The most basic skill any audio engineer must master is an
understanding of signal flow. Signal flow is the path audio must follow to
reach its intended destination. Basic audio signal flow with regards to
recording consoles falls into two basic sections, the channel path and the
monitor path. Each of these paths has a different task, though the operation
and basic layout is quite similar.
The channel path of a recording console has one specific
task; moving audio from the microphone to the multi-track recorder. The signal
begins at the microphone transducer and moves into the mic panel. The signal
then moves through the pad, phantom power, preamp and mic trim. This collective
section is generally referred to as the mic preamp. Next in line is the phase
switch, which can flip the polarity of the audio signal. Following the phase
switch are the filters, the most commonly used of which is the high-pass
filter. The next component is the equalizer, which can be used to boost or
attenuate specific frequencies or bands of frequencies within the signal. The
insert sends and returns follow the equalizer, and these can be used to patch
in pieces of equipment not directly attached to the console. Next is the
channel fader, which is essentially a variable amplifier before the multi
track. After the fader is the odd/even pan pot, and the routing matrix. The
routing matrix is used to assign channels from the console to channels into the
multi track recorder.
The Monitor path is used to hear the audio coming out of the
multi track recorder. The first item in line coming out of the multi track is
the cue sends. These are used to send audio to artists in the live room, where
they can hear it. Next in line is the monitor fader, which operates much the same
as the channel fader. The monitor fader is much more likely to have adjustments
made, as moving the channel fader from unity gain can add distortion and noise
to the recorded signal. Following the monitor fader are the aux sends. These
are often used to patch in temporal effects such as reverb and delay. The aux
sends can be attenuated, unlike the insert sends and returns that they operate
similarly to. Next in line is the monitor pan pot. This pan is used to move the
signal to the left or right within the stereo field. After the monitor pan is
where the signal from the aux sends returns to the console. This is referred to
as the aux return. The signal from the monitor pans and the aux returns are
then summed into two channels in the stereo bus. The signal from the stereo bus
then passes through the master fader, where it is then sent to a control room
amplifier, and finally to the left and right monitors.
Each of these stages allows a recording or mixing engineer
to control certain aspects of the signal and refine the sonic characteristics
of the audio. It should be noted that many consoles allow the audio engineer to
change the order of some of the individual components within the signal flow.
Therefore, the engineer should understand the particular signal flow of their
console and when to make necessary adjustments to that signal flow.
References
