to 1 volt AC. Because the signal level is so high, costly
low noise precision amplifiers are no longer required. See "Nominal Level"
Low Impedance - Any impedance 1,000 ohms or lower is considered to be Low Impedance.
The outputs of most audio devices and electronic musical instruments are Low Impedance. Most
microphone inputs are Low Impedance. The microphone inputs of the 1622 MIXER are Low
Impedance.
Mix-Minus - A mix-minus feed, which is used for international versions of a film or video, is a
separate mix containing all music and effects, but no dialog (which is usually dubbed in later).
See Section 3, VIDEO POST PRODUCTION
Mixer - A unit which blends several audio sources, such as microphones, tapes, records, or
CDs, together in a single mono or stereo output.
Mixing Console - A Mixing Console blends several audio sources together with the capability
of routing different mixes to several different output combinations.
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