Fig. 1. Mixes like this are no fun to master, and they can’t be mastered to reach their full potential.
If there’s one thing a mastering engineer doesn’t want
to see, it’s a mix that looks more like a sausage than
audio (Figure 1). This is usually due to someone who
straps a maximizer-type dynamics processor across
the master mix bus for a “loud” sound, without realizing
that it ties the mastering engineer’s hands (who
likely has better tools for making audio loud anyway).
However, lately I’ve been getting something more disturbing:
mixes that look a lot like Figure 1, but upon
closer examination, have clipping issues.
Fig. 2. The peaks circled in red are clipped.
Referring to Figure 2, you can see the waveforms
are “flat-topped,” which causes clipping distortion. One
reason this happens is because the mix engineer doesn’t
realize that with digital, “going into the red” almost
invariably generates clipping, so they don’t get too
bothered when the overload light goes on. But another
is personal taste: Some people like the sound of digital
distortion, and figure a little clipping won’t hurt. But
when this file goes to the mastering engineer, remember
that mastering puts a sort of magnifying glass up to
the audio. Once digital distortion is part of a mix,
there’s almost nothing the mastering engineer can do
to remove it. The end result is a sort of fuzzy, harsh
quality that robs definition and causes ear fatigue.
Fig. 3. The peaks circled in red have been severely compressed, but still sound better than being clipped.
Now consider Figure 3. This also shows a mix that
has virtually no headroom, but it’s due to excessive
amounts of compression and limiting, not clipping. The
waveform peaks aren’t flat-topped, but simply reduced
in level. Although this file is still far from ideal from a
mastering standpoint, and won’t let mastering reach
its full potential, it’s better than clipping distortion.
Let the Mastering Engineer
The solution is simple: Don’t use any processors
across the stereo bus (like maximizers), and set levels
so there’s plenty of headroom when mixing—I generally
don’t let peaks go much above –10 to –6dB in
my mixes. Mastering can always make it loud.
Some engineers balk at this, saying they like to
push the output because it’s part of their sound, and
they like a squashed effect. In that case, sure, throw a
maximizer across the stereo out, and mix away—but
bypass it before exporting the final mix. Then include
a note to the mastering engineer saying you want a
really loud, squashed mix; they’ll do their best to give
you what you want.
As a mix engineer, get the mix and the balance
right—but don’t mix too hot and introduce distortion,
or you’ll just end up with a frustrated mastering
engineer, and a recording that won’t sound
anywhere near as good as it possibly could when