Mackie glossary Manuel D’Utilisation

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9
system. Never disable the safety ground in an 
attempt to solve hum problems.
 
guacamole
 
 
H
 
Haas precedence effect
 
A psychoacoustic effect in which the time of 
arrival of a sound to the left and right ears 
affects our perception of direction. If a signal is 
presented to both ears at the same time and at 
the same volume, it appears to be directly in 
front of us. But if the signal to one ear, still at 
the same volume, is delayed slightly, the sound 
appears to be coming from the earlier (non-
delayed) side. 
 
headroom
 
The difference between nominal operating level 
and peak clipping in an audio system. A mixer 
with a nominal operating level of +4 dBu and a 
maximum output level of +22 dBu has 18 dB 
of headroom. Plenty of room for surprise peaks.
 
Hertz
 
The unit of frequency, equal to 1 cycle per sec-
ond. Abbreviated Hz. kHz 1000 Hz, and is usu-
ally pronounced “kay”(with “Hertz” implied) 
by sound professions who ask for “a little more 
two and a half K” when they want you to boost 
2.5 kHz.
 
house
 
In Sound Reinforcement parlance, “house” 
refers to the systems (and even persons) respon-
sible for the primary sound reinforcement in a 
given hall, building, arena or “house.” Hence 
we have the house mixer or house engineer, the 
house mix, the house mix amps, the main 
house speakers and so on.
 
Hz
 
Short for Hertz.
 
I
 
impedance
 
The A.C. resistance, capacitance, and induc-
tance in an electrical circuit, measured in ohms. 
In audio circuits (and other ac circuits) the 
impedance in ohms can often be much differ-
ent from the circuit resistance as measured by a 
dc ohmmeter.
Maintaining proper circuit impedance relation-
ships is important to avoid distortion and mini-
mize added noise. Mackie input and output 
impedances are set to work well with the vast 
majority of audio equipment.
 
input module
 
A holdover from the days when the only way 
that real consoles were built was in modular 
fashion, one channel per module. See channel 
strip.
 
insert
 
Noun – a place where a signal path can be bro-
ken and a processing device placed in line with 
the signal. It’s usually a TRS jack with one con-
ductor being an output (send) and the other 
being an input (return). The jack is wired with a 
 
normalled connection
 
 so that with nothing 
plugged in, the send and return are connected 
together, as if it wasn’t even there. In Mackie 
mixers, the 
 
insert
 
 jacks are wired with tip as 
send, ring as return, and sleeve as ground.
Verb – we don’t want to go there.
 
J