main
house speakers
The
main loudspeakers for a sound reinforcement system. These are
usually the largest and loudest loudspeakers, and are usually
positioned so that their sound seems to come from the area of
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mains
See
main house speakers.
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master
A
control affecting the final output of a mixer. A mixer may have
several master controls, which may be slide faders or rotary
controls.
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mic
amp
See
mic preamp.
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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
below -30dBu. With a very quiet source (a pin dropping?) the
signal can be -70dBu or lower. It is also possible for some
microphones to deliver more signal than this, in which case
it may be referred to as a "hot" mic level. Alternatively,
you can just say, "Boy, is that loud!"
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mic
pre
See
mic preamp.
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mic
preamp
Short
for microphone preamplifier. An amplifier that functions to
bring the very low signal level of a microphone (approximately
-50dBu) up to line level (approximately 0dBu). Mic preamps often
have their own volume control, called a trim control, to properly
set the gain for a particular source. Setting the mic preamp
gain correctly with the trim control is an essential step in
establishing good noise and headroom for your mix.
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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.
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monaural
Literally,
pertaining to or having the use of only one ear. In sound work,
monaural has to do with a signal which, for purposes of communicating
audio information, has been confined to a single channel. One
microphone is a mono pickup; many microphones mixed to one channel
is a mono mix; a mono signal played through two speakers is
still mono, since it only carries one channel of information.
Several monaural sources, however, can be panned into a stereo
(or at least two-channel, if you are going to be picky) mix.
Monaural sound reinforcement is common for environments where
stereo sound reinforcement would provide an uneven reproduction
to the listener.
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monitor
In
sound reinforcement, monitor speakers (or monitor headphones
or in-the-ear monitors) are those speakers used by the performers
to hear themselves. Monitor speakers are also called foldback
speakers. In recording, the monitor speakers are those used
by the production staff to listen to the recording as it progresses.
In zoology, the monitor lizard is the lizard that observes the
production staff as the recording progresses. Keep the lizard
out of the mixer.
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mono
Short
for monaural.
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mult
Probably
short for multiple. In audio work, a mult is a parallel connection
in a patch bay or a connection made with patch cords to feed
an output to more than one input. A "Y" cable is a
type of mult connection. Also a verb, as in "Why did you
mult the flanger into every input in the board?"
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noise
Whatever
you don't want to hear. Could be hum, buzz or hiss; could be
crosstalk or digital hash or your neighbor’s stereo; could
be white noise or pink noise or brown noise; or it could be
your mother-in-law reliving the day she had her gallstone removed.
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noise
floor
The
residual level of noise in any system. In a well designed mixer,
the noise floor will be a quiet hiss, which is the thermal noise
generated by bouncing electrons in the transistor junctions.
The lower the noise floor and the higher the headroom, the more
usable dynamic range a system has.
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pan,
pan pot
Short
for panoramic potentiometer. A pan pot is used to position (or
even move back and forth) a monaural sound source in a stereo
mixing field by adjusting the source’s volume between the
left and right channels. Our brains sense stereo position by
hearing this difference in loudness when the sound strikes each
ear, taking into account time delay, spectrum, ambient reverberation
and other cues.
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parametric
EQ
A
"fully" parametric EQ is an extremely powerful equalizer
that allows smooth, continuous control of each of the three
primary EQ parameters (frequency, gain, and bandwidth) in each
section independently. "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). |
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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.
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PFL
An
acronym for Pre Fade Listen. Broadcasters would call it cueing.
Sound folks call it being able to solo a channel with the fader
down.
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phantom
power
A
system of providing electrical power for condenser microphones
(and some electronic pickup devices) from the sound mixer. The
system is called phantom because the power is carried on standard
microphone audio wiring in a way that is "invisible"
to ordinary dynamic microphones. Mackie mixers use standard
+48 volt DC power, switchable on or off. Most quality condenser
microphones are designed to use +48 VDC phantom power. Check
the manufacturer’s recommendations.
Generally, phantom power is safe to use with non-condenser microphones
as well, especially dynamic microphones. However, unbalanced
microphones, some electronic equipment (such as some wireless
microphone receivers) can short out the phantom power and be
severely damaged. Check the manufacturer’s recommendations
and be careful!
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phasing
A
delay effect, where the original signal is mixed with a short
(0 to 10 msec) delay. The time of the delay is slowly varied,
and the combination of the two signals results in a dramatic
moving comb-filter effect. Phasing is sometimes imitated by
sweeping a comb-filter EQ across a signal. A comb filter can
be found in your back pocket.
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phone
jack
Ever
see those old telephone switchboards with hundreds of jacks
and patch cords and plugs? Those are phone jacks and plugs,
now used widely with musical instruments and audio equipment.
A phone jack is the female connector, and we use them in 1/4"
two-conductor (TS) and three-conductor (TRS) versions.
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phone
plug
The
male counterpart to the phone
jack.
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phono
jack
See RCA phono jack.
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phono
plug
See
RCA phono plug.
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post-fader
A
term used to describe an aux send (usually) 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. See pre-fader. |
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pot,
potentiometer
In
electronics, a variable resistor that varies the potential,
or voltage. In audio, any rotary or slide control.
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pre-fader
A
term used to describe an aux send (usually) that is connected
so that it is not affected by the setting of the associated
channel fader. Sends connected this way are typically (but not
always) used for monitors (foldback). See post-fader.
proximity effect
The property of many directional microphones to accentuate their
bass response when the source-to-mic distance is small, typically
three inches or less. Singers generally like this effect even
more than singing in the shower.
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Q
A
way of stating the bandwidth of a filter or equalizer section.
An EQ with a Q of .75 is broad and smooth, while a Q of 10 gives
a narrow, pointed response curve. To calculate the value of
Q, you must know the center frequency of the EQ section and
the frequencies at which the upper and lower skirts fall 3dB
below the level of the center frequency. Q equals the center
frequency divided by the difference between the upper and lower
-3dB frequencies. A peaking EQ centered at 10kHz whose -3dB
points are 7.5kHz and 12.5kHz has a Q of 2.
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RCA
phono jack or RCA jack or phono jack
An
RCA phono jack is an inexpensive connector (female) introduced
by RCA and originally used to connect phonographs to radio receivers
and phono preamplifiers. The phono jack was (and still is) widely
used on consumer stereo equipment and video equipment but was
quietly fading into obscurity in the professional and semiprofessional
sound world. Then phono jacks began cropping up in early project-studio
multitrack recorders, which (unfortunately) gave them a new
lease on life. Since so many stereo recorders are fitted with
them, we decided we’d have to put a couple on our mixers
for your convenience. But make no mistake: the only thing that
the phono jack (or plug) has going for it is low cost.
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RCA
phono plug
The
male counterpart to an RCA phono jack. See above.
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regeneration
Also
called recirculation. A delay effect created by feeding the
output of a delay back into itself to cause a delay of the delay
of the delay. You 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.
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return
A
return is a mixer line input dedicated to the task of returning
processed or added sound from reverb, echo and other effects
devices. Depending on the internal routing of your mixer and
your own inclination, you could use returns as additional line
inputs, or you could route your reverb outputs to ordinary line
inputs rather than the returns.
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reverberation,
reverb
The
sound remaining in a room after the source of sound is stopped.
It’s what you hear in a large tiled room immediately after
you’ve clapped your hands. Reverberation and echo are terms
that can be used interchangeably, but in audio parlance a distinction
is usually made: reverberation is considered to be a diffuse,
continuously smooth decay of sound, whereas echo is a distinct,
recognizable repetition of a word, note, phrase or sound. Reverberation
and echo can be added in sound mixing by sending the original
sound to an electronic (or electronic/acoustic) system that
mimics natural reverberation, or worse. The added reverb is
returned to the blend through additional mixer inputs. Highly
reverberant rooms are called live; rooms with very little reverberation
are called dead. A sound source without added reverb is dry;
one with reverb or echo added is wet.
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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. |
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RMS
An
acronym for Root Mean Square, a conventional way to measure
AC voltage and audio signal voltage. Most AC voltmeters are
calibrated to read RMS volts. Other conventions include average
volts, peak volts and peak-to-peak volts.
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Sa
value
A
measure of the relative liveness of a room. A low Sa means a
very live room, and a high Sa means a dead room. S = the total
surface area of the room, and a = the average absorption coefficient
of all the surfaces.
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send
A
term used to describe a secondary mix and output of the input
signals, typically used for foldback monitors, headphone monitors,
or effects devices. Mackie mixers call it an Aux Send.
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shelving
A
term used to describe the shape of an equalizer’s frequency
response. A shelving equalizer’s response begins to rise
(or fall) at some frequency and continues to fall (or rise)
until it reaches the shelf frequency, at which point the response
curve flattens out and remains flat to the limits of audibility.
If you were to graph the response, it would look like a shelf.
Or more like a shelf than a hiking boot. The EQ controls on
your stereo are usually shelving equalizers. See also peaking
and dipping.
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slap,
slapback
A
single-delay echo without any repeats. Also see echo.
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solo
Italian for alone. In audio mixers, a solo circuit allows the
engineer to listen to individual channels, buses or other circuits
singly or in combination with other soloed signals.
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sound
reinforcement
A
system of 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.
Means essentially the same thing as PA (Public Address).
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SR
An
acronym for Sound Reinforcement
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steradians
Just
as a radian is an angular unit of measure in 2-dimensional space,
so a steradian is an angular unit of measure in 3-dimensional
space (solid angle).
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stereo
Believe
it or not, stereo comes from a Greek word that means solid.
We use stereo or stereophony to describe the illusion of a continuous,
spacious soundfield that is seemingly spread around the listener
by two or more related audio signals. In practice, stereo often
is taken to simply mean two channels.
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sweep
EQ
An
equalizer that allows you to "sweep" or continuously
vary the frequency of one or more sections.
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symmetrically
balanced
See
balanced.
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tinnitus
The
ringing in the ears that is produced with prolonged exposure
to high volumes. A sound in the ears, such as buzzing, ringing,
or whistling, caused by volume knob abuse! |
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trim
In
audio mixers, the gain adjustment for the first amplification
stage of the mixer. The trim control helps the mixer cope with
the widely varying range of input signals that come from real-world
sources. It is important to set the trim control correctly;
its setting determines the overall noise performance in that
channel of the mixer. See mic preamp.
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TRS
Acronym
for Tip-Ring-Sleeve, a scheme for connecting three conductors
through a single plug or jack. 1/4" phone plugs and jacks
and 1/8" mini phone plugs and jacks are commonly wired
TRS. Since the plug or jack can carry two signals and a common
ground, TRS connectors are often referred to as stereo or balanced
plugs or jacks. Another common TRS application is for insert
jacks, used for inserting an external processor into the signal
path. In Mackie mixers, the tip is send, ring is return, and
sleeve is ground.
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TS
Acronym
for Tip-Sleeve, a scheme for connecting two conductors through
a single plug or jack. 1/4" phone plugs and jacks and 1/8"
mini phone plugs and jacks are commonly wired TS. Sometimes
called mono or unbalanced plugs or jacks. A 1/4" TS phone
plug or jack is also called a standard phone plug or jack.
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unbalanced
An
electrical circuit in which the two legs of the circuit are
not balanced with respect to ground. Usually, one leg will be
held at ground potential. 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. |
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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. In Mackie mixers, unity gain is achieved
by setting all variable controls to the marked "U"
setting. Mackie mixers are optimized for best headroom and noise
figures at unity gain |
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VLZ
Acronym
for very low impedance. (Impedance is measured in ohms represented
by the symbol,
which is the last letter of the Greek alphabet. This is how
the letter Z is used instead of I.) VLZ is one of the most important
reasons why inherent noise levels on Mackie mixing boards are
so minuscule. Thermal noise is something that’s created
by all circuitry and usually transistors and resistors are the
worst culprits. The basic rule with thermal noise is: the higher
the impedance, the more the noise. Mackie’s VLZ design
reduces thermal noise by making internal impedances as low as
possible in as many places as possible within the console. VLZ
is achieved by scaling down resistor values by a factor of three
or four -- resulting in a corresponding reduction in thermal
noise. This is especially true for the console’s mixing
buses.
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volume
Electrical
or sound level in an audio system. Perhaps the only thing that
some bands have too much of.
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VRMS
See
RMS.
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wet
With
added reverberation or other effect like echo, delay or chorusing. |
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XLR
connector
A
three-pin connector used in audio for transmitting a balanced
signal. Sometimes referred to as a Cannon connector, named for
the manufacturer who first popularized the three-pin connector.
See Cannon.
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