Lets say you have a beat at 120BPM, and press one of the keys below…

C1 - Plays at 1/8 speed

C2 - Plays at 1/4 speed

C3 - Plays at 1/2 speed

C4 - Plays at normal speed

C5 - Plays at 2x speed

C6 - Plays at 4x speed

C7 - Plays at 8x speed…

But what about the numbers inbetween? Each octave has 12 notes in it which is divisible by 3 and 4 as well as 6 and 2. Therefore you can keep the beat in time but in interesting ways…

C4 - Normal speed

F#3 - 3/4 speed

D#3 - 2/3 speed

F#2 - 1/3 speed

F#1 - 1/6 speed

F#0 - 1/9 speed

There are loads more, feel free to add some more !

A generalistic formula would serve much better than such tables. I don’t want every tune 120bpm. I’m enough of a nerd to try to derive one when I’m bored. Like calc it with parameters like note number, song speed, 1:1 note and length factor, target ratio. If note number results with fractional = bummer. Equal temperament is just a formula to define ratio between notes, other temperaments could be much harder to hit straight.

Another useful formula could be to calculate the beatings between notes/detune cents. Like let that reese wobble in time perfectly. Been thinking about this quite some time now.

I.e. unless you use some special scala tuning files, renoise should use equal. Other temperaments might have some chords/keys “cleaner” in tune, but others fucked up badly. Equal is a modern compromise to have some beatings everywhere chordwise, but sound ok in any key.