Oscilloscope app outputs to only ch 3 on 4-channel audio devices?

#1

Hi, I have the Oscilloscope app v1.1.0 on macOS Ventura 13.7, output set to a MOTU M4. It seems to only output to channel 3 for some reason.

It works if I manually route the channels using a virtual audio interface like Loopback.app.

I’m using the built-in macOS USB audio class drivers, if that matters.

Is this a bug? Has anyone else seen something like this before? Thanks.

#2

This also happens when I create a 4-channel virtual device in Loopback.app on macOS, so it’s probably a general problem with audio interfaces that have 4 output channels.

#3

can you check in two places:

  1. audio midi setup. can you find your motu there, and check the multi speaker setup? make sure you have outputs one and two as primary.
  2. the motu setup. there could also be an option to select default outputs.

i use the ultralite mk3 and it lets me pick default stereo outputs in cue mix fx. if i set it to “main”, then i get the output on channel 1-2, if i select “analog 1-2” (default), then it outputs to channels 3-4.

#4

Thanks for the reply and suggestions!

Speaker setup on the M4 in Audio MIDI Setup is stereo, channel 1 L, channel 2 R. Setting the M4 as the system default output causes other apps (and system alert sounds, if selected) to play correctly to channels 1 and 2.

This also happens with a 4-channel virtual device configured in Loopback.app, so it really seems like a problem specific to Oscilloscope.app. Output is to channel 3 only, and it looks like the sum of channels 1 and 2.

(edit) The beta Function.app appears to correctly output to channels 1 and 2 on the M4, when the M4 is set as the system default output.