arseniiv
commented
5 months ago So what Scala seems to do when mapping size is not 0 (because that’s a case which (a) works perfectly and doesn’t use neither mapping pattern nor formal octave and (b) doesn’t mathematically fit with all the other cases):
Let S be the scale size from SCL, M be mapping size from KBM and P be formal octave from KBM.
First for KBM taken alone, it takes KBM’s pattern placed to start on the scale start note, thus mapping M = 4 notes:
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
x x x x x x x x 0 2 4 5 x x x x x x x xThen it repeats the pattern up and down, each time adding or subtracting P = 7:
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
-14-12-10 -9 -7 -5 -3 -2 0 2 4 5 7 9 11 12 14 16 18 19
\_________/ \_________/ \_________/ \_________/ \_________/
-14 -7 0 +7 +14And only now it finally consults SCL data about which degree is what interval (incidentally using S for that, which didn’t get used before), and also being able to calculate exact frequencies because now it can know the interval for the reference note, so it can calculate the frequency for degree 0 of the scale (which of course may even not appear here in the mapping).
P. S. This should also be applicable to cases when P is larger than S or is negative or zero, really, so probably KBM with P > S might now get accepted!
baconpaul
Using 12edo and a KBM file of the form
makes Scala render these frequencies and quick info about the mapping:
but Surge XT 1.3.0.20a8e16 seems to deviate from those.
Very nice that there’s HTML export, I attached it here: surge_info.zip. Indeed I see degrees of notes in the mapping go
... 7 2 4 5 7 2 4 5 0 2 4 5 7 2 4 5 7 ...which is quite peculiar. In Scala output, degrees (mod 12) are... .3. 5 7 8 .10. 0 2 3 .5. 7 9 10 .0. 2 4 5 .7. 9 11 0 .2. 4 6 7 .9. ...where periods of the mapping are marked with dots.I have a theory about what exactly does Scala do, which so far is consistent with what I tested. I’ll add it in another post later.