How to: fix a track that sounds off
Everything else in the mix locks, but one track is wrong. That is almost always the track's data, not where you placed it — its BPM, its beat grid, or its "1".
First work out which kind of wrong, because each has a different fix. Turn on the metronome (K) and play the track through.
| What you hear | What's wrong | Fix |
|---|---|---|
| Starts fine, drifts off gradually through the song | BPM is slightly wrong | Fix BPM |
| Never settles — wanders in and out even early on | The track genuinely drifts | AI Flex |
| Tight, but comes in on the wrong beat of the bar | The "1" is wrong | Set Downbeat |
| Off by a hair at one seam only | Phase | ⇄ Sync |
The drift test
A small BPM error produces a slow, continuous slide — it sounds fine at the start and is obviously wrong two minutes later. That is the giveaway.
It doesn't take much. A track stored as 122.5 that is really 123.0 is only 0.4% out, and that is one full beat of drift every two minutes. Half a BPM is enough to ruin a long blend.
The fix, in order
Do these on the offending track, then rebuild. Order matters — tempo first, because the "1" is meaningless if the tempo is wrong.
- Track tab → Fix BPM — set the true tempo (e.g. 123.0, not 122.5).
- AI Flex on — only if the track genuinely wanders. Flex warps a drifting grid onto a steady
tempo. On a track that's merely mis-labelled, the BPM fix alone is enough and Flex is unnecessary work.
- Set Downbeat — by ear, so the "1" is yours. Worth doing whenever the detector was unsure (see
below).
- ↻ Rebuild mix — the prepare cache keys off grid edits, so it re-renders clean automatically.
Then listen again:
- drift gone, but it enters on the wrong beat → it's the "1". Nudge ◀ ▶, or set the downbeat again.
- still drifting → the BPM is still wrong, or the track needs Flex.
When the "1" is a guess
The engine records how confident it was about each downbeat. It no longer nags you about it — that was a dialog on nearly every track and your ear is faster — but the number is still there and it is worth knowing when a seam sounds bad.
A confidence around 0.1 means the detector effectively flipped a coin. At that point the bar phase may be wrong even at a perfect tempo, and setting the downbeat by ear is the only real fix.
If one track in a set had an untrusted "1", others probably do too. Fixing them together saves rebuilding the mix repeatedly.
What ⇄ Sync will and won't do
Sync slides each track at most half a beat so its beats land on the grid. That cap is deliberate: it can tighten a track onto the beat it is already nearest, and can never jump it onto the wrong beat or shift its bars.
So "Sync says beat-locked but it still sounds off" is a meaningful message, not a failure — it means the error is bigger than half a beat, which makes it a placement problem or wrong grid data. That's this guide, not Sync.
Notes
- A mix built before you fix a track keeps the old grid until you rebuild it.
- Fixing BPM or a downbeat invalidates that set's prepared cache on purpose, so the next open
re-prepares. That's slower once, then cached again.
- The metronome (K) is the fastest instrument you have here: if the click and the kick disagree,
the grid is wrong, and you'll know inside a bar.