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[Question] How much jitter is there?
Testing using 1/8th notes at 110 bpm on 3 instruments (nts-1, op-1, sh-01a). Two samples taken while running, for 20 seconds each. The samples were processed, aligned and differed.
Takeaways:
- little difference between
portmidi
andrtmidi
libraries - instrument makes a difference, nts-1 jitters between 0-20 ms, while op-1 jitters between 0-2 ms
- little difference between one instrument and three simultaneous instruments
Some representative examples:
Measured from the nts-1, one instrument:
Measured from the nts-1, three instruments:
Measured from the op-1:
Measured from the op-1, 1/8th notes at 220 bpm:
Measured from the op-1, using rtmidi instead of portmidi:
Measured using a song I wrote at 110 bpm:
pattern a
tempo 110
instruments nts-1
legato 1
C1 Eb G C Eb G C Eb
instruments op-1
legato 50
Bb3D4 G3 Eb- Eb . . . . Bb3Eb4 G3 Eb- Eb . . . .
Bb3Eb4 G3 Eb- Eb . . . . Bb3Eb4 G3 Eb- Eb . . . .
G3C4 Eb3 C- C . . . . G3C4 Eb3 C- C . . . .
G3C4 Eb3 C- C . . . . G3C4 Eb3 C- C . . . .
instruments sh-01a
legato 90
Eb3GBb
D3FBb
C3EbG-
C3EbG
Jitter from Raspberry Pi is bit higher, measured on op-1 on 1/8th notes at 220bpm:
Measurement method:
Interestingly, adding latency doesn't seem to help much more:
Raspberry Pi no latency:
Raspberry Pi w/ 1s latency (scheduled):
Windows comparisons.
WIthout latency:
With latency:
nice research!