Why AI-generated songs sound thin and quiet (and what fixes it)
People describe the same thing in different words: thin, tinny, small, quiet, 'like it's behind a curtain'. We put numbers to it by measuring 20 Suno WAV downloads against 83 commercial masters. The difference is specific and fixable.
· 6 min read
It is 5 dB quieter
The Suno tracks averaged −15.0 LUFS integrated. Commercial masters in the same styles average around −9 to −10. In a playlist that is the difference between a song that arrives and one that fades in from the back of the room. Listeners do not think 'this needs mastering'. They skip.
Loudness is not the whole story, though — you cannot fix a thin track by turning it up. The tonal balance has to change first, or the limiter just makes the harshness louder.
It is 4–5 dB brighter above 6 kHz
This is the 'AI sheen'. Between 6 and 12 kHz the Suno tracks ran 4.4 dB above the commercial average; from 12 to 20 kHz, 5.0 dB above. That region is where cymbals, sibilance and synthetic 'air' live. For the first thirty seconds it reads as detail. After a minute on earbuds it is fatigue, and it is one of the strongest tells that a track was generated.
The fix is a broad, gentle cut — typically 2–3 dB somewhere around 7–8 kHz — rather than a sharp notch. Then a little saturation puts back a warmer kind of brightness so the track does not go dull.
It is thin between 120 and 350 Hz
The low-mids were 1.6 dB below the commercial average. That band carries the body of a kick drum, the weight of a bass note and the chest of a vocal. On studio headphones it is a subtle difference. On a phone or a laptop, where there is no real bass below 100 Hz, the low-mids are the low end — and a track that is thin there sounds hollow exactly where it is supposed to feel solid.
What was not wrong
Three things we expected to find, and did not:
- No brickwall limiting. True peak averaged −4.2 dBTP — there is plenty of headroom to work with.
- No narrow stereo. Side-to-mid ratio was normal on 18 of 20 tracks.
- No codec damage in the WAVs. High-frequency content extended to roughly 19.9 kHz, the same as commercial releases. (MP3 downloads are a different matter.)
This matters because it changes the prescription. AI tracks do not need 'restoration'. They need the same thing any good mix needs before release: a tonal balance that matches released music, some density, and the right level.
FAQ
Will EQ alone fix it?
EQ fixes the balance but not the density or the level. A finished master also needs saturation or compression to add weight, and a limiter to bring the level up safely.
Does this apply to Udio and other generators?
The measurements are from Suno. Udio and others share the general tendencies — low level, bright top — but the exact numbers differ, which is why a per-track measurement matters more than a preset.
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