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Just Overall Lost

I was struggling to compile the .tar.gz (on Linux Deepin 15.3) but found qtractor in Synaptic Package Manger, so that's all good now. I've spent a heap of time on qTractor and qJackCtl. Also looking at resources and guides but I'd really appreciate some specialized help.

My goal is to use qTractor to record vocal covers. I require web browser audio (/ all normal audio) to work simultaneously.

My gear is: Scarlet 2i2 Audio Interface (with monitor headphones), Rode NT1A mic, Linux Deepin and Logitech 7.1 surround (let's simplify it for the moment and forget the 7.1).

I believe my qJackCtl is configured incorrectly. In 'Setup > Interface' I choose the 'hw:USB Scarket 2i2 (hw:2)' (Other settings are default). Chrome or Music player audio doesn't work. I choose (default) PCM options, it does work. Neither show me my NT1A or Scarlet 2i2 in the 'Connect' or 'Patchbay'.

How do I troubleshoot this? Is it conflicting with my regular desktop audio (idk, alsamixer)?

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rncbc's picture

don't despair. :)

the first thing you must acknowledge is that JACK, via one of its front-end which qjackctl is one, does take over exclusive control and access of your sound-card device (Scarlet 2i2) so nothing else will be allowed to make any sound to or from it *unless* its a JACK-aware client application.

so, no dice for web audio or browser audio to work simultaneously whenever JACK is running and owning the sound device. this simple fact is one of the most hideous "features" that newbies are confront themselves when trying to work with JACK.

working around all this is not that easy and the solutions there available are not for the faint-of-heart, so to speak :) but there's hope, don't get me wrong: it's just a matter of well balanced mix of patience, perseverance and good willingness :)

ok. all that to say that what you need is all about making JACK and PULSEAUDIO to collaborate. i'm not a expert on this kind of integration but i've heard of many that do it quite successfully. maybe you wish to make friends with google and start your own journey into that brand new world.

for now, i'll leave you some interesting links for you to start over:

  • JACK Audio Connection Kit|How use PulseAudio and JACK?
  • Jack and PulseAudio Together as Friends - Linux
  • Bluebell / Holger / pulseaudio and Jack
  • Using Qjackctl with jackd and pulseaudio
  • hth.
    cheers

    you probably wis

    xolotl's picture

    Thanks rncbc.
    I might shelf getting system audio to work with JACK until I can get mic input into Qtractor via Scarlet. How can I do this when my mic doesn't appear in QJackctl?
    (screenshot http://imgur.com/a/CPCEv )

    rncbc's picture

    reading from the screenshot you already have system:capture_1,2 connected to Qtractor:Master/In_1,2. that's perfect. however what you mean is that you don't get any signal from those lines, right?

    a. try using alsamixer to tweak the capture controls (mic) up; maybe better to run from a console/terminal as alsamixer -cN, with N=0, 1, 2, ... being the sound-card slot number in effect on your system (probably N=0 for the internal on-board device and N=1 for the Scarlet via USB).

    b. besides that, check on the actual hardware box, front-panel and/or rear-panel, whether there are any hints or controls to get the actual Mic line signal in.

    hth.
    cheers

    xolotl's picture

    Thanks again.
    Yeah I still don't get any signal. I also imported a song and that can't be heard either. Maybe that should be our first step; hearing wav or mp3 of a song in QTractor through my Audio Interface's monitor (headphones)?

    Scarlet is sound card number 2. It "has no controls" in the terminal GUI.

    The actual "box" (Scarlet) has a LINE/INST switch and 2 XLR inputs. Do I need to go ahead and try every combination of input and variation of line / inst? I think its something to do with my QJackctl. Should I change the driver of JACK from alsa? (others don't seem to allow as much) I want it realtime, right?

    rncbc's picture

    so it's not working the least... not even playback.

    i'm afraid you'll have to move on some other forum, maybe one where your particular device (Focusrite Scarlet 2i2 ?) is well understood on the Linux arena. Depending on the firmware versio, i have reports that it works OOTB. look, the 3rd link i gave on the pulseaudio-and-jack subject above is in fact one from a happy Scarlet 2i2 user, Holger Marzen aka. bluebell.

    you can contact him here or on the linuxmusicians.com forum. an alternative would be on #opensourcemusicians IRC channel on freenode.net.

    i hope you can find your way through.

    cheers

    pe. if that is of any help, i'm seeing several recent threads on top, here on linuxmusicians.com / Hardware Support & Discussion, about the subject at hand.

    xolotl's picture

    After must frustration I return victorious. I had to make a file '99-realtime.conf' in /etc/security/limits.d' with the lines:

    @realtime - rtprio 99
    @realtime - memlock unlimited

    Then commands 'sudo groupadd realtime' (it may already exists) 'usermod -a -G realtime yourUserName'.
    You then must log off for changes to take effect.

    You make QJackCtl: would it be possible to detect this problems and prompt to run a script that fixes it? Or even just a helpful error with steps to do it manually.

    rncbc's picture

    take note that qjackctl is a GUI from-end to JACK and the problems in your case are pretty well known although exclusive to Linux (fwiw. qjackctl also runs on macosx and windows ere those settings don't apply ever) and there are some distro cases that some system settings are in fact provided at JACK packages installation time, not necessarily when qjackctl is.

    the information you request may be found in too many sites, being the following just an example:

    hth.
    cheers

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