Audio Mixing Bootcamp

Notes from a LinkedIn course.

Prepping

• make a copy for every mix version (optional)
• remove empty tracks
• remove / deactivate unused tracks
• group tracks together (synchronous volume changes, mute etc.)
• rename tracks with a descriptive and short names
• color code tracks (groups)
• Aux is for subgroups (applying effects to a set of tracks)
  • saves system resources
• A bus is just an audio pipe, a way of manipulating streams of audio in a structured manner
• An insert is an input; e.g. in an aux channel, inserts are identifying sources of audio

Reverb

• pre-delay: onset of the effect after the signal
  • ~20 ms
• decay: short 1.2 s, long 2 s
• usually in stereo

Delay

• usually in mono
• delay 175 ms is favourite of McCartney
• feedback: a number of repeat

Basics of Mixing

• Groove is the pulse of the song.
• It doesn’t have to be perfect, it’s created by tension against even time.
• Doesn’t need to follow drums.
• What instruments provide the pulse?
• Find the most important element

Avoid

• no contrast
• no focal point
• noisy
• lacking clarity and punch
• sound distant
• inconsistency of levels
• dull and uninteresting sounds

Building Mix

• Mix bus level will get louder with every instrument entrance (~3 dB)
• Start with mix bus at –10 dB
• The sound of every drum will change when a new drum or cymbal is added.
• Kick outer mic should be barely audible

Panning

• We usually don’t pan drums (snares) and bass, they loose some power.
• Pan something to stay out of way.
• Background voices are good a bit to left and right, not fully.
• Panning 20–30 to left and right for spaciousness.
• Drums are panned 90% from audience perspective.
• Hi-hat panned right.
• More panning → less powerful.
• Avoid pseudo-stereo (recorded, simulated stereo).
  • Panning everything hard left and right will mingle everything.
  • Better pan stereo tracks across the space spectrum.
• Reverb can add stereo effect (spaciousness).

Compression

• Automated level control.
• Controls:
  • Ratio: How much the level increase according to the input level. 4:1 means every 4 dB input goes to 1 dB output.
  • Threshold: Signal level when the compression starts to be applied.
  • Attack: How fast/slow compressor reacts on the beginning of amplitude.
  • Release: dtto on the end of amplitude.
  • Gain (output): compensation for the attenuated compressed signal
  • Knee: onset of compressor
• Side-chain is linked to EQ or other filters or tracks (in el. music).
• Compressor is usually before EQ
• Applied on tracks with variations of dynamics.
• Compressor should “breathe” with the track.
• Compressing vocal is the way to keep vocal audible and comprehensive together with the band; opposite to the pop songs where vocal is above the rest
• Ratio up to 10:1 is for correcting dynamics, higher ratio creates a specific effect: limiting.
• The New York compression trick (parallel compression): second compressor on a group set to barely audible level together with the original group

Noise gates (expander), de-essers

• The opposite of compressor
• A special type of compressor: de-esser – compressor on some frequency interval

EQ

• number of bands
• gain, frequency, queue (bandwidth)
• subtractive equalization (technique)
  • attenuating instead of boosting
  • phase-shift is made as a deformation when boosting
  • start with HMF and find the position best improving the track
  • or boost and find the worst place and then subtract
• works especially wel in 200–600 Hz (lot of mic proximity effect) and 2k–4k (presence boost)
• boosts: point 1k–5k, sparkle 5k–10k, air 10k–15k; just 1–2 dB
• juggling frequencies (technique)
  • e.g. two similar instruments
  • boost frequencies on one and attenuate on the other
• high pass filter for cleaning up recordings
• principles:
  • if it sounds muddy, attenuate at 250 Hz
  • if it sounds honky, attenuate at 500 Hz
  • cut or attenuate to add clarity
  • boost to make things sound different
  • use narrow bandwidth 6–10 when cutting and 0.5–2 when boosting