Yes the numbers are a bit odd at first glance but what I’m getting at is musically related tape speed control. Think the mannequins W/ (holding play and moving the toggle up to double or down to halve) or magneto when in shift mode. Doubling or halving the speed keeps the pitch related to the original. The speed difference also really fun.
I got the numbers from the strymon magneto manual:
From there I experimented Andy found these values worked.
250 is 1/4 speed = -2
500 is half speed = -1 octave
750 is 3/4 speed = a 5th below
1000 is original playback
1500 is 1.5 x speed = a 5th above
2000 is 2 x speed = 1 octave
3000 is 3x speed = 1 octaves and a 5th
I added the 750 and 1500 as it seems relevant but I could be wrong on my maths (not my strongest area) but it sounds good regardles
Having a control over the speed that snaps to these related pitches is awesome.
Does that clear things a little?