Why your Suno song sounds muffled, and what actually fixes it

Many people describe Suno v6 output as muffled or flat, with buried vocals and a weak top end. Measurements of matched v5.5 and v6 songs found v6 carries more energy below 120 Hz and a noisier top octave.

Some of that is in the mix balance, which mastering can adjust. Some of it is baked into how the song was generated, which no mastering can change.

Overall loudness: about −14 LUFS with peaks under −1 dB for Spotify.

Boomy or rumbling low end: tighten it and keep the bass mono, rather than cutting it with a high-pass filter.

Muddy build-up around 200–500 Hz: a small cut of 1–3 dB.

Buried vocals: EQ lifts everything in the vocal range. Edit that section in Suno, or rebalance stems.

A missing top end: boosting the highs mostly raises noise.

Shimmer, warbling or garbled words: regenerate or edit that part in Suno.

Squashed dynamics: once the loud and quiet parts are flattened, a master can't bring them back.

1. Load the song in Mastering. You get a verdict that labels each problem as fixable here or not.

2. For anything mastering can't fix, open Fix a Track. It writes a plain-language edit you can paste into Suno v6, which changes one section and keeps the rest.

3. Master what's left with the Suno v6 starter preset, then export at −14 LUFS.