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MIDI Control+Unison Issue?

MIDI Control+Unison Issue?
« on: January 03, 2021, 04:39:41 PM »
Not sure if this is a bug necessarily, but my Prophet 5 acts funny in Unison mode when MIDI control is on. I was wondering if anyone else was having a similar experience, or knows if this sort of thing is normal.

When MIDI Control is on, my Prophet’s keyboard does not respond properly in Unison mode. It’s as though the gates are cutting out when you release a key, regardless of key mode or programmed release values.

This does not seem to occur when playing in Poly Mode. I only observe this behavior in Unison, and only while MIDI control is on.

Perhaps this is normal when a synth is open for MIDI communication, but I don’t recall other DSI/Sequential synths I’ve owned ever reacting this way.

To check, I just tested my OB6 (module) and it does not exhibit this behavior in unison mode. It plays as you would expect when MIDI in on.

Is anyone else experiencing (or can replicate) this on their Prophet 5?

Re: MIDI Control+Unison Issue?
« Reply #1 on: January 03, 2021, 05:51:15 PM »

Activating “Local Off” or “Local S0n” seems to correct this Unison behavior, though I couldn’t explain why.


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Re: MIDI Control+Unison Issue?
« Reply #2 on: January 04, 2021, 12:23:11 AM »
In most cases where "Local off" solves the issue, there is a midi loop anywhere in your setup. The loop results in multiplying note on/off messages. That means the sound engine receives more than one note off message in your case. The first message will stop the sound as you would expect it, meaning it will trigger the release phase. The second (and perhaps more) note off messages stop the sound immediately, by cutting the envelopes, because you are in unison mode. You don't recognise this in Poly mode, because the duplicate note on/off commands trigger a different voice and leave the envelopes of the first voice alone. But if you listen closely, you should hear two voices sounding in poly mode, too.

If you are using a DAW and want to work with "Local on" you should make sure, that your DAW does not send incoming midi data back to your synth. That would exactly result in the described behaviour of doubling notes.
Prophet Rev2, Novation Peak, Arturia DrumBrute Impact, Korg Kronos 2 88, Kurzweil PC 361, Yamaha S90ES

Re: MIDI Control+Unison Issue?
« Reply #3 on: January 06, 2021, 06:38:54 PM »
Thanks Jok3k!

I think you’re right about the DAW. Pulling out of Logic and just going through the mixer definitely stopped that behavior, just as disabling the local control did inside the DAW. So Logic must have been sending notes back simultaneously.

If I get your breakdown, with the local control disabled, I wasn’t really hearing my key press anymore, but rather Logic just firing the note back into the Prophet, so no more double trigger. Interesting. I appreciate you helping me understand why that fixed the behavior.

I didn’t think I had anything set any differently than usual, but I must have, cause it was definitely doing something weird that none of my others synths have ever done. I’ll try to replicate the issue and then keep an eye out for that in the future.

Thanks again!