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
January 5, 2022 |