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Having pops without jack indicates that either some other software layer is choking (e.g. pulse if the audio is still routed through it) or a hardware issue. Yo

Having pops without jack indicates that either some other software layer is choking (e.g. pulse if the audio is still routed through it) or a hardware issue. You indicate that the hardware is without issue elsewhere, so that leaves the linux ALSA driver/driver settings, pulse (if it's interfering), jack, or the recording app. I do recall some mentions of a few of the Scarlett devices having quirks in the past, though I haven't personally been all that involved in those discussions. If jack or the recording application (connected to jack) were causing the issue then you should see an xrun reported from jack which makes me think that there's the possibility that it's being unexpectedly routed around via pulse (which can cause all sorts of shenanigans) or it's a know ALSA level driver quirk with respect to the device. The latter is unlikely as you're indicating that this is a USB device (IIRC the firewire ones were the more fussy ones). Even if you're not striving for low latency I would recommend some of the audio communities as they're likely to have stressed the same device a fair bit and may have encountered similar issues.

nickjj 8y ago
Thanks. Is there any chance the Windows driver has some special sauce to deal with hardware defects that alsa / pulseaudio aren't aware of? Maybe some crazy edge case defects (since it's not affecting everyone with a Scarlett). I think I am still using pulse mainly because I installed qjackctl and pulseaudio-module-jack, but my audio devices according to pavucontrol were Jack, but it's still being routed through pulse right? I Googled to the end of the world on this device with Linux but came up empty handed. It was just a few success stories.
- fundamental 8y ago
  Typically that approach setups up jack as the primary device user and pulse as the secondary. Your setup involves a usb audio device in addition to what I assume is some builtin audio device on your desktop/laptop. JACK's server only takes full control over a single device, so it's possible that JACK took over something other than your Scarlett leaving a different routing mechanism to shuttle data from the Scarlett to it. As that's a mouthfull, what may be happening is: Dev A <-> JACK <-> Pulse <-> Dev B If that's happening then you'd want to switch the setup to: Dev B <-> JACK <-> Pulse <-> Dev A or Dev A <-> JACK <--+--> Zita-ajbridge <-> Dev B | +--> Pulse Per the windows driver, I have no idea and likely neither do ALSA devs since the source is not available there. If the Scarlett driver is a standard usb-audio device, then it likely should be exceptionally robust and very similar across operating systems.
  - nickjj 8y ago
    You are correct in that I also have a built-in sound card that's on the motherboard, but currently there's no microphone connected to it. I also had my headphones connected directly to the Scarlett. When Jack was wired up with that pulse module plugin, if I talked into my the mic, pavucontrol showed the input bar jumping around. Does that mean it was operating on the correct mic? When I used OBS' jack client, it also picked up the Scarlett's mic once I wired it through qjackctl. I know on Windows I was getting pops and cracks until I installed the Scarlett driver and specifically set the buffer to 512. Any other value would produce pops on Windows (even worse with 1024 which is weird).
    - fundamental 8y ago
      If you look at qjackctl's connection window then the system:playback and system:capture ports should correspond to what jack is directly connected to. If jack is connected directly to your device, then any pops due to xruns should be recorded and displayed in qjackctl.
      - nickjj 8y ago
        Yeah it was set up so that the PulseAudio JACK Sink was set to the system:playback_1 and 2, and then the PulseAudio JACK Source was set to system:capture_1 and 2. There were pops but no xruns recorded with Jack. Then in the OBS case, when I used the specific JACK client (as a secondary test), I wired the system:capture to whatever client came up with OBS. In hindsight, maybe that was a mistake, and I should have instead wired up the JACK sink's front-left/right instead of system capture?
        fundamental 8y ago
        It looks like HN's reply limiter has kicked in preventing further replies, so I'd recommend shifting discussion to one of the resources I've already mentioned. Based upon your most recent comment it is still not clear if jack is connected to the desired device or not. I'd recommend connecting a simple waveform viewer e.g. http://baudline.com/ http://baudline.com/ to system:capture to see what's going on with respect to what jack sees as its input.

nickjj 8y ago

Thanks. Is there any chance the Windows driver has some special sauce to deal with hardware defects that alsa / pulseaudio aren't aware of? Maybe some crazy edge case defects (since it's not affecting everyone with a Scarlett). I think I am still using pulse mainly because I installed qjackctl and pulseaudio-module-jack, but my audio devices according to pavucontrol were Jack, but it's still being routed through pulse right? I Googled to the end of the world on this device with Linux but came up empty handed. It was just a few success stories.

fundamental 8y ago
Typically that approach setups up jack as the primary device user and pulse as the secondary. Your setup involves a usb audio device in addition to what I assume is some builtin audio device on your desktop/laptop. JACK's server only takes full control over a single device, so it's possible that JACK took over something other than your Scarlett leaving a different routing mechanism to shuttle data from the Scarlett to it. As that's a mouthfull, what may be happening is: Dev A <-> JACK <-> Pulse <-> Dev B If that's happening then you'd want to switch the setup to: Dev B <-> JACK <-> Pulse <-> Dev A or Dev A <-> JACK <--+--> Zita-ajbridge <-> Dev B | +--> Pulse Per the windows driver, I have no idea and likely neither do ALSA devs since the source is not available there. If the Scarlett driver is a standard usb-audio device, then it likely should be exceptionally robust and very similar across operating systems.
- nickjj 8y ago
  You are correct in that I also have a built-in sound card that's on the motherboard, but currently there's no microphone connected to it. I also had my headphones connected directly to the Scarlett. When Jack was wired up with that pulse module plugin, if I talked into my the mic, pavucontrol showed the input bar jumping around. Does that mean it was operating on the correct mic? When I used OBS' jack client, it also picked up the Scarlett's mic once I wired it through qjackctl. I know on Windows I was getting pops and cracks until I installed the Scarlett driver and specifically set the buffer to 512. Any other value would produce pops on Windows (even worse with 1024 which is weird).
  - fundamental 8y ago
    If you look at qjackctl's connection window then the system:playback and system:capture ports should correspond to what jack is directly connected to. If jack is connected directly to your device, then any pops due to xruns should be recorded and displayed in qjackctl.
    - nickjj 8y ago
      Yeah it was set up so that the PulseAudio JACK Sink was set to the system:playback_1 and 2, and then the PulseAudio JACK Source was set to system:capture_1 and 2. There were pops but no xruns recorded with Jack. Then in the OBS case, when I used the specific JACK client (as a secondary test), I wired the system:capture to whatever client came up with OBS. In hindsight, maybe that was a mistake, and I should have instead wired up the JACK sink's front-left/right instead of system capture?
      - fundamental 8y ago
        It looks like HN's reply limiter has kicked in preventing further replies, so I'd recommend shifting discussion to one of the resources I've already mentioned. Based upon your most recent comment it is still not clear if jack is connected to the desired device or not. I'd recommend connecting a simple waveform viewer e.g. http://baudline.com/ http://baudline.com/ to system:capture to see what's going on with respect to what jack sees as its input.