Mackie DL16S Owner's Manual page 26

DL16S • DL32S Owner's Manual
Glossary Of Terms Continued...
Filter — A simple equalizer designed to remove certain ranges of frequencies. The high-pass filter attenuates frequencies
below its cutoff frequency.
FOH — Front Of House. See house and main (house) speakers. No engineer ever goes to the BOH because there's never enough
time to drink beer.
Frequency — The number of times an event repeats itself in a given period of time. Generally, the time period for audio
frequencies is one second, and frequency is measured in cycles per second, abbreviated Hz, honoring Dr. Heinrich Hertz
(who did not invent the rental car company). One Hz is one cycle per second. One kHz (kilohertz) is 1000 cycles per second.
The audio frequency range is generally considered to be 20 Hz to 20,000 Hz (or 20 kHz). This covers the fundamental pitch
and most overtones of musical instruments.
Gain — The measure of how much a circuit amplifies a signal. Gain may be stated as a ratio of input to output voltage, current
or power, such as a voltage gain of 4, or a power gain of 1.5, or it may be expressed in decibels, such as a line amplifier with
a gain of 10 dB.
Gain Stage — An amplification point in a signal path, either within a system or a single device. Overall system gain is distributed
between the various gain stages.
Gate — A dynamics processor that automatically turns off an input signal when it drops below a certain level. This can reduce
the overall noise level of your mix by turning off inputs when they are not in use. Threshold, attack time, hold, and release time
are some of the adjustable gate parameters.
Graphic EQ — The graphic equalizer uses sliders for its boost / cut controls, with its operating frequencies evenly spaced
through the audio spectrum. In a perfect world, a line drawn through the centers of the control shafts would form a graph
of the frequency response curve. Or, the positions of the sliders give a graphic representation of boost or cut levels across
the frequency spectrum.
Ground — Also called earth. Ground is defined as the point of zero voltage in a circuit or system, the reference point from which
all other voltages are measured.
In electrical power systems, ground connections are used for safety purposes, to keep equipment chassis and controls
at zero voltage and to provide a safe path for errant currents. This is called a safety ground. Maintaining a good safety ground
is essential to preventing electrical shock. Follow manufacturer's suggestions and good electrical practices to ensure a safely
grounded system. Never remove or disable the grounding pin on the power cord.
In sensitive electronic equipment, tiny currents and voltages riding on the ground (so it's not truly zero volts) can cause noise
in the circuits and hamper operation. Often a ground separate from the power ground is used as the reference point for the
electronics, isolating the sensitive electronics from the dirty power ground. This is called a technical ground.
Quality audio equipment is designed to maintain a good technical ground and also operate safely with a good safety ground.
Ground Loop — A ground loop occurs when the technical ground within an audio system is connected to the safety ground
at more than one place. This forms a loop around which unwanted current flows, causing noise in the audio system. Never
disable the safety ground in an attempt to solve hum problems.
Guacamole — A delicious dip comprised mostly of avocados. Speaking of dips, refer to dipping.
Hertz — The unit of frequency, equal to 1 cycle per second. 1000 Hz equals 1 kHz.
House — In audio-land, the house refers to the systems (and even persons) responsible for the primary sound reinforcement
in a given venue. Hence, we have the house mixer or house engineer, the house mix, house mix amps, main house speakers, etc.
Hz — Short for Hertz.
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