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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 con-
tinuous, spacious soundfield that is seemingly
spread around the listener by two or more re-
lated audio signals. In practice, stereo often is
taken to simply mean two channels.
sweep EQ
An equalizer that allows you to “sweep” or
continuously vary the frequency of one or more
sections.
symmetrically balanced
See
balanced.
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!
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.
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 con-
nectors are often referred to as stereo or
balanced plugs or jacks. Another common TRS
application is for insert jacks, used for insert-
ing an external processor into the signal path.
In Mackie mixers, the tip is send, ring is re-
turn, and sleeve is ground.
TS
Acronym for Tip-Sleeve, a scheme for con-
necting 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.
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 re-
quire only two conductors (signal “hot” and
ground). Unbalanced audio circuitry is less
expensive to build, but under certain circum-
stances is more susceptible to noise pickup.
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 opti-
mized for best headroom and noise figures at
unity gain.
VLZ
Acronym for very low impedance.
(Impedence is measured in ohms represented
by the
Ω
symbol, which is the last letter of the
Greek alphabet. This is why 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 cir-
cuitry 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 ther-
mal 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.
volume
Electrical or sound level in an audio system.
Perhaps the only thing that some bands have
too much of.
VRMS
See
RMS.
wet
With added reverberation or other effect
like echo, delay or chorusing.
XLR connector
See
Cannon.
