Example 1. The midi-channel-pressure event.

(define (chan-press reps dur amp chn)
  (process repeat reps
           for k = (between 60 80)
           output (new midi :time (now)
                       :keynum k
                       :duration dur
                       :amplitude amp
                       :channel chn)
           ;; ramp pressure up and down for each note
           each p in '(0 60 120 60 0) as i from 0
           output (new midi-channel-pressure 
                       :time (+ (now) (* dur 1/6 i))
                       :pressure p
                       :channel chn)
           wait dur))

(events (list (new midi-program-change :time 0 :channel 0 :program 41)
              (chan-press 10 2 .8 0))
        "test.mid")
⇒ "test.mid"