Currently, the PolyBrute is has very unstable playing anytime local control is set to OFF that makes it borderline unplayable. Depending on what the octave switch is set to, notes tend to hang until they are played again.
This issue does not happen at all with the octave switch is set to 0. For some, the local control feature might seem useless, but it is crucial for anyone running a DAW-centric setup or any other complex midi setup (e.g., using sequencers or MIDI interfaces). In my case, I turn off local control on all of my synthesizers. For each synthesizer, it follows the same setup: A note is played on the synthesizer → The MIDI for this note is sent to Ableton via USB → Ableton records the note and processes any filtering or MIDI effects → This resultant MIDI note is sent back to the synthesizer via USB. It is worth mentioning this because it will be important for later on.
It's a shame because I have genuinely considered selling the PolyBrute because of this issue; however, its sound is so good that I was intrigued enough to try and find why this is happening. So, I did some "black box" testing and found out some interesting patterns about this bug that I have not seen mentioned on the forums. I hope this information can help with solving this issue.
First, here are the conditions to cause this bug:
- Turn off local control (Settings → MIDI → Local Control)
- Reroute PolyBrute's MIDI output back into the PolyBrute MIDI input via a DAW using the PolyBrute MIDI channels
- Load any patch and set the octave switch to -1
- Play and hold any note. While doing this, tap the note that is one octave above the note you are holding down
- The original note you were holding (i.e., the lower note) will hang until played again.
However, the behavior is reversed when the octave switch is set to a positive value. Say, for example, we have the octave switch set to 1. Then, we repeat the same steps above. The higher of the two notes played, rather than the lower, will be the note that hangs. Another interesting thing is that when the octave switch is set to a nonzero value, that value determines the "distance" that the two notes have to be played in order to trigger the bug. For example, when the octave switch is set to ±2, you have to repeat the steps above but tap the note that is
two octaves above the note that you are holding down.
Here is where things got really interesting. I decided to see if anything changed if I did the following setup: A note is played on the PolyBrute → The MIDI for this note is sent to Ableton via USB → Ableton records the note and a MIDI effect is applied that shifts the pitch +24 semitones → This resultant MIDI note is sent back to the synthesizer via USB. If you do this with the octave switch set to -2,
every single note you play will hang. If you do this with the octave switch set to -1, the bug occurs when a note and its octave is played, with the higher note hanging. If you repeat this with the MIDI effect set to shift the pitch -24 semitones, the behavior is mirrored. So, every note you play will hang with the octave switch is set to +2. Similarly, when the octave bug happens but the lower note will hang.
I decided to see if these issues would continue if we used another keyboard to control the PolyBrute. So, I tried this setup: OB-6 → Ableton → PolyBrute. There were no issues whatsoever when controlling the PolyBrute with the OB-6's MIDI. When I compared the MIDI messages between the OB-6 and the PolyBrute, they looked identical other than the velocity of course.
To dig even deeper, I repeated the original steps written out above (where the octave switch is set to -1); however, I had the MIDI from the PolyBrute and the OB-6 being sent to the PolyBrute. When I played the lower note on the PolyBrute and tapped the higher note on the OB-6, the bug occured.
When I reversed this, and played the lower note on the OB-6 and tapped the higher note on the Polybrute, the bug does not occur. This and everything else has led me to these thoughts:
- The support team has suggested splitting the MIDI input and output as two separate groups in Ableton, where each group uses a different MIDI channel. This suggestion will not solve anything; it makes no difference whatsoever. In fact, no form of convoluted MIDI routing will work as long as the PolyBrute is the source of the MIDI that is being routed back to the PolyBrute. I even tried duplicating the PolyBrute's MIDI messages into another fake MIDI device and routed that back into the PolyBrute. It did not make any difference. This leads me to my next point...
- I am confident that the local control has not been implemented correctly on the firmware. I think that the keyboard is still sending some type of data to the synth itself while sending data to MIDI out that is causing the stuck notes. (In addition to this, the original firmware I had when I originally got the synth had a bug where hitting the sustain pedal while local control was set to off would cause the sequencer to trigger on and off insanely fast causing extreme chaos. Given this, that makes me believe this theory about the incorrectly implemented local control more.)
Please let me know if any clarification on this is needed; I want to help the most I can with this issue.
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