[Jack-Devel] Using USB sound card with Jack

[John Rigg]

On Sun, Jan 28, 2018 at 03:34:08PM +0000, Benny Alexandar wrote:
> Now, I connected USB sound card and it shows the sound card as follows,
> 
> cat /proc/asound/cards
>  0 [PCH            ]: HDA-Intel - HDA Intel PCH
>                       HDA Intel PCH at 0xf7d30000 irq 35
>  1 [HD             ]: USB-Audio - USB Sound Blaster HD
>                       Creative Technology USB Sound Blaster HD at usb-0000:00:14.0-2, full speed
> 
> After starting jack server  using qjackctl, opened terminal and
> ran the following cmd
> 
> $zita-a2j -d hw:HD  -p 1056  -v
> 
> Then in qjackctl connected the graph as shown in the attached picture.
> USB sound card input (line-in) is connected to an audio output from other PC.
> But I can't hear the audio using zita-j2a.
> I mean audio was not heard in PC where zita-j2a is running.
> 
> Anything wrong in the connections, how to debug and check why
> no audio is heard.

Starting jackd from the command line is preferable to qjackctl for debugging.
Use jack_connect to make connections.
Use jack_disconnect to break connections.
Use jack_lsp to show existing jack connections.

Read man pages:
man jackd
man jack_connect
man jack_disconnect
man jack_lsp


John