How to sync a beat or another track to a song

1. Set the project BPM to your song’s BPM. For the song clip, right-click the Time knob under Time stretching → Reset so it keeps its original speed.
2. Double-click the beat or other track. Under Time stretching, set Mode → Stretch to keep its pitch.
3. Open that clip’s waveform menu → Fit to tempo → Type in BPM. Enter that clip’s original BPM, not the song’s BPM.
4. Move the clip so its first beat lands on the song’s first beat. Play them together and check again further into the song.

FL Studio reference ↗

1. Set the project BPM to the song’s BPM. Double-click the song clip and turn Warp off.
2. Double-click the other track and turn Warp on. Find its first beat, right-click it → Set 1.1.1 Here.
3. Right-click that marker → Warp From Here. Check the detected Seg. BPM against the recording’s original BPM.
4. Choose Beats for a drum loop or Complex / Complex Pro for a whole song.
5. Move the clip’s first beat onto the song’s first beat. Play both; if a later beat misses the grid, correct that beat with a Warp Marker.

Ableton Live reference ↗

1. Set the project BPM to the song’s BPM. Choose Keep in the Smart Tempo menu; leave Flex & Follow off on the song region.
2. Double-click the other audio region → Smart Tempo. Check its detected BPM and first beat; use Edit → Analyze Tempo if needed.
3. Right-click that region in the Tracks area → Tempo → Apply Project Tempo to Region and Downbeat.
4. Move the region to the song’s matching first beat. Play both and check a later section too.

Logic Pro reference ↗

1. Set the project BPM to your song’s BPM before importing. Import the song at its original speed: choose Do not stretch media if asked.
2. Drag the beat or other recording onto a separate track. REAPER can read its original BPM from tempo metadata or a BPM-labelled filename.
3. In the import dialog, choose Stretch media to project tempo → OK.
4. Move its first beat onto the song’s first beat. Play both and check a later section.

REAPER reference ↗

1. Set the project BPM to the song’s BPM. Keep Musical Mode off for the song.
2. Double-click the other recording to open the Sample Editor. Set its Tempo to the recording’s original BPM. For a neatly cut loop, entering its correct bars and beats also calculates this.
3. Turn on Musical Mode for that recording. It now follows the project tempo.
4. Move its first beat onto the song’s first beat. Play both and check a later section.

Cubase reference ↗

1. Select the song track → Inspector → Tempo → Don’t Follow. Set the session tempo to the song’s BPM.
2. Select the other audio event. In the Inspector, enter its original BPM in File Tempo.
3. For that track, set Tempo → Timestretch. Choose Drums for a drum loop or Sound for a mixed recording.
4. Move its first beat onto the song’s first beat. Play both and check a later section.

Studio One / Studio Pro reference ↗