Clipping and true peak: how to find and fix them

What digital clipping is

Digital audio has a ceiling — 0 dBFS. Anything that tries to go above it is cut off: the top of the wave turns into a flat line. That shape contains harmonics that weren’t in the original sound, which is why clipping is heard as dry crackle, “sand” on the vocal or crunch on the drums.

It’s important to tell accidental clipping from deliberate clipping. In trap, EDM and some rock genres a soft clipper is used as a tool: it rounds off the peaks gently and adds density. The trouble starts when clipping happens by accident — on export, on the master bus or because the file was normalized to zero.

The Stream-Q analysis counts a clipped section wherever three or more consecutive samples sit at the maximum level, and shows when the first one happens. Ten or more clipped sections is a serious problem the streamer will know about before pressing Play.

What true peak and inter-sample peaks are

A digital file is a set of points — samples. On playback, the digital-to-analog converter joins them with a smooth curve, and between two samples that curve can rise above either of them. That’s an inter-sample peak. A regular DAW meter only looks at the samples and may show, say, −0.1 dBFS, while the real reconstructed signal reaches +0.8 dBTP.

A true peak meter oversamples the signal at least four times and finds these hidden peaks. The unit is dBTP (decibels true peak).

How to find clipping and peaks

1. An analyzer. Upload the file to the true peak check or the full track analyzer: it shows true peak per channel, the number of clipped sections and when they happen.
2. A true peak meter in your DAW. Put it last on the master bus. Many mastering limiters and loudness meters show true peak as a separate value.
3. The waveform. Zoom in on a loud hit: flat tops several samples long are clipping.
4. Your ears. Listen to the loud parts on good headphones at a moderate level. Crackle on the kick, on sibilants and at the ends of vocal phrases are common signs.

Check the exported file, not the project. Inside the project part of the processing runs in 32-bit floating point, where going over zero isn’t clipped. Clipping happens at the moment of export to 16 or 24 bits.

Where overload comes from

• A master bus with no headroom. The sum of the tracks goes above zero, and there’s no limiter or it isn’t last in the chain.
• A limiter without True Peak mode. A 0 dB sample ceiling doesn’t protect against inter-sample peaks.
• Normalization on export. A “normalize” option raises the file so its peak just touches zero — and the inter-sample peaks go above it.
• Plugins after the limiter. An EQ or an “enhancer” after the limiter can push the peaks back up.
• A master that’s too loud. The harder the limiter works, the more distortion and inter-sample peaks you get.
• Conversion from MP3. A decoded MP3 can contain peaks above zero that get clipped when saved as WAV.

How to fix it, step by step

1. Open the project, not the finished WAV. A clipped wave top can’t be restored: dedicated de-clippers soften the problem but don’t bring back the original signal.
2. Check the master bus before the limiter. If the sum is already above zero, lower the overall level of the tracks or put a gain plugin before the master chain.
3. Turn on the limiter’s True Peak mode (some limiters call it ISP or “inter-sample peaks”).
4. Set the ceiling (output) to −1 dB. For masters louder than −10 LUFS, −2 dB is safer.
5. Reduce the limiter’s input gain if it constantly takes off more than 3–4 dB. The LUFS loudness will drop slightly, but the hits will get their attack back.
6. Remove every plugin after the limiter except the meter and, when exporting to 16 bits, dither.
7. Export to 24-bit WAV without normalization and check the file again.

Check phase and mono while you’re at it

Another technical problem the analyzer finds along with peaks is the channels being out of phase. If the correlation is below zero, part of the sound disappears when summed to mono (a phone, a speaker, some club systems). Stream-Q flags a loudness drop of more than 3 dB in mono. The usual causes are stereo wideners on the bass and duplicated, offset tracks. The fix is to keep the low end in mono and to check the master with a mono button on the master bus.

Frequently asked questions

If I export to 32-bit float, will there be no overload? Inside such a file, values above zero really are kept. But the platform, the distributor or the player will still convert the file to a fixed bit depth or compress it with a codec — and the clipping will happen on their side, out of your control. For delivery, prepare a file that stays within −1 dBTP.

Do I need to watch true peak in a demo? Yes, if the demo is played on a stream: the broadcast compresses the sound with one more codec, and the overload becomes more noticeable. A demo can be at any reasonable loudness, but it shouldn’t clip.

Why do different meters show different true peak values? They oversample the signal differently, with different ratios and filters. A difference of a few tenths of a decibel is normal. If it’s bigger, make sure you’re comparing the same file, not the project and the export.

Can I master with a −0.1 dB ceiling, as people used to for CD? For a CD, which isn’t re-encoded, that worked. For streaming, a tenth of a decibel of headroom isn’t enough — the codec will almost certainly create peaks above zero.

Before sending to a stream or a distributor

• Zero clipped sections in the exported file.
• True peak no higher than −1 dBTP on both channels.
• Loudness in a sensible range — see the article on loudness for streaming platforms.
• The file is an export from the project, not a conversion from MP3.