Tempo mapping with SWS
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About
This is documentation for the Breeders (BR) actions and dialogs regarding tempo and tempo-mapping. You need to have the latest beta of SWS extension installed.
All coding by breeder. Concepts by Breeder and G-Sun.
Introduction
Let's say you have a mono/stereo/multi-track recorded, by yourself or by someone else. Then, in Reaper, you want to align the tempo-grid to allow yourself to sync and quantise midi and/or audio to the original music. You then need to find the tempo of the original song.
If it was recorded to a fixed tempo, then it's just a matter of finding that tempo. However if it was not, then you need to tempo-map the song. That is what this page is about.
Tips: Use alt + t to show your master track with tempo envelope.
Where to find them
Please open the action dialog (Shift + ?), and type in "SWS/BR" or "BR". Select the appropriate action. You'll often find the actions easier to use if you assign a shortcut to them, or make some buttons for your toolbar (see REAPER User Guide).
(A) Adding markers
The first thing you'll have to do is putting markers on all beats. Choose the beat-frequency of your taste/need, typical 1/1, 1/4 or 1/8.
Using your pc-keyboard
Then, play the song from start to finish tapping M on your pc-keyboard (inserting a marker on each place).
Play the song through a second time. See if all markers are on right place, and that no-one is missing. Edit/add/delete markers until satisfied.
You'll then have something like this:
Using midi
Or, you can use your midi-keyboard or other midi-device (like drum-triggers). Arm a track for your input, and tap a note on every beat.
This is convenient for giving a sound to each tap.
It may look something like this:
Then run the action "sws/br: Create project markers from notes in selected midi items".
(B) Convert markers to tempo
When you're satisfied with the placement of your markers, choose the action "SWS/BR: Convert project markers to tempo.."
Important: Items timebase should be set to to TIME so items don`t strech or get moved during mapping. When opening dialog, you will get notified to change timebase if it`s already not set
Then a dialog will open:
- Markers per measure: For 1/1 enter 1, for 1/4 enter 4 or for 1/8 enter 8.
- Time signature: Set the correct time-signature for your project or time-selection. (Tips: In some cases 1/4 or 1/8 can be useful)
- Create gradual tempo changes: This will output linear shaped points, and twice as many.
- Remove project markers: Choose (unchecked is recommended)
- Convert only time-selection: If a time-selection is set, you can choose to only convert this time-section (Necessary for songs with different time-signatures)
- Split middle point by: If you've chosen "Create gradual tempo changes" above, this option will appear. It allows you to split the middle point and choose the length of the middle line. The purpose is a smoother tempo-line. You can choose whatever fraction you like (Format 1/3; 0,3 or 0.3). 1/3 or 1/2 is recommended.
Notes
Square output
For our example (and good starting-point if you're unsure), let's use these settings:
This will output something like this:
Notice:
- First marker will have a time-signature setting and have "allow partially measure before this marker" set.
- Last marker will have no tempo-marker.
Linear output
For the same project markers, choosing linear output will give this:
Notice:
- Doubling of the points are needed to make linear transitions correct.
- In this case, the first point is set to linear manually prior to running this action.
Linear output, split middle point
For the same project markers, choosing linear output split middle points checked (here 1/3), will give this:
Notice:
- The number of points is tripled compared to square output
(C) Tweaking tempo
Please see sub-page: Tweaking tempo
Other tools
Other methods
There are other methods of doing tempo-mapping, see:
