Reaper: Tempo Mapping

Snap to grid is Alt + S - you will need this often.

1. Project Settings (🛈 in toolbar or Alt + Enter).
2. [Project Settings] Timebase for items/envelopes/markers: Time
3. For each MIDI item (if any):
   1. Right click > Source properties…
   2. [MIDI item properties] Ignore project tempo: checked
4. If there are multiple items, group them so the all move together.
5. Make sure the audio starts after bar 2.
6. View > Tempo envelope
7. Turn on Grid & Snap.
8. [Snap/Grid Settings] Show grid, line spacing: checked, 1, 1/2 or 1/4, depending on how accurate you want it.

1. Find a section with 2 or 3 bars with good transients.
2. Snap off, move the item so that the first transient aligns with any beat.
3. Snap on, create a selection starting at the first transient.
4. Snap off, adjust the end of the selection to beginning of a bar. Make sure you cover 2 or 3 bars and all the beats in them.
5. Menu > Insert > Measure from time selection (new time signature)…
6. [Edit Time Signature] Set bars, OK.
7. This will create a tempo marker with the correct tempo. Double click it and copy the tempo.
8. Double click the very first tempo marker and set its tempo. The media item will move.
9. Alt + click to remove the other two tempo markers.
10. Realign the media item. Make sure aligns with a bar and has the lead in bar as you want it.

1. Shift + click on bar line in Tempo envelope to create marker.
   1. Ctrl + drag on tempo at top of marker and move it to beginning of transient.
2. Adjust one marker without affecting everything to the right:
   1. Ctrl + Alt + drag on tempo at top of marker.