Distorted Master? Audio Mastering Fixes
If your master sounds distorted, the cause is almost always something that happened during audio mastering, and the free Audio Master tool gives you enough readouts to find which one. There are four usual suspects: a limiter pushed too hard, inter-sample peaks going over after conversion, plain clipping, and lossy-codec artifacts that show up only after you upload. Each one sounds a little different and has its own fix. Everything below runs in your browser, and your audio never leaves your device.
The short answer: why does my master sound distorted after audio mastering?
Distortion in a master means the waveform got changed in a way you didn't ask for. Mastering causes that in four ways:
- Over-limiting. The limiter is grabbing so many peaks, so hard, that the transients flatten and the track starts to crackle and pump.
- True-peak overs. The samples stay below 0 dBFS, but the waveform rebuilt between them goes over. A DAC or an encoder then clips it.
- Clipping. Peaks go past full scale somewhere in the chain, often before the master even starts.
- Codec artifacts. The file sounds fine locally and turns swirly or crunchy once a platform re-encodes it to AAC, Opus, or MP3.
Start by working out which one you have. The fix for over-limiting is the opposite of the fix for a noisy source.
Step 1: Rule out the mix first
Before you touch any mastering setting, listen to the unmastered mixdown on its own. In Audio Master, the level-matched A/B plays the original and the mastered version at the same loudness, so switching to "Hearing: Original" tells you whether the crunch was already there.
If the original distorts, mastering can't fix it. It will only make it louder. The usual causes are a clipped bus, an overdriven plugin, or a bounce that hit 0 dBFS. Check the "Original" readout: a peak sitting right at 0.0 dB on a mixdown is a warning sign. Go back to the mix, pull the master fader down, and bounce again. What Is Audio Clipping (and How to Avoid It)? explains how to spot it, and What Is Audio Headroom? covers how much room to leave.
Step 2: Back off an over-driven limiter
If the original sounds clean and the mastered version doesn't, the limiter is the first place to look. A limiter gets you loudness by pulling down peaks. Ask for a lot more loudness and it has to pull them down all the time, so kick and snare lose their attack, sustained notes start to fuzz, and the whole mix breathes with the drums. What Is a Limiter in Audio? covers how that works.
In Audio Master, the Loudness target sets how hard the limiter works. The tool works out the gain needed to reach the target and drives the signal into an output limiter that holds peaks at about −1 dB. The louder the target, the harder that limiter has to work.
To back off:
- Pick a quieter Loudness target. Moving from Club / Loud (−9) to Spotify (−14) or Apple Music (−16) cuts several dB of gain going into the limiter. That one change often clears up a crunchy master.
- Lower the Compression step. Aggressive compression plus a loud target stacks two kinds of gain reduction. Try Firm or Gentle, or Off if the mix was already controlled.
- Tame the low end. A big sub eats headroom, so the limiter clamps down on every kick. Raise the Rumble filter, or pull the Low 100Hz EQ band down a dB or two.
- Compare again with the A/B. Since both sides play at the same loudness, you're judging texture, not volume.
Streaming services turn loud masters down anyway. Spotify's default reference is −14 LUFS, so a −9 LUFS master gets played back quieter and keeps its distortion. How Streaming Loudness Normalization Works covers this, and What LUFS Should I Master To? lists targets by platform.
Step 3: Catch inter-sample (true-peak) overs
A digital file stores samples, but what you hear is a continuous waveform rebuilt from them. Between two samples just under 0 dBFS, that rebuilt wave can go above 0. This is an inter-sample peak, and a converter or encoder that doesn't expect it will clip it. True peak, measured in dBTP, is the level that includes these in-between overs. What Is True Peak? goes into more detail.
A limiter that only watches samples can let these through. The limiter in Audio Master is a fast, high-ratio compressor, not a true-peak limiter, and the Mastered readout after export shows sample peak, not true peak.
To check true peak, drop the exported master into the Volume Booster and read "Peak before." It measures true peak (an oversampled estimate). If it reads above −1 dBTP, you have inter-sample overs that a lossy encode could turn into audible clicks. Fix it by lowering the Loudness target a step and exporting again. The Volume Booster only adds gain, so it won't pull an over-ceiling peak down. For a finished file that's already over, use the peak mode in the Volume Normalizer with a −1 dBTP peak target, which turns the whole file down by the amount needed.
Step 4: Where to set the ceiling
The ceiling is the highest level your limiter lets through. For streaming, the clearest published spec is Spotify's: keep true peak below −1 dBTP. Other platforms don't publish a number, so −1 dBTP has become the common convention.
For loud masters, go lower. Spotify itself advises keeping true peak below −2 dBTP if your master is louder than −14 LUFS, because lossy encoding can raise peaks. Some engineers also use −1.5 or −2 dBTP for low-bitrate encodes. For broadcast, EBU R128 pairs a −23 LUFS target with a −1 dBTP maximum.
In Audio Master the output limiter's ceiling is fixed at about −1 dB, and you don't set it directly. If you need more margin, choose a quieter Loudness target, or turn the finished file down afterward with the Volume Normalizer's peak mode. Compressor vs Limiter: What's the Difference explains why the limiter is the stage that owns the ceiling.
Step 5: Diagnose lossy-codec artifacts after upload
If the WAV sounds clean but the version on a streaming platform or social app sounds smeared, swirly, or crunchy in the cymbals, the platform's encoder is probably at fault. Lossy codecs throw away detail they expect you won't hear. A master that's very loud, very bright, or peaking right at 0 gives the encoder less to work with and makes overs more likely.
What helps:
- Upload a lossless file. Export WAV from Audio Master (it's the default) so the platform encodes once from clean source, not from an MP3 that's already been encoded.
- Leave true-peak margin. −1 dBTP or lower, per Step 4.
- Ease off the top end. A heavy High 8kHz boost gives the encoder lots of hard-to-code content. A dB less often cleans up the sizzle.
- Test before you publish. Export an MP3 or Opus copy yourself and compare it with the WAV. If your own encode sounds wrong, the platform's will too. Bitrate vs Sample Rate explains what those settings change.
Which fix for which symptom
| Symptom | Likely cause | Fix |
|---|---|---|
| Original already crunchy | Clipping in the mix | Re-bounce the mix with headroom |
| Fine at −14, crunchy at −9 | Over-limiting | Quieter Loudness target, lower Compression |
| Pumping on every kick | Low end hitting the limiter | Rumble filter, cut Low 100Hz |
| True peak above −1 dBTP | Inter-sample overs | Lower target or cap at −1 dBTP |
| Clean WAV, harsh after upload | Codec artifacts | Upload WAV, keep true-peak margin |
If the problem is the opposite and your master sounds clean but too quiet, see Master Too Quiet? Fixes Beyond a Volume Booster. For the whole process from mixdown to export, read How to Master a Song Online for Free, or browse the how-to guides.
Frequently asked questions
Why does my master sound distorted when my mix didn't?
The most common cause is over-limiting. A loud loudness target forces the limiter to pull down peaks constantly, which flattens transients and adds audible crunch. Choosing a quieter target, such as −14 LUFS instead of −9, and easing off compression usually clears it up.
What is a true-peak over?
It's a peak that goes above 0 dBFS between samples, even though every stored sample is below it. When the file is played back or encoded to a lossy format, the rebuilt waveform can clip. Measuring true peak in dBTP catches these overs, which a sample-peak meter misses.
Where should I set my limiter ceiling?
For streaming, −1 dBTP is the common choice, and it matches Spotify's published recommendation. For masters louder than −14 LUFS, Spotify advises staying below −2 dBTP. For broadcast under EBU R128, the maximum true peak is −1 dBTP alongside a −23 LUFS target.
Why does my master sound fine as a WAV but distorted on streaming?
Streaming platforms re-encode your upload to a lossy format. A very loud master with little true-peak margin or a heavy top end can pick up artifacts or clip in that encode. Upload a lossless WAV, keep true peak at or below −1 dBTP, and test an encoded copy yourself before publishing.
Can mastering fix distortion that's already in my mix?
No. Mastering works on the finished stereo file, so clipping or overdrive baked into the mix stays there and usually gets louder. Fix it at the mix stage by lowering the level going into the master bus, then bounce again with headroom before you master.