Frequently asked questions
A few things to know before you lock a track.
- How do I fix BPM drift in a song?
- Drop the song into BPM Lock. It detects every beat, shows you how far the tempo drifts, and time-stretches each beat onto a steady grid at the nearest whole-number BPM, without changing the pitch. You get back an audio file that plays at one steady tempo from the first bar to the last.
- Why does my beatgrid drift on old records?
- The first beat may be offset, the BPM estimate may be wrong, or the performance may change tempo. Check the start, middle and end against a click. A variable beatgrid can follow tempo changes; BPM Lock instead stretches the audio to hold one steady tempo in the exported file.
- Can I set a song to a metronome or click track tempo?
- Yes. That is exactly what BPM Lock does: it locks every beat of the song to a metronome-steady grid at an integer BPM. You can audition the original audio against a click track before rendering to confirm the grid is right.
- Does fixing the tempo change the pitch of the song?
- BPM Lock uses pitch-preserving time stretching. The timing changes, while the pitch is preserved. Stretching can still produce audible artifacts, so compare the original and corrected versions before exporting.
- How is this different from warping in a DAW like Ableton?
- Ableton and other DAWs can warp audio and export a corrected file too. BPM Lock focuses on one job: correcting tempo drift at the detected whole-number BPM, with beat detection, manual grid correction and export in your browser. Your audio is not uploaded.
- Can I get an acapella that stays in time?
- BPM Lock does not split stems itself, but it fixes the thing that makes a split acapella unusable. Run the locked file through your stem splitter instead of the original: the whole track is already on a constant grid, so the vocal comes out in time from the first bar and sits over a loop or an instrumental at the same BPM without warping. Split the drifting original and the acapella drifts with it.
- What music does BPM drift correction work best on?
- Anything played by humans without a click: old funk, soul and disco records, live recordings, classic rock, hand-played house. Grid-quantized modern tracks pass through nearly untouched.
- Is my song uploaded to a server?
- No. Beat detection, time stretching and encoding all run inside your browser. The audio never leaves your machine, so unreleased promos and white labels stay private.
Got a track that will not stay in time?
Your audio stays in your browser. No account needed.