How do I refer to a soundcard so that the name always works?
The precise order in which a Linux system discovers any soundcards can
vary each time the machine is rebooted. This is particularly true of USB
devices. The device that used to be
hw:0 can become
hw:1 after a
reboot, or vice versa. Fortunately, you don’t need to use names like
this, and can instead use a form that isn’t dependent on the order that
the Linux discovers your soundcards.
First, in a terminal window, run this command:
You’ll see output a bit like this:
0 [SB ]: HDA-Intel - HDA ATI SB HDA ATI SB at 0xfcef8000 irq 16 1 [DSP ]: H-DSP - Hammerfall DSP RME Hammerfall DSP + Digiface at 0xfcff0000, irq 20 2 [NVidia ]: HDA-Intel - HDA NVidia HDA NVidia at 0xfe57c000 irq 32
The “name” of each soundcard is in square brackets.
With this information, you can now refer to a particular device as, for
hw:DSP (for the RME Hammerfall DSP in the above example.
Even if the devices end up re-ordered for any reason,
still refer to the same device.
The one case where this fails is if you have multiple instances of the same type of soundcard. This is a much trickier situation to deal with and is covered in detail here.
Where do I use this name?
You can type it into the device name selector in the upper left of
qjacktl’s setup dialog. You can use it as the argument to the
of JACK’s ALSA backend (e.g.
jackd -d alsa -d hw:DSP.