Recording - November 2017 - 51

days of digital audio. Earlier devices
maxed out at 16 bits and also suffered
from poor or nonexistent dithering in
the conversion process. Higher bit rates
and better converters and mix engines
built on floating-point math have improved things tremendously on the digital
front. That said, I think it still makes
practical sense to stick with the oldschool formula for setting input levels.

FIXING IT IN THE MIX(ER)
Analog mixers are designed so that
outputs of various stages-preamps,
EQs, compressors, inserts, etc.-will
match the input of what follows in the signal path if unity gain is maintained. Digital
mix engines are also designed that way,
but in the digital world it's surprisingly
easy to get away from unity gain.
As mentioned before, modern digital audio has tremendous amounts of
headroom. It's easy to have a very hot
signal in one or more tracks of your mix
without hearing any distortion on the
individual channels! Common culprits
include synths or virtual instruments
played at full MIDI velocity, loops with
pre-normalized levels, and just plain
bad recording technique.
These hot signals may sound OK on
their own, but once placed into a mix
and routed through plug-ins etc. they
can start to wreak sonic havoc. This can
reveal itself in subtle ways; you might
not hear it as distortion or noise, necessarily, but it will definitely degrade the
quality of your recordings as you compensate for them with bad technique.
Compensating for a too-hot signal
by bringing down a virtual mixer fader
degrades the signal path, as you are
not reclaiming any headroom. Turning
the fader down also doesn't lower the
signal going into any plug-ins you insert
on that channel. Many plug-ins don't
handle high levels elegantly; curiously,
that seems most apparent to me on plugins that emulate analog gear. Go figure.
A much better solution is to attenuate
the sound closer to the source. For audio
that's too hot, I go to the waveform
view in my DAW and adjust the volume
there. Some DAWs allow you to do
this visually, others by way of a dialog.

Virtual instruments are best level-controlled
within the VI itself (every softsynth has a
master output knob).
It's also easy to unwittingly boost gain
when using plug-ins. EQs with one or
more bands set to significant boosts,
and compressors with too much makeup
gain, are particular culprits. These overcooked signals can easily be passed on
to the next step in the signal path.
Fortunately most plug-ins have input
and output level controls. If big EQ
boosts are needed, lower the output level
to compensate. Compressors can be
sneaky-many developers add a couple
of dB of makeup gain to their presets.
You get seduced by the louder sound,
but when mixing, you may end up trying
to compensate for the extra volume by
lowering the channel fader. The better
option is to to turn down the compressor's
output or back off its makeup gain.
Another common gain staging issue
(analog or digital) is overloading the
master section. Often the fix is to put a
limiter at the end of the chain to prevent
clipping, but the damage is already
done by that point. A better sounding
option is to build your mix with proper
levels and gain staging throughout. It's
also a good practice to group tracks
or assign them to buses or VCAs. Controlling the level of those submixes is an
efficient and good-sounding technique
for managing gain to the master output.

SIGNAL PATHS TO GLORY
What I've given you here is a good
introduction and starting point to managing gain and getting the best recordings
possible. No single overview can cover
every signal path, but these basics will
almost always hold true.
In Part 2, I'll talk about how to manage
your signal path in a way that mimics
what the top engineers and producers
do. They often incorporate a workflow that brings together both analog
and digital recording devices and
techniques from every era to produce
recordings that are both truly modern
and timeless. See you then.
Bill Stunt (stunt@recordingmag.com)
is a musician, recording and broadcast
engineer, and educator, living in Ottawa.
RECORDING November 2017

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Table of Contents for the Digital Edition of Recording - November 2017
