Troubleshooting MIDI Feedback Loops

A MIDI feedback loop occurs when the transmitted MIDI data is immediately routed back into the instrument. This can cause all sorts of problems. When you play a note from the keyboard or turn a knob, those actions simultaneously affect the internal synth engine, and send out MIDI data. When a MIDI message telling the synth to do something is received concurrently to the same action being performed internally, this creates a conflict. Issues caused by MIDI feedback are vast, but common issues we see are hung or stuck notes, and erratic parameter changes.

The first thing we always recommend is to disconnect all MIDI and USB from the synth if you’re experiencing an issue. If you suspect there may be a problem with the MIDI configuration, or are just unsure of where to start, unplug everything except for power and headphones and test for the issue. Then, introduce any MIDI I/O and notice when the problem arises. If you’re unsure if MIDI is factoring in to what you’re experiencing, this is a great way of isolating the issue.

There are various ways to deal with a MIDI feedback loops. On our synths, you can navigate to the Global menu and then set the global for Local Control to OFF. This will disconnect the keyboard and front panel controls from the internal synth engine, so that the synth engine is controllable by MIDI only. Setting Local Control to OFF is another good way to check for a MIDI feedback loop: if the problem goes away when Local Control is OFF, there’s a loop happening. However, if you choose to set Local Control to OFF, remember to set it back to ON if you want to use the synth standalone.

It is also good to note that MIDI feedback more commonly happens while using USB over MIDI DIN, because by default USB offers two-way MIDI data transfer. One easy solution is to use a USB to MIDI interface. This provides an easy way to physically break MIDI feedback loops, and ensure MIDI is not being unnecessarily sent or received. For instance, if you are sequencing the synth from a DAW, you only need a single MIDI output connected to the MIDI input on the synth. No MIDI data will loop back through the synth, and thus you can leave Local Control on and use the synth’s panel controls while sequencing the synth.

Alternatively, you can configure your DAW to not route received MIDI commands immediately back out to the device the commands are received from. Refer to the documentation for your DAW for how to achieve this. Good strategies include muting the MIDI track in your DAW which is connected to the synth while the track is being recorded to, and turning off MIDI Soft Thru. Additionally, for tracking down the loop, MIDI Monitor for Mac and MIDI OX for PC are both free applications that allow you to monitor the MIDI data being transmitted from a device. Set up your instrument and DAW to recreate the issue, then monitor the MIDI data by selecting your synth in the monitor software. If you’re in need of more advanced MIDI routing, MIDI Pipe for Mac as well as MIDI OX for PC allow you to filter MIDI messages.

If you’re still experiencing issues with a MIDI feedback loop, or have questions when it comes to configuring your MIDI setup with our synthesizers, please contact Support. We’re here to help!