Audio Compressor Mixing Mastering Basic.pdf

audio compressor

1. AMY YU
DAW
COMPRESSOR

2. DYNAMIC RANGE
LIMITER

EXPANDERS
COMPRESSOR

GATE

3. WHAT DOES A COMPRESSOR DO?
SIMPLY, A COMPRESSOR IS USED TO COMPRESS A SOUND’S
DYNAMIC RANGE.
That is, to make the louder and quieter parts of the sound’s performance closer to
each other in level.

- It does this in one of two ways. In “downward compression,” The compressor
attenuates the signal when it gets too loud. This is the most common form of
compression.

- In “upward compression,” the compressor boosts signal until it reaches a certain
level. In either case, the dynamic range becomes narrower.

4. COMPRESSOR PARAMETERS
80% OF THE MIX COMES FROM HOW WELL YOUR TRACKS ARE
BALANCED. INVEST PLENTY OF TIME ON THIS STEP!
❏    The threshold essentially activates the compressor according to the
incoming signal. It’s set at a certain level (in dB), and the compressor will
activate when the signal is loud enough to cross this threshold level (downward
compression) or quiet enough to fall below it (upward compression).

❏    How much compression occurs is controlled by the ratio. In a standard
compressor (which is downward), a ratio of x:1 attenuates signal to a level of 1 dB
above the threshold for every x dB it crosses.

6. COMPRESSOR PARAMETERS
❏    The knee affects compression around the threshold. Think of it narrowing or
widening the threshold point, affecting how signal at levels around the threshold
will be compressed.

❏   The attack time (measured in ms) determines how quickly the compressor
reacts once the signal has crossed the threshold. The attack time is the amount
of time the compressor will go from zero compression to full compression
caused by the ratio and threshold.

7. COMPRESSOR PARAMETERS
❏    The signal will eventually drop below the threshold, meaning compression
has to stop. The release time determines how long it takes for the compressor to
go from full compression to zero compression.

❏ To compensate for this, we can use the makeup gain parameter and amplify
the output signal, which will bring those louder parts back to their previous level.
However, when we do this, the entire signal is amplified, boosting the quieter
parts as well. The signal will have a narrower dynamic range,

8. WHY USE A COMPRESSOR?
❏    The sound as a whole will sound “louder” and more present in the mix.
Compression will cause the sound to be less dynamic and organic, but this
added presence can help a sound stand out in the mix.

❏ Additionally, compressors can be used to add color to a sound. Each
compressor is unique, with different analog circuits and digital algorithms being
used. Some compressors have a particular “sound” that engineers like for
different types of instruments (e.g. the Teletronix LA-2A compressor for vocals).

❏ Compressors are also important for controlling the dynamics of live-recorded
instruments and vocals. Hence, compression can help make the level more
consistent.

9. COMPRESSING VOCAL
PRACTICAL TIPS
✦ A fast attack to catch the stray
transient

✦ A quick release so that the
compression doesn’t color the
sound of the singer

✦ A low ratio so that when the
compressor does go on, it
smoothes the vocals without
squashing them
A typical setting might look like
this:

✦ Threshold: –8 dB
✦ Ratio: Between 1.5:1 and 2:1
✦ Attack: <1 ms
✦ Release: About 40 ms
✦ Gain: Adjust so that the output
level matches the input level. You
don’t need to add much gain.

10. COMPRESSING E. GUITAR
PRACTICAL TIPS
The slow attack is what allows the
guitar to have a bit of punch to it.

If you want less punchiness,
shorten the attack slightly. Be
careful though because if you
shorten it too much, you end up
with a mushy sound. (Ahem . . .
we’re not talking romance here. I
mean the guitar has no definition.)
If you do want to use a little
compression to bring the guitar
forward and give it some punch, try
these settings:
✦ Threshold: –1 dB
✦Ratio: Between 2:1 and 3:1
✦ Attack: 25 ms to 30 ms
✦ Release: About 200 ms
✦ Gain: Adjust so that the
output level matches the input
level. You don’t need to add
much gain.

11. COMPRESSING KICK DRUM
For the most part, you can get by with
settings that tame the boom a little and
allow the initial attack to get through. A
sample setting looks like this:

✦ Threshold: –6 dB
✦ Ratio: Between 4:1 and 6:1
✦ Attack: Between 40 ms and 50 ms
✦ Release: Between 200 ms and 300 ms
✦ Gain: Adjust so that the output level
matches the input level. You don’t need
to add much gain.
COMPRESSING SNARE DRUM
Adding compression to the snare drum
is crucial if you want a tight, punchy
sound. The following settings are
common and versatile:

✦ Threshold: –4 dB
✦ Ratio: Between 4:1 and 6:1
✦ Attack: Between 5 ms and 10 ms
✦ Release: Between 125 ms and 175 ms
✦ Gain: Adjust so that the output level
matches the input level. You don’t
need to add much gain