The two first options are realized within the the MIDI tempo track. def-tempo must always be given before compilation.
Single global tempo for all instruments
(def-tempo 120)
(compile-instrument-p "ccl;output:" "overlaps"
piano1
piano2
)
Global tempo curve for all instruments
Use def-zone to define a tempo change points, and tempo pattern with def-tempo.
(def-zone
tempo '(1/1 1/1 1/1 1/1 1/1 1/1)
piano1 '(2/1 2/1 1/1 1/1)
piano2 '(2/1 2/1 1/1 1/1)
)
(def-tempo '(120 140 200 60))
Tempo pattern can have less, equal or more elements than there are tempo change points. If there are less, then this pattern is repeated for all tempo changes. All instruments will use this tempo. See def-signature.
Individual tempos for each instruments
This is a bit tricky and can be fun or lead into misery. The tempo calculation is done internally changing the length values of each instrument. Each istruments tempo pattern is bound to a global tempo base. To get the right output you probably have to move the track to a sequencer and set manually the tempo to 120.
When using multiple tempo do not expect them to keep in syncronicity with each other. Depending on the sequencer tick resolution, coercing errors may corrupt the rhytmics as when scaling a bit-mapped image. Each tempo is relative to the tempo-base value. Here the tempo base is set to 121.
