Suno WAV vs MP3: which download to use, and what the MP3 actually loses

What the MP3 loses

An MP3 encoder discards what it decides you will not hear. In practice that means content above roughly 16–18 kHz depending on bitrate, and fine detail in dense passages — cymbal decay, reverb tails, the very top of a vocal. On the Suno WAVs we measured, high-frequency content extends to about 19.9 kHz, the same as commercial releases. The MP3 versions stop earlier, with a visible cliff in the spectrum.

You cannot get that back. EQ can boost the region, but it is boosting nothing — you get noise and codec artefacts, not air.

When it matters

• Mastering: always start from the WAV. The master will be re-encoded by every platform; starting from a lossy file means two generations of loss.
• Distribution: distributors want WAV. Some reject MP3 outright.
• Casual sharing: the MP3 is fine. Nobody hears the difference on a phone speaker in a noisy room.

If you only have the MP3

Master it anyway — it will still be quieter and brighter than a commercial release, and those problems are fixable. What matters is that the tool knows it is working from an MP3. MasteringOne measures the high-frequency edge of every file; when it finds a codec cutoff it notes it in the diagnosis and avoids boosting above it, using saturation to add harmonics instead of EQ to boost nothing. The report tells you where the cutoff was.

Then go back to Suno and download the WAV for the final release if you can. The MP3 master is for listening and deciding; the WAV master is for publishing.