• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Interference between audio over USB and MIDI over USB. Why?

DirtDog

DirtDog

Jun 7, 2002
8,360
28,334
The Deep North
#1
Been experimenting a bit and have a use case where I’m experiencing interference with audio and midi over USB in Logic Pro X.

The interference problem arises when I instantiate a software instrument track and send MIDI signal from an external controller in. Logic project where I have set up an audio track ( guitar signal from Focusrite 18i20 interface into a VST amp sim).

Before the software track is instantiated, the guitar signal is flawless. Once I instantiate the software instrument track, the guitar signal is severely degraded…digital pops and chirps at best. Doesn’t affect previously recorded audio tracks, but messes up any new audio track.

I had both USB inputs coming through a USB hub. Then I tried taking the hub out of the mix

I’ve also tried different interfaces and this still persists. Basically, I can record/monitor any number of audio tracks but as soon as I add in a software track things go sideways.

I seem to think these problems started when I hooked up an Expressive E Touché device but the problem appears with any midi controllers I use.
 
#4
Just ran some experiments. CPU load is fine. Even with multiple tracks and plugins, it's not even hitting 50% CPU load with Logic and everything else running in the background. I'm on a Mac Studio with an M1 chip and 32 GB RAM.

I'll keep the cable shielding in mind, but I don't think that's it. With the experiments I've run so far, I don't have this interference happening with most of my VST software instruments (stock Logic and some 3rd party). Except one.

That one is Arturia Analog V. Everything runs fine and as soon as load up a new track with that plug-in, guitar/bass audio craps out 100% of the time. But it worked fine up until recently.

Got a few other tests to run (my other Arturia VST instruments), but I think I may need to reinstall/update that VST. The crappy part is that I need to restart the Mac reboot the interface each time the audio goes haywire.
 
Last edited:
#5
DirtDog said:
I need to restart the Mac reboot the interface each time the audio goes haywire.
Click to expand...
Damn, that sucks :/
I had a similar issue with noise. I wanted to move my Keylab 88 to a different wall, and used a longer USB cable that I had lying around. The only thing that I could narrow it down to was the generic cable I used without the ferrite choke.
 
  • Like
Reactions: DirtDog
#6
Just a WAG, but does the external MIDI device run MPE?
If you have a MIDI monitor app or vst you can watch what all comes in over MIDI. MPE devices sends tons more data essentially all the time.
I don't have problems with MPE but I could see how some apps might have problems processing all the data.
 
  • Like
Reactions: DirtDog
#8
EvilJ said:
Damn, that sucks :/
I had a similar issue with noise. I wanted to move my Keylab 88 to a different wall, and used a longer USB cable that I had lying around. The only thing that I could narrow it down to was the generic cable I used without the ferrite choke.
Click to expand...

I’ve pretty much eliminated USB cables as the culprit. Seems to me the problem is between Logic and the Arturia plugin.
 
  • Like
Reactions: EvilJ
#9
I stumbled onto the solution a few months ago. Thought I’d share here to save someone else the headache. And to remind myself when it happens again.

On MacOS, the “enable microphone” icon on the top menu bar needs to activated. It’s yellow/orange when activated.

If it’s deactivated, some small amount of signal passes from the interface to Logic but not all of it. Sounds like interference. Same for MIDI over USB.
 
  • Like
Reactions: smeet, EvilJ and claudel

Latest posts

Top Bottom
Back