[Fluxus] scala.scm, rev. 1

[Kassen]

On 21/12/2011, Joel Matthys <joel at matthysmusic.com> wrote:

> I think most people who want to do microtonal stuff will want to do it
> with equal temperament, and that's already implemented. Scala files
> aren't really suitable for microtonal because it's possible to define
> vastly different interval sizes from one note to the next, so I think
> anyone who tries it should be happy with what they get. The "purist"
> approach would be your "brutal" method, (floor ) the keynum, but I think
> a little interpolation would be nice.
>

I agree. More strongly even; when we do want to be in a tuning and
want to round floats we will most likely want to do that relative to
some scale, not to the tuning itself.
That way we could -for example- turn a scaled (sin (time)) in to a
sort of melody.

Here is a part of a toolset I'm working on;



(define major (list 0 2 4 5 7 9 11))
(define minor (list 0 2 3 5 7 9 11))
(define acoustic (list 0 2 4 6 7 9 10))
(define whole (list 0 2 4 6 8 10))

;gets the nth note of a given scale
(define (in-scale myscale note)
    (let* ( (note (inexact->exact (round note)))
            (l (length myscale))
            (r (remainder note l)))
        (+
            (* (quotient note l) 12)
            (if (negative? r)
                (- (list-ref myscale (+ l r)) 12)
                (list-ref myscale r)))))

;rounds to the nearest note that is in the given scale
(define (to-scale myscale x)
    (let*  ((myscale (append myscale '(12)))
            (ret 0)
            (over (quotient (inexact->exact (round x)) 12))
            (over (if (negative? x) (- over 1) over))
            (x (- x (* 12 over))))
        (for ((n (in-range 0 (length myscale))))
            (when (<
                    (abs (- (list-ref myscale n) x))
                    (abs (- ret x)))
                (set! ret (list-ref myscale n))))
        (+ ret (* over 12))))


Might be interesting/fun/helpful. I'll publish the whole thing once
I'm at least sure of it all myself and we can see whether others like
it and perhaps push it in.

Yours,
Kas.