[Question] How much jitter is there?

[schollz]

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 and rtmidi 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

[schollz]

Jitter from Raspberry Pi is bit higher, measured on op-1 on 1/8th notes at 220bpm:

Measurement method:

[schollz]

Interestingly, adding latency doesn't seem to help much more:

Raspberry Pi no latency:

Raspberry Pi w/ 1s latency (scheduled):

[schollz]

Windows comparisons.

WIthout latency:

With latency:

[0atman]

nice research!