While experimenting with the Yamaha QY70 and QY100, I stumbled into something unexpected… You can create MIDI feedback loops resulting in compelling glitchy embellishments overdubbed onto existing user tracks. All you need is a single MIDI cable.

This isn’t an intended feature, it’s a side effect of how MIDI routing works. While most modern MIDI sequencers have protections in place to prevent MIDI feedback, the QY sequencers do not, and this can be taken advantage of to generate glitchy repetitions. By physically looping the MIDI output back into the MIDI input, the QY begins to re-record its own data with a delay, creating layered, evolving, and often chaotic results.

What it Sounds Like:

You can hear this technique in action on a lead instrument in the following starter template:

Deform
  • The lead enters around 0:25
  • That part was generated using MIDI feedback, then cleaned up afterward using quantization

I also utilized this technique more loosely on another starter template resulting in a beat that feels like its fragmenting as it plays out:

Glitch
  • MIDI feedback has been applied to the percussion as well as piano and other instruments to create an unstable rhythm
  • No quantization was used in this example, however Undo/Redo was used heavily and multiple re-recordings were done to get the effect sitting right in the pattern

The Technique – Creating a MIDI Feedback Loop

The setup is simple:

  1. Create a sequence on any track
  2. Connect one end of a standard MIDI cable to the MIDI OUT (leaving the other end of the cable unplugged for now)
  3. Start an overdub recording on the sequenced track you want to glitch
  4. Briefly touch the unconnected tip of the MIDI cable to the MIDI IN (This results in MIDI feedback, allowing MIDI data to be recorded and layered onto the existing track’s sequence)
    • (Optional) Use Shift+F4 to Undo/Redo the results to decide whether to keep them or reattempt the recording.
    • (Optional) Quantize the results to bring the glitch effect in time with the overall groove.
    • (Optional) Use the Thin Out job to reduce the MIDI CC data density (where applicable) to keep the files small and make space available in the pattern for more data.

What causes this effect?

  • Notes exit the QY via MIDI OUT
  • They travel through the cable
  • They re-enter through MIDI IN (when the cable touches the MIDI IN port)
  • They get recorded again… slightly delayed and their playback piles up as more data loops through MIDI cable while momentarily plugged in

That delay—while small—creates a feedback loop, causing notes to stack, echo, and mutate over time.

Important Behavior and Limits

This technique pushes the device in ways it wasn’t really designed for, so there are a few things to be aware of:

  • Exponential MIDI buildup
    Each pass adds more data → things escalate quickly
  • Cable length and recording BPM are what determines the delay
    → The longer the MIDI cable, the longer the data spends traversing the cable resulting in a longer delay.
    → Alternatively, the recording BPM can be adjusted to change the delay as incoming notes will align differently based on the rate of the overdub recording’s playback.
  • Temporary freezes can happen due to MIDI buffer hitting it’s limit
    This is harmless,
    → Just unplug the MIDI loop to stop the feedback.
    → In situations where too much MIDI data has been recorded, the playback may freeze entirely, requiring you to power the device off and on, so use this effect lightly. This is also why it’s useful to apply the Thin Out job to tracks where possible to remove overabundant MIDI CC messages.
  • Momentary overload is the “effect”
    The glitchiness comes from the system struggling to keep up

With all this said, you should treat the cable like a momentary effect trigger, not a permanent connection.

Creative Uses

This goes beyond just glitch effects. A few directions worth trying:

  • Evolving lead lines
    Notes compound into new phrases you wouldn’t normally write, adding embellishments to existing sequences
  • Dense rhythmic layering
    Especially useful on hi-hats or percussion
  • Pseudo-delay / echo textures
    More unstable and organic than standard delay
    → Sudden cutout of MIDI Note Off messages can cause hung notes which can be used intentionally within a pattern
  • External device chains / MIDI manipulation
    Route through an external device chain to alter the MIDI data before returning
    → Anything that alters MIDI (filters, processors, a DAW’s MIDI FX, even another sequencer) can reshape the feedback before it comes back in to the QY
  • Multi-track MIDI Out to MIDI In
    MIDI data doesn’t have to be recorded off just one track, multiple could be used as the source, and the glitch could be recorded onto a blank track gathering conflicting incoming data and forcing a new instrument track to play it back.

Final Thoughts

This technique sits somewhere between composition and system abuse. It’s unpredictable, occasionally messy, but capable of producing results that are hard to get any other way on the QY series, and impossible to reproduce on a lot of newer sequencing gear.

If you’re making electronic music on these devices, this is well worth experimenting with. There are so many directions this technique could be pushed, I haven’t even begun to scratch the surface. All it takes is a MIDI cable and some patients recording. Definitely give it a try and let me know what you discover!