23 Feb
2023
23 Feb
'23
10:39 p.m.
On Thu, Feb 23, 2023 at 08:43:52PM +0100, Jeanette C. wrote:
In my example: I want to change the tempo from 120BPM
to 150BPM over
four bars of equal length.
What you want here is probably an exponential mapping from bars or
beats to tempo.
For example if you want to change from 1 to 4, a linear mapping
would have (1 + 4) / 2 = 2.5 halfway, and an exponential mapping
would have sqrt (1 * 4) = 2 halfway.
For 120 to 150 it would make very little difference, 135 vs 134.16.
So if the start and end values are A and B, you would make a linear
function from log (A) to log (B), and then use exp () on that to
find the tempo at any point.
Note that this is a exponential mapping from bars or beats to
tempo, not from time to tempo (because as the tempo is changing,
so does the duration of a bars or beat).
Ciao,
--
FA