Music Craft4 min read

Gain Staging Explained: Headroom, the -18 dBFS Convention, and Where Clipping Really Happens

Gain staging means keeping every level in the range where your processors sound their best. Here are real headroom targets, where digital clipping actually occurs, and why -18 dBFS is the reference.

Gain staging means keeping the signal at a sensible level at every point in the chain. The practical target: average levels around -18 dBFS and peaks around -6 dBFS on individual tracks, with the mix bus peaking near -6 dBFS and no limiter on it. Not because anything breaks otherwise, but because processors sound different at different input levels, and because headroom is the thing you run out of last.

What actually clips

In a modern DAW running 32-bit or 64-bit floating point internally, the mix bus does not clip. You can push a channel to +20 dBFS, pull the fader down afterwards, and the audio is mathematically intact.

Clipping happens at the fixed points:

  • The analogue-to-digital converter on the way in. Once a recorded take clips at the interface, it is clipped permanently.
  • The digital-to-analogue converter on the way out. Your monitors will distort if the master exceeds 0 dBFS, even if the file is fine.
  • File export in a fixed-point format. A 16-bit or 24-bit WAV cannot represent anything above 0 dBFS. Samples above it are truncated.
  • Lossy encoding. MP3 and AAC encoders can produce output several tenths of a dB louder than the source, so a master peaking at exactly 0.0 dBFS will clip after conversion. Leave -1 dBTP of true-peak margin.
  • Any plugin with a fixed internal ceiling, which includes some hardware emulations.

Why -18 dBFS

Analogue consoles had a nominal operating level with roughly 18 to 20 dB of headroom above it before distortion. Plugins that emulate analogue circuits inherit that design: their saturation, transformer modelling and compressor knees are calibrated for signals in that range.

Feed such a plugin a signal peaking at -1 dBFS and you are driving a modelled circuit far past the level it was designed around. Sometimes that is exactly the sound you want. Often it just sounds harsh, and you did not choose it.

Digital-only plugins — clean EQs, linear-phase filters, straightforward digital delays — do not care about input level at all.

Practical targets

StageTargetNote
Recording inputPeaks -12 to -6 dBFSNever touch 0 dBFS; a clipped take is unrecoverable
Individual trackAverage around -18 dBFSUse clip gain or a trim plugin, not the fader
Group and busPeaks around -10 dBFSKeeps bus compressors in range
Mix bus before masteringPeaks around -6 dBFSNo limiter
Final master-1 dBTP true peakLoudness targets are a separate question

How to actually do it

Use clip gain or a trim plugin, not the channel fader. The fader is after most of the chain. If a plugin is receiving too much signal, pulling the fader down does nothing about it. Set the level going into the chain with clip gain or an input trim, and reserve the fader for balance.

Compensate output on every plugin you add. A compressor doing 5 dB of gain reduction with 5 dB of makeup gain leaves the level roughly where it was, so the next plugin sees what you expect. Without this, levels drift upward through the chain and the last processor is being hammered.

Start faders at unity, build up from the loudest element. Set the kick or lead vocal at a sensible level first and balance everything against it, rather than pushing every fader upward in turn until the master clips.

Watch the master with everything soloed off. If the master meter is peaking above -3 dBFS during a mix, you are mixing into a corner. Pull down a group fader, not the master.

The reason it matters

Headroom is optionality. A mix with plenty of it can be made louder, saturated, bus-compressed, or handed to a mastering engineer. A mix already touching 0 dBFS can only be made quieter or squashed. Gain staging is not about correctness — it is about leaving yourself somewhere to go.

Related reading: LUFS and loudness explained, what is mixing, and sample rate and bit depth.

Frequently asked questions

What is the -18 dBFS convention?

Analogue gear was designed around a nominal operating level, and many plugins that model analogue circuits expect signals around -18 dBFS average to hit their sweet spot. Recording and mixing with average levels near -18 dBFS and peaks around -6 dBFS keeps those plugins in the range they were calibrated for.

Does gain staging matter in a 32-bit float DAW?

Internally the mix bus will not distort, so a hot signal is not destroyed. But it still matters, because analogue-modelled plugins behave differently at different input levels, and because anything leaving the DAW as fixed-point audio clips hard above 0 dBFS.

What level should my mix bus peak at before mastering?

Aim for peaks around -6 dBFS with no limiter on the mix bus. That leaves headroom for a mastering engineer or a mastering chain to work with, and prevents inter-sample peaks from clipping on conversion to MP3 or AAC.

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