1-20
* This is an input with far greater sensitivity than the "Line Input".
Line Inputs typically accomodate input voltages of 200 millivolts to 2 volts,
whereas Mic Inputs will accomodate input signals of 10 to 100 millivolts. This
input is sometimes called a "High gain" input, because It is designed to amplify
low level signals. There are two main differences between a Mic and Line input.
This is why this input connector (XLR type) looks much different than the Line
Input connection (1/4" phone plug type).
AA
AA
))
))
The "XLR" type input connection is designed for low impedance,
balanced signals. Low impedance simply means lower resistance to A.C. current
sent from the microphone. Low imimpedance mic's by definition offer very little
resistance to A.C. current allowing very long mic cables without significant
signal loss. The fact that low impedance cable runs produce very little line losses
makes this type of input especially well suited to long mic cable runs, snakes, or
mic cord extensions.
BB
BB
))
))
The input is "Balanced". This term works closely in hand with the
term "Common Mode Rejection" for the mic input of your console. As a low level
signal is transmitted down a wire to the Mic input of your console there is a good
chance that extraneous voltages such as 60Hz power line sources could be injected
into the cable, and later amplified by the console. What balancing does is
eliminate much of this "Stray field" by cancelling it at the input of the console.
This is called "Common Mode Rejection", and allows for long mic cable runs
without the risk of picking up significant hum or other extraneous signals.
Balanced cables feature (3) wires: a ground wire, in-phase wire, and out-of-phase
wire. When the in-phase and out-of-phase signals are summed at the input of the
console the extraneous noise is rejected, or cancelled. The amount of this rejection
is expressed as "Common Mode Rejection". So, balanced cables offer the lowest
possible hum and noise when running long cables.
* Microphone cables are always "Shielded". This means that the signal
wire within the mic cord is surrounded by tightly braided or solid "Ground" or
shield wire. This is done so that any potential injected signals (stray field) must
first pass through the ground wire prior to affecting the signal wire at the center
of the cable. Mic level and pre-amp level cables should always be shielded for the
lowest possible noise.
SS
SS
EE
EE
CC
CC
TT
TT
II
II
OO
OO
NN
NN
##
##
33
33
--
--
11
11
88
88
* By this time you should be deducing that a "Balanced, Low
Impedance" mic is the best to use with this input. With a properly shielded cord, it
will provide the best overall performance and lowest possible noise.
33
33
))
))
CC
CC
hh
hh
aa
aa
nn
nn
nn
nn
ee
ee
ll
ll
DD
DD
ii
ii
rr
rr
ee
ee
cc
cc
tt
tt
OO
OO
uu
uu
tt
tt
pp
pp
uu
uu
tt
tt
* This is a post fader direct output featured on each channel. It may be
used as a direct input to a multi-track tape recorder, Auxiliary Effects send, a Cue
send, etc. If you have assigned a channel to one of the output channels you may
still utilize the direct output. This allows the output to be used as an auxiliary send
controlled by the Channel Fader, because the channel will feed the Output
Channels and the Direct Output simultaneously. Another way to assign a channel
to the multi-track tape recorder would be to use the channel direct outputs. The
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