Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

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crocket
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Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby crocket » Mon Jun 24, 2019 5:05 am

I don't have Scarlett Solo, but I am considering buying one.
Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?
If I could, I could flip mute status of monitor output and line output in alsamixer so that only one of them is mute at any moment.
This way, I can make it switch between speakers and headphones with a keyboard shortcut.

Can I do that?

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bluebell
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Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby bluebell » Mon Jun 24, 2019 6:46 pm

No. The Scarletts Solo, 2i2 and 2i4 don't have a builtin mixer/volume that can be controlled by the computer.

The 2i4 has 4 outputs so you could mute them with a software mixer, e.g. jack-mixer. Headphones can be assigned with a hardware switch to 1+2 or 3+4.

  • Assign headphones to 1+2 and speakers to 3+4
  • Connect your DAW to jack_mixer, use 2 output channels
  • Connect one output channel to 1+2, the other to 3+4

Now you can mute headphones or speakers.
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crocket
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Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby crocket » Tue Jun 25, 2019 12:09 am

bluebell wrote:No. The Scarletts Solo, 2i2 and 2i4 don't have a builtin mixer/volume that can be controlled by the computer.

The 2i4 has 4 outputs so you could mute them with a software mixer, e.g. jack-mixer. Headphones can be assigned with a hardware switch to 1+2 or 3+4.

  • Assign headphones to 1+2 and speakers to 3+4
  • Connect your DAW to jack_mixer, use 2 output channels
  • Connect one output channel to 1+2, the other to 3+4

Now you can mute headphones or speakers.


What is jack_mixer? Is it a JACK application? I'd like to avoid JACK because it is not supported by web browsers. A bridge between ALSA and JACK introduces pops. I don't like it.

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bluebell
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Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby bluebell » Wed Jun 26, 2019 4:11 pm

crocket wrote:
bluebell wrote:No. The Scarletts Solo, 2i2 and 2i4 don't have a builtin mixer/volume that can be controlled by the computer.

The 2i4 has 4 outputs so you could mute them with a software mixer, e.g. jack-mixer. Headphones can be assigned with a hardware switch to 1+2 or 3+4.

  • Assign headphones to 1+2 and speakers to 3+4
  • Connect your DAW to jack_mixer, use 2 output channels
  • Connect one output channel to 1+2, the other to 3+4

Now you can mute headphones or speakers.


What is jack_mixer? Is it a JACK application? I'd like to avoid JACK because it is not supported by web browsers. A bridge between ALSA and JACK introduces pops. I don't like it.


Sure, jack_mixer is a nice jack application.

Most non-music applicaions like Firefox use Pulseaudio. Having jack as my main sound system and configuring Pulseaudio to output to jack (with jack-sink) works perfectly on my machines. A buffer size of 64 with 48000 Hz is no problem. No xruns when playing Youtube videos.

Note that the Scarletts (and many other class compliant interfaces) run better with 48000 than with 44100.
Linux – MOTU UltraLite AVB – Qtractor – https://soundcloud.com/suedwestlicht

crocket
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Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby crocket » Thu Jun 27, 2019 7:50 am

bluebell wrote:Sure, jack_mixer is a nice jack application.

Most non-music applicaions like Firefox use Pulseaudio. Having jack as my main sound system and configuring Pulseaudio to output to jack (with jack-sink) works perfectly on my machines. A buffer size of 64 with 48000 Hz is no problem. No xruns when playing Youtube videos.

Note that the Scarletts (and many other class compliant interfaces) run better with 48000 than with 44100.


Firefox can use JACK, but it tries to control its own connections. I want firefox to stop controlling its own JACK connections. I submitted an issue regarding that. Firefox also doesn't expose microphone through JACK, yet.

What does buffer size of 64 mean? Is it 64 frames per period?

How can I remove pops from the bridge between ALSA loopback and JACK? I tried alsa_in and zita-a2j.

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bluebell
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Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby bluebell » Thu Jun 27, 2019 4:27 pm

crocket wrote:
bluebell wrote:Sure, jack_mixer is a nice jack application.

Most non-music applicaions like Firefox use Pulseaudio. Having jack as my main sound system and configuring Pulseaudio to output to jack (with jack-sink) works perfectly on my machines. A buffer size of 64 with 48000 Hz is no problem. No xruns when playing Youtube videos.

Note that the Scarletts (and many other class compliant interfaces) run better with 48000 than with 44100.


Firefox can use JACK, but it tries to control its own connections. I want firefox to stop controlling its own JACK connections. I submitted an issue regarding that. Firefox also doesn't expose microphone through JACK, yet.

What does buffer size of 64 mean? Is it 64 frames per period?

How can I remove pops from the bridge between ALSA loopback and JACK? I tried alsa_in and zita-a2j.


My old machine: Intel(R) Core(TM) i5-2500T CPU @ 2.30GHz
Scarlett 2i2, 1st gen

jackd -P90 -p512 -t2000 -dalsa -r48000 -p64 -n2 -Xseq -dhw:USB

No xruns when playing Youtube videos in Firefox -> Pulseaudio -> jackd
About 10% DSP load

What do you use the bridge for? If Pulseaudio is installed then ALSA clients are redirected to Pulseaudio. If you redirect Pulseaudio to jack then everything is fine.
Linux – MOTU UltraLite AVB – Qtractor – https://soundcloud.com/suedwestlicht

crocket
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Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby crocket » Fri Jun 28, 2019 6:26 am

bluebell wrote:My old machine: Intel(R) Core(TM) i5-2500T CPU @ 2.30GHz
Scarlett 2i2, 1st gen

jackd -P90 -p512 -t2000 -dalsa -r48000 -p64 -n2 -Xseq -dhw:USB

No xruns when playing Youtube videos in Firefox -> Pulseaudio -> jackd
About 10% DSP load

What do you use the bridge for? If Pulseaudio is installed then ALSA clients are redirected to Pulseaudio. If you redirect Pulseaudio to jack then everything is fine.


My Gentoo system doesn't have pulseaudio. The bridge is for making ALSA applications output sound to JACK.

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bluebell
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Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby bluebell » Fri Jun 28, 2019 6:54 am

crocket wrote:
bluebell wrote:My old machine: Intel(R) Core(TM) i5-2500T CPU @ 2.30GHz
Scarlett 2i2, 1st gen

jackd -P90 -p512 -t2000 -dalsa -r48000 -p64 -n2 -Xseq -dhw:USB

No xruns when playing Youtube videos in Firefox -> Pulseaudio -> jackd
About 10% DSP load

What do you use the bridge for? If Pulseaudio is installed then ALSA clients are redirected to Pulseaudio. If you redirect Pulseaudio to jack then everything is fine.


My Gentoo system doesn't have pulseaudio. The bridge is for making ALSA applications output sound to JACK.


There's no need to use any tools for that. Just have a ~/.asoundrc like

Code: Select all

pcm.!default {
    type plug
    slave { pcm "rawjack" }
}

pcm.rawjack {
    type jack
    playback_ports {
        0 system:playback_1
        1 system:playback_2
    }
    capture_ports {
        0 system:capture_1
        1 system:capture_2
    }
}

pcm.jack {
    type plug
    slave { pcm "rawjack" }
    hint {
    description "JACK Audio Connection Kit"
    }
}
Linux – MOTU UltraLite AVB – Qtractor – https://soundcloud.com/suedwestlicht

crocket
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Posts: 60
Joined: Fri Mar 29, 2019 11:56 am

Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby crocket » Sat Jun 29, 2019 1:37 am

bluebell wrote:There's no need to use any tools for that. Just have a ~/.asoundrc like

Code: Select all

pcm.!default {
    type plug
    slave { pcm "rawjack" }
}

pcm.rawjack {
    type jack
    playback_ports {
        0 system:playback_1
        1 system:playback_2
    }
    capture_ports {
        0 system:capture_1
        1 system:capture_2
    }
}

pcm.jack {
    type plug
    slave { pcm "rawjack" }
    hint {
    description "JACK Audio Connection Kit"
    }
}


  • I want to switch between speakers(system:playback_{1,2}) and headphones(headphones:playback_{1,2}). Do I need to direct rawjack pcm device to a JACK client that routes its input to either system or headphones?
  • Does ALSA jack client introduce pops in the sound? alsa_in and zita-a2j do.
  • Do I need to place a dmix pcm device on top of rawjack if I want multiple ALSA applications to use rawjack?

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bluebell
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Location: Saarland & Frankfurt, Germany

Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby bluebell » Sat Jun 29, 2019 3:37 pm

crocket wrote:
bluebell wrote:There's no need to use any tools for that. Just have a ~/.asoundrc like

Code: Select all

pcm.!default {
    type plug
    slave { pcm "rawjack" }
}

pcm.rawjack {
    type jack
    playback_ports {
        0 system:playback_1
        1 system:playback_2
    }
    capture_ports {
        0 system:capture_1
        1 system:capture_2
    }
}

pcm.jack {
    type plug
    slave { pcm "rawjack" }
    hint {
    description "JACK Audio Connection Kit"
    }
}


  • I want to switch between speakers(system:playback_{1,2}) and headphones(headphones:playback_{1,2}). Do I need to direct rawjack pcm device to a JACK client that routes its input to either system or headphones?
  • Does ALSA jack client introduce pops in the sound? alsa_in and zita-a2j do.
  • Do I need to place a dmix pcm device on top of rawjack if I want multiple ALSA applications to use rawjack?


  • I have only system:playback_{1,2} on my Scarlett Solo, no headphones:playback_{1,2}.
  • No pops.
  • Never tested it.
Linux – MOTU UltraLite AVB – Qtractor – https://soundcloud.com/suedwestlicht

crocket
Established Member
Posts: 60
Joined: Fri Mar 29, 2019 11:56 am

Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby crocket » Mon Jul 01, 2019 6:25 am

bluebell wrote:There's no need to use any tools for that. Just have a ~/.asoundrc like

Code: Select all

pcm.!default {
    type plug
    slave { pcm "rawjack" }
}

pcm.rawjack {
    type jack
    playback_ports {
        0 system:playback_1
        1 system:playback_2
    }
    capture_ports {
        0 system:capture_1
        1 system:capture_2
    }
}

pcm.jack {
    type plug
    slave { pcm "rawjack" }
    hint {
    description "JACK Audio Connection Kit"
    }
}


With that configuration, mpv, vlc, and mplayer can only play wav files. They feeeze when they try to play mp3, ogg, oga, and so on.

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bluebell
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Re: Can I mute monitor output and line output of Scarlett Solo independently in alsamixer?

Postby bluebell » Mon Jul 01, 2019 2:12 pm

Very strange. I have no explanation.
Linux – MOTU UltraLite AVB – Qtractor – https://soundcloud.com/suedwestlicht


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