Not sure what’s going on here. Running Ubuntu on an iMac, with onboard Intel PCH 8/Cirrus CS4206 and an M-Audio Fast Track Ultra 8R on USB. Recording is fine, but for playback I only get stereo when going through the onboard card. If I pan a track when playing back through the FTU I’ll get a slight variation in volume, but no movement across the stereo picture at all.
The FTU is set up with master output as audio_out 1 → system:playback_1 and audio_out 2 → system:playback_2, but I’ve also tried 1 → 1 & 2 → 1, 2 → 1 & 2 → 2, and 1 → 1 & 2 → 1 & 2 → 1 & 2 → 2 (which doubles the overall levels), with no improvement. The PCH does stereo just fine with audio_out 1 → system:playback_1 and audio_out 2 → system:playback_2.
Headphones are fine, cables are fine, next thing I can think of is pulling the FTU apart to confirm that they really are stereo sockets as documented (which won’t help with playback, but I’m at the stage where I’m getting suspicious about everything).
System setup is factory-standard (desktop) Ubuntu with Alsa and Pulseaudio, but no Jack.
Logs are mildly concerning but there’s no other observable misbehaviour at runtime:
2024-11-07T12:21:01 [INFO]: AlsaAudioBackend: adjusted output channel count to match device.
2024-11-07T12:21:01 [INFO]: AlsaAudioBackend: adjusted input channel count to match device.
2024-11-07T12:21:01 [WARNING]: AlsaMidiIO: Cannot acquire realtime permissions.
2024-11-07T12:21:01 [WARNING]: AlsaMidiIO: Cannot acquire realtime permissions.
2024-11-07T12:21:01 [WARNING]: AlsaAudioBackend: cannot acquire realtime permissions.
2024-11-07T12:21:03 [INFO]: Loading menus from /etc/ardour6/ardour.menus
2024-11-07T12:21:03 [WARNING]: Falling back to Reasonable Synth for Midi Audition
2024-11-07T12:21:03 [INFO]: Loading user ui scripts file [~]/.config/ardour6/ui_scripts
2024-11-07T12:21:03 [INFO]: Loading plugin order file [~]/.config/ardour6/plugin_metadata/plugin_order
2024-11-07T12:21:03 [INFO]: Loading history from [~]/ardour/[blah blah]/[blah blah].history
Have I missed a setup option somewhere? Any help appreciated.
What do you mean stereo sockets? The Fastrack Ultra 8R has 8 mono sockets on the rear panel.
That seems to be what you implied here unless I misinterpreted:
I took that to mean that you are using the ALSA backend,and system:playback_1 you expect to be mapped to line out 1 jack on the rear of the interface, and system:playback_2 mapped to the line out 2 jack on the rear of the interface.
Is that correct?
In the audio connections manager, each track connects to a two-channel master bus, with the panner outputs going to master-L and master-R? and Master bus outputs go to system:playback_1 and system:playback_2?
So you are only using headphones, or also using the line outputs?
M-Audio had a Windows or Mac application which could mix signals to the various outputs.
Do you know what controls that routing when you are not using the application? The routing tool lets you control level and panning from each channel to each physical output, so if the default (or previously saved configuration) is channels panned in the center to multiple outputs that could explain the behavior you see.
Ah whoops, some ambiguity there: I’m using the front panel headphone sockets, which are documented as outputs 1 & 2 into headphone 1 and 3 & 4 into headphone 2. Neither is playing back as stereo.
All configurations is through Ardour, and I’m trusting it to handle the back end however it likes. The configurations are descriptions of Ardour’s routing grid. Here’s screenshots of the PCH and FTU setups, to hopefully remove all confusion:
As far as I can tell Ubuntu is leaving the FTU alone outside of Ardour. System hardware is set for built-in for playback, and I don’t see anything specific to the FTU from alsactl via dump-cfg and dump-state. Could definitely use a proper FTU-specific mixer for an overview, but the one that’s on github is failing with broken dependencies so ah well.
You just got me wondering though, and I just now hooked up the line outputs (1 and 2) in turn and used the output tests on the system sound preferences. Both channels (nominally left and right) are each giving me full volume for each speaker’s audio (for all of 7.1) regardless of where it should be, so I’m thinking this could well be either an FTU issue or Pulseaudio mixing channels down to mono for some reason?
Again though: it’s not doing that for the onboard sound. Huh. Will crawl through Alsa/Pulseaudio documentation and see if any hints leap out.
Are you not using the ALSA backend? Pulse backend is not recommended for most use.
My guess is that you need to find a Windows machine that can run the configuration software tool and set the channel panning.
You could check by disconnecting any connections in the ardour connection manager from channel 2, play something in ardour which then only had a connection to channel 1, and see if you hear any audio in the second channel output.
Make sure to use the ALSA backend, that takes over the interface for exclusive use by ardour so there is no question of a system sound server doing anything unexpected.
… so I’m not entirely sure what happened, but it’s working now.
My best guess is that having finally gotten wxPython properly installed (the secret step in case anyone comes by from google: sudo apt-get install build-essential libgtk-3-dev), running the FTU Mixer may have done the channel resets that would otherwise involve the Windows/MacOS tools you mention. I’m very keen to avoid stepping through the code to figure out exactly what happened in there, but I jiggled the Aln1 slider for Out1 and it could be that that was enough to reset panning.
You’re quite right on the ALSA/Pulse – I’d just come from the desktop preferences front-end, which I think is Pulse (probably wrongly) and so had that on the brain at the time.
Many thanks! If that jiggle was what did it then you were likely bang on the money with what needed a reset, and we might just have learned that the Python tool is adequate for the job too.
