Rob Hinkal, the founder of Rob’s Virtual Open Mic, asked if I could create a VCV patch based on prime numbers in commemoration of prime number VOM #113. Well, yes I can…
Sequence 1 – Length 11 with step intervals as semitones of +5, +5, +2, -5, +3, +7, -17, +19, -7, -5, (-7 to return)
Sequence 2 – Length 5 with step intervals as semitones of +5, +3, -3, -5
Each sequence drives two voices in parallel, but with slightly different tempos: 281 BPM and 283 BPM – a difference of 2
Sequence 2 runs 13 times slower than sequence 1
The patch runs for exactly 113 steps of sequence 2 at the 281/13 BPM rate
Disregarding fractional seconds – play time is 513 seconds
or 5 minutes, 13 seconds, 67 rounded centiseconds
The patch uses 23 modules. I was tempted to add some more modules to sculpt the sound a bit more, but I decided to keep the count at a prime number. I did not want to add 6 additional modules to reach the next prime at 29.
The slightly different clock tempos result in phase shifting, a common compositional technique used by Steve Reich. As the two voices drift in and out of phase, interesting rhythmic and melodic changes are perceived that are not present if played as a single voice.
Both voices start in phase, but over time the one voice gets further and further ahead of the other. Had I allowed the patch to play for 5 minutes 30 seconds, then the fast voice of sequence one would have gotten far enough ahead that the sequence 1 voices would have gotten back in phase – both playing the same sequence step at the same time, though not at step 1. I stopped about 16 seconds before that could occur.
I haven’t bothered to calculate how long it would take for sequence 2 to get back in sync, let alone how long it would take for all voices for both sequences to get back to playing step 1 at the same time.
Use the upper left CLKD Reset and Run buttons to initialize and start the patch. It will automatically stop after 5 minutes, 14 seconds. You can press the upper right EVENT TIMER Reset button while playing to disable the auto-stop.
