Support and discussion for all of Akai’s modern standalone MPCs including the MPC X / X SE, MPC Live 1, 2 & 3, MPC One / One+, MPC Key 37/61.
By Snizius Sat Apr 26, 2025 9:10 pm
I’m having trouble with the mpckey37 recording the sustain info. When you press the pedal it works as it should but doesn’t record. If I switch the polarity to the left if sustain the notes without pressing the pedal and records it. You have to press the pedal for it not to sustain notes. Has anyone had this issue that can point me in the right direction.

Thanks JB
By Skeeter_Woo Wed May 07, 2025 3:50 pm
Make sure your MIDI Input for Keyboard is both Global and Track

Also, in Sequencer make sure Record Track Mute / Solo Events is turned on and Truncate Duration as As Played.

Have you tried Reset Preferences?
By Snizius Wed May 07, 2025 3:55 pm
I spent a lot of time with Akai tech trying to figure this out. With sustain pedals you have to let off of the pedal right before the loop ends. Or you can play through and then come back and shorten the loop length. The only problem now is if you try to overdub the track anything you play is automatically sustained without pressing the pedal. They said they will have to submit for an upcoming firmware update. No timeline as of now for when this will be fixed.
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By Ultros Wed May 07, 2025 6:16 pm
You need to reverse the polarity of the pedal, either via a polarity swich on the keyboard or on the pedal itself.

If your pedal or keyboard cant flip polarity you can make a cable for the pedal by flipping one of the TS ends. Cut it off, flip polarity in the wires and solder the end back on and mark that cable as sustain pedal. If its built in to the pedal you can cut the end off and solder another one on or do some circuit bending on its pcb.

Sustian pedals are not midi, they are basic signal on signal off and currently your circuit is open by default.

For fun: Plug a ts cable into your keyboards sustain jack, then take a nickle or penny and bridge the contacts on the other end of the jack with the penny. Behold sustain!
Last edited by Ultros on Wed May 07, 2025 6:24 pm, edited 1 time in total.
By Snizius Wed May 07, 2025 6:18 pm
Polarity is set correctly on the pedal. They confirmed this is a bug in the OS that needs to be fixed.
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By Ultros Wed May 07, 2025 6:25 pm
Snizius wrote:Polarity is set correctly on the pedal. They confirmed this is a bug in the OS that needs to be fixed.


That's weird! lolol i guess when its converted to midi they forgot to flip the signal.