Audible MIDI noises and other buzzing stuff [SOLVED]

#1

I have a setup involving 2 axo's mounted together on a steel 19" rack panel with a pots and LED's connected to GPIO, a volca, keystep and launchcontrol, connected as seen here:

axomidinoise.jpg907x702 161 KB

There are some massive noise issues.

If the axo's are running from the USB ports of a PC or latop it's insane, but from seperate USB wall warts it's bareable. Any ideas are welcome but the electrical noise is not such a big issue for me, I can live with some grunge.

What really bothers me is that I can hear audible noises for every MIDI message coming through - whenever I touch any of the controls on the MIDI controllers (CC changes and note inputs) and the constant hum of the MIDI clock. I just can't figure out how the sound of MIDI data is bleeding into the audio output. Is it a ground/shielding thing?

Is it something in the patcher? Both are using a773's "midithru_incl_clock" object, that's the only MIDI out either of them use. They both use several MIDI in objects: clock, note and CC. Here's the patches if anyone wants to take a look, but I can't imagine it's because of that:
ORDE_breaks.axp (97.8 KB)
CHAOS_thrufx.axp (33.0 KB)

#2

Hi, have you tried powering the axoloti from the socket on the side of the axoloti instead of the usb socket?

Doing this cured a ton of noise for me.

I think the midi noises might be power related: When my axo is powered via usb and is noisey the noise changes depending on what the leds on an attached controller are doing (if they are flashing/changing colour, etc).

Maybe your problem is different though...

#3

Sadly, with the way they are mounted in the case it's only possible to do that for one of them - but I'll give it a try!

EDIT: nope, no difference, even with both running via PSU (I removed a side panel)

#4

After some more testing, it seems the Volca seems to be at fault, if I disconnect either the MIDI in or audio out of the volca (even if powered off or completely disconnected from power) the MIDI noises go away.
I'm guessing the MIDI out of right Axo feeding into the Volca, the Volca audio going into the left Axo, and the MIDI and audio from the left Axo going to the right one is causing some sort of loop...

EDIT: replaced Volca's audio cable, problem solved!