Common Music 3: Remix drum loops with Scheme

2022 note: CM may nearly be a dead project, so I'm publishing this more for myself.

Working though porting some old instruments which generated Csound scores from Common Music 1 to Common Music 3. This example illustrates a few techniques I used in my piece Anxious from 1999:

I kept myself to a few drum sounds, primary this loop, which comes from a Jimmy Smith tune originally:

but was known to me through Professor Booty.

Here's the sound this code makes:

Here's jam.aif and the the CM code that references it:

; 14 segments for jam.aif
(define idxdur '((0.018 q) (.697 q) (1.376 s) (1.538 e)(1.869 s)(2.032 s)(2.2 e)
        (2.543 s)(2.705 q)(3.373 e.)(3.895 e)(4.232 q)(4.894 e)(5.236 s)))
; given the dur of a quarter, return tempo
(define (quarterDur->tempo quarterdur)
    (* 60 (/ 1.0 quarterdur))
)
;
; remix - based on idxdur, remix sections of jam.aif loop
;
; args:
; - tem: tempo (should be a float)
; - pan: angle to pan signal (between 0 and 90)
; - amp: attenuate signal (between 0.0 and 1.0)
; - totaldur: process continues until totaldur is exceeded
;
(define (remix tem pan amp totaldur)
    (let* (
        (iter (make-cycle (list
        (make-cycle '(5 6 7 8))
        (make-cycle '(5 6 7 8))
        (make-heap '(0 1 2 3 4 5 6 7 8 9 10 11 12 13 ))
        (make-heap '(5 6 7 8))
    )))      

    (origtem (quarterDur->tempo (- .697 .018)))
)

(process with curtime = 0
    for t = (elapsed #t) ; get true score time
    for i = (next iter)
    for dist = 5
    for pct = .025
    for idx = (nth idxdur i)
    for indx = (nth idx 0)
    for origdur = (rhythm (nth idx 1) origtem)
    for endx = (+ indx origdur)
    for r = (rhythm (nth idx 1) tem)
    for d = (rhythm r tem)
    for p = (/  tem origtem)
    ; faster tempo, the quieter
    for a = (+ .5 (- amp (/ tem 210.0)))
        until (> curtime totaldur)
        do
        (cs:i 3 t d a p pan dist pct indx)
        (set! curtime t)
        (wait r)
    )
    )
)
;
; make-reverb-note
;   Turn instrument on for duration of score
;
(define (make-reverb-note dur)
    (process repeat 1 do
    (cs:i 99 0.0 dur 5))
)
; A verbose way to sprout this process at multiple tempos.
; The result is a Nancarrow-esque tempo canon
(sprout (list
    (remix 100.0 10 1.0 30)
    (remix 110.0 30 1.0 30)
    (remix 120.0 60 1.0 30)
    (remix 130.0 80 1.0 30)
    (remix 140.0 10 1.0 30)
    (remix 150.0 30 1.0 30)
    (remix 160.0 60 1.0 30)
    (remix 170.0 80 1.0 30)
    (remix 180.0 10 1.0 30)
    (remix 190.0 30 1.0 30)
    (remix 200.0 60 1.0 30)
    ) "remix.sco" :play #t :orchestra "sndwarp.orc" :header "f1 0 262144 1 \"jam.aif\" 0  0 0\nf2 0 16384 9 .5 1 0 \n")
; A cleaner, less verbose way to generate the same
(define mixes '())
    (loop for i from 100.0 to 200.0 by 10.0
    do
    (set! mixes (append mixes (list (remix i 45 1.0 60))))
)
(sprout mixes "remix.sco" :play #t :orchestra "sndwarp.orc" :header "f1 0 262144 1 \"jam.aif\" 0  0 0\nf2 0 16384 9 .5 1 0
\n")
; a single instance of remix, with reverb note
(sprout (list (remix 100.0 10 1.0 30) (make-reverb-note 40)) "remix.sco" :play #t :orchestra "sndwarp.orc" :header "f1 0 262144 1 \"jam.aif\" 0  0 0\nf2 0 16384 9 .5 1 0
\n")