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2 channels shift for 1/4 tone playback?


In OM-preferences under MIDI / micro-intevals there are options for number of channels: 4 / depending on approximation. Yet, when I choose ‘depending on approximation’ and klick apply, it turns back to 4 again. It seems OM does not accept the second option.
Namely, I have created 1/4 tone that shifts 0mc and 50mc pitch wheel between 2 channels (not 4 as OM default). [Since I am using external instruments for playback (through multiple instances in Logic) this option saves CPU significantly.] Yet, since OM does not allow to apply the option ‘depending on approximation’ (that I have arranged as a personal MIDI setup), it continues to send half-tones to the third channel. Is there a way to overcome this automatisation in OM?

All the best!


Dear Aliser,

For the first issue, yes it seems that there is a bug here. Thanx for reporting. In order to use the usual OM behavior just ignore this option and leave it by default as 4.

Second matter: Yes of course you can explicitly set only two channels in order to use 1/4, However it needs to be either 1-3 or 2-4. That’s the way OM works, ie the channels for 1/4 tone are paired this way:

(see tutorial 10)
That is the reason why OM automatically sends the 1/4th tones to channel 3 when they are played on channel 1. This behavior cannot be tweaked unless changing the midi kernel code.

Here is a recap:

the patch:
midi_recap.omp (34.7 KB)


1 Like

Dear Karim,

Thank you for your answer! (As always, you are the first to help!)

Well I have to make lot of adjustments since I use a lot of instances. (I wasn’t aware of the fact that OM pairs channels for microtonal playback in this manner.)

All the best!