Describe your issue:
When I use time-synced delays (tested with analog and tape) and the QC is receiving MIDI Clock (from pirate midi bridge6 controller), the repeats detune/warble quite drastically
Steps to reproduce your issue:
Connect midi controller’s output to QC’s midi in, and send midi clock from it. The QC’s tempo led will blink blue
Create an empty preset and add a tape delay block (M or S)
Enable the sync toggle on the delay block, and play the guitar. The sound of the repeats is very detunes randomly and is not pleasant to listen
Disable the sync toggle on the delay block, and the problem goes away
I am not convinced that the midi implementation is rock solid. For example, I cannot get the looper to midi sync (and I have plenty of experience getting midi clock sync with other loopers).
It is normal for repeats to detune when the tempo changes; this can also create some kind of “warbling” effect. That’s actually expected behavior especially for tape delays: when delay times change, the tape gets sped up or slowed down → detuning happens.
If this occurs when tempo is controlled externally via MIDI, I suspect that the QC detects tempo changes from the MIDI signal and adapts its internal tempo accordingly → detuning effect. If your MIDI controller is sending a steady tempo signal, this shouldn’t happen, so there’s really two possible sources for this problem:
The MIDI clock data from your controller isn’t steady
The QC’s detection isn’t good enough to keep the tempo smooth (some “jitter” in detecting the tempo)
It should be easy to determine which element is at fault: if you try multiple alternative sources of MIDI clock (e.g. PC/MAC with a DAW, a synth that sends MIDI clock, or even another QC) and the problem persists, it is probably the QC’s tempo detection that is too “nervous” and adapts the tempo on every little MIDI “jitter”. Tempo detection should apply some kind of smoothing algorithm so tempo isn’t affected by small jitters and normal MIDI protocol quantization issues, but rather adapts the tempo smoothly over time. Some of my devices take 2-3 seconds to adapt to more drastical tempo changes…
Give it a test with other clock sources - if the problem persists across multiple clock sources, NeuralDSP should be notified - they’ll need to work on the tempo detection algorithm…
That makes sense. At least in my case, I’m using a Morningstar MC8 to send the MIDI clock, and have used it’s MIDI clock out with several other devices and manufacturers and never really had this problem. My Timeline never had any issue with the clock from the MC8, but pretty consistently now the QC has not liked receiving clock data.
I’ll have to set up a switch on my MC8 to stop the midi clock stream to see if the warble stops when the MC8 stops sending clock data.
to your first point, totally understand the expected behavior of tape delays. And really I expect the stretching when changing tempos, but the warbling effect is a very noticeable constant detuning effect that never resolves until you turn off the sync switch on most devices. It even happens for me on the Chorus engine device.