how to run jack?

DrSlony
2008-11-08
2013-05-28
  • DrSlony
    DrSlony
    2008-11-08

    Hey

    I use a modern up-to-date system. It's a gentoo x86_64, kernel 2.6.25-r7 (alsa), KDE4.

    I just installed rakarrack2 from svn, when I tried running it I got this error:
    JACK compiled with System V SHM support.
    loading driver ..                      
    creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
    control device hw:0                                                     
    the playback device "hw:0" is already in use. Please stop the application using it and run JACK again
    cannot load driver module alsa                                                                      
    no message buffer overruns                                                                          
    Cannot make a jack client, is jackd running?

    I don't know how to start jack properly. I tried "jackd -d alsa" but got this error:
    control device hw:0
    the playback device "hw:0" is already in use. Please stop the application using it and run JACK again

    I tried "jackd -d alsa -C" and it started and ran, but when i ran rakarrack it made no difference to the sound of my guitar. I tried finding a solution in the jack documentation but to no avail.

    I would very much appreciate it if anyone told me how to run jack so that it will work properly in rakarrack. Note that "hw:0 is busy", so if I have to use it, please tell me how to free it up.

    Regards
    DrSlony

     
    • Josep Andreu
      Josep Andreu
      2008-11-08

      Hi

      Jack is a realtime sound server... that means: if you want use jack you need to configure all the apps to use jack .. if you use KDE4 in the KDE Control Panel Sound you can set KDE4 apps to use jackd  as sound server.

      >I don't know how to start jack properly. I tried "jackd -d alsa" but got this error:
      >control device hw:0
      >the playback device "hw:0" is already in use. Please stop the application using it and run JACK again

      Anyway you can see what applications are using your soundcard with the command:

      lsof | grep /dev/snd 

      Stop this apps .... then start jack ..  and then configure this apps to use jack.
      The best way to run and configure  jackd is using qjackctl  ....   I recommend to use with the lowest possible period. By default is set 1024 ...but  with 256 or lowest you will have less latency with rakarrack.

      If you have jack already run ..... you need to start the apss that want to use this jackd server as the same user who starts the server.

      Greetings

      Josep