Audio Mixing & Mastering

Sound design (an earlier lesson) decides what audio elements exist and roughly where. Mixing is the technical process of balancing their levels, tone, and dynamics so the result sounds professional on every playback system, from cinema speakers to a phone held at arm's length.

Understanding dB and Headroom

Audio levels are measured in decibels (dB), typically shown as dBFS (decibels relative to full scale) in a digital audio meter, where 0dB is the absolute ceiling before distortion. Never let your mix touch 0dB — leave headroom, a buffer between your loudest peak and the ceiling, so transient sounds (a sudden clap, a hard consonant) don't clip. A good target peak for a full mix is around -6dB to -3dB, not 0dB.

The Essential Sound Panel

Window > Essential Sound is the fastest path to a solid mix. Select a clip, tag it by type (Dialogue, Music, SFX, or Ambience), and the panel exposes purpose-built controls for that type:

• Dialogue — "Auto-Match" volume across clips recorded at different levels, "Reduce Noise" for background hiss, "Reduce Reverb" for room echo, and a dynamics/loudness target
• Music — the "Duck Against" feature covered earlier, plus overall loop and fade controls
• SFX — basic gain and pan
• Ambience — designed for consistent background beds

Essential Sound's automated tools are a strong starting point, but for detailed problems (an inconsistent breath sound, a specific frequency clash), the full Audio Track Mixer and individual effects give more control.

EQ Basics

Equalization (EQ) shapes a sound's frequency content. Applied via the Parametric Equalizer effect, or through Essential Sound's dialogue preset:

• High-pass filter — cuts everything below a set frequency (commonly 80-100Hz for dialogue) to remove rumble, handling noise, and AC hum that carries no useful information
• De-essing — reduces harsh "s" and "t" sounds in dialogue, common with close-mic'd voice
• Presence boost — a slight boost around 3-6kHz on dialogue improves clarity and intelligibility, especially on small speakers
• Cutting vs. boosting — as a general habit, cutting a problem frequency sounds more natural than boosting everything else around it

Compression

A compressor reduces the volume of the loudest parts of a signal, narrowing the gap between quiet and loud moments (dynamic range). For dialogue, mild compression keeps volume more consistent so viewers aren't reaching for the volume knob between a whisper and a shout. Key controls:

• Threshold — the level above which compression starts acting
• Ratio — how strongly volume is reduced above the threshold (e.g., 3:1 means 3dB over threshold becomes 1dB of actual increase)
• Attack / Release — how quickly compression engages and disengages

Start subtle — a ratio around 2:1 to 4:1 with a moderate threshold on dialogue is usually enough. Over-compressed audio sounds flat and fatiguing.

Loudness Standards

Platforms increasingly normalize loudness automatically, which means an aggressively loud mix doesn't actually sound louder on playback — it just loses dynamic range for nothing. Target integrated loudness (measured in LUFS — Loudness Units Full Scale) appropriate to your platform:

Check integrated loudness via the Loudness Radar effect (apply to your master/output, or use Audio Track Mixer's loudness metering) rather than guessing from peak levels alone — LUFS measures perceived loudness over time, which correlates much better with how loud a viewer actually experiences your video.

Final Mix Checklist

Before exporting, verify:

• No clipping — check peak meters stay below 0dB throughout, especially on the loudest moment
• Dialogue is consistently intelligible across every clip and camera angle used
• Music and SFX sit under dialogue, not fighting it
• Integrated loudness roughly matches your target platform
• The mix has been checked on at least two playback systems (headphones and built-in speakers, minimum)