Hi there,

even though the trumpet part is slowing down, there is accelerando expression and dots on the score, that’s clearly because of the tempo change at 9th beat. How can we get rid of contradictory accel. expression?


In this case, actually, the accelerando is accurate: it refers to the overall acceleration of the Session from 60 to 100 (due to s.set_tempo_target(100, 9)).

Within that acceleration, the trumpet is slowing to half speed (due to clock.set_rate_target(0.5, 6, duration_units="time", metric_phase_target=0), which is expressed not through a tempo change, but through a change from eighth notes to quarter notes. The net effect of note values slowing to half speed and the overall tempo going from 60 to 100 is actually a slowing down of the trumpet part, because 60 to 100 is less than double speed.

Totally understandable that this is confusing… The basic thing to understand is that an accelerando or ritardando can be achieved in two ways: through tempo change, or through change of note durations (e.g. quarter notes to eighth notes). SCAMP allows music to happen on multiple speeding and slowing clocks at the same time, but the metronome markings/accel./rit. can only express one layer of tempo change; the rest must be done through speeding and slowing note values.

Did that help? The clocks in SCAMP are very powerful, but have always been one of the hardest things to explain!

oh yeah, I missed this line, which was decisive. thanks for the clarification.
and also the trumpets slowing down is written down by means of tuplets, so accelerando remains valid.