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markJT

Member

Registered: 2018-10-18

Posts: 13

Adding an additional USB input to .asoundrc for use with JACK + Mixxx

Hi all,

I'm trying to add a USB input for audio recording to my existing .asoundrc and jackd configuration for use with Mixxx.

I'm currently inputting through one USB via hardware audio interface Native Instruments Audio 8 DJ, with the .asoundrc configuration pasted below. This allows me to input two channels for my turntables for use with Mixxx.

The problem I'm having is that I also need to add an additional channel to record/broadcast within Mixxx, as at the moment if I were to record from Master, it would capture everything from both turntable channels (ignoring the crossfading from the mixer). So I want to add an additional USB input from my mixer and set this for 'record/broadcast' on Mixxx - with configuration in .asoundrc and jackd.

My current configuration is as follows:

.asoundrc:

    ## Audio 8 DJ, from http://www.native-instruments.com/forum/showthread.php?t=74006 (N_Systems)

    pcm.dj_ch_a { type hw; card Audio8DJ; device 0; subdevice 0; channels 2; }
    pcm.dj_ch_b { type hw; card Audio8DJ; device 0; subdevice 1; channels 2; }
    pcm.dj_ch_c { type hw; card Audio8DJ; device 0; subdevice 2; channels 2; }
    pcm.dj_ch_d { type hw; card Audio8DJ; device 0; subdevice 3; channels 2; }

    pcm.dj_8 {
    type multi

    # bind hardware devices
    slaves.a.pcm dj_ch_a
    slaves.a.channels 2
    slaves.b.pcm dj_ch_b
    slaves.b.channels 2
    slaves.c.pcm dj_ch_c
    slaves.c.channels 2
    slaves.d.pcm dj_ch_d
    slaves.d.channels 2

    # bind channels to virtual device
    bindings.0.slave a
    bindings.0.channel 0
    bindings.1.slave a
    bindings.1.channel 1
    bindings.2.slave b
    bindings.2.channel 0
    bindings.3.slave b
    bindings.3.channel 1
    bindings.4.slave c
    bindings.4.channel 0
    bindings.5.slave c
    bindings.5.channel 1
    bindings.6.slave d
    bindings.6.channel 0
    bindings.7.slave d
    bindings.7.channel 1
    }

And to launch jackd I use the following within a systemd unit file:

jackd -S -R -d alsa -p 64 -n 3 -r48000 --device dj_8 -i 8 -o 8

Within Mixxx, this allows me to set my sound API as jack and find the two turntable as I/O for channels 1-2 and channels 3-4.

Now, when I plug in my mixer via USB, the results of aplay -L give me the following additional lines in the output, showing the mixer source:

    sysdefault:CARD=CODEC
    USB Audio CODEC, USB Audio
    Default Audio Device
    front:CARD=CODEC,DEV=0
    USB Audio CODEC, USB Audio
    Front output / input
    surround21:CARD=CODEC,DEV=0
    USB Audio CODEC, USB Audio
    2.1 Surround output to Front and Subwoofer speakers
    surround40:CARD=CODEC,DEV=0
    USB Audio CODEC, USB Audio
    4.0 Surround output to Front and Rear speakers
    surround41:CARD=CODEC,DEV=0
    USB Audio CODEC, USB Audio
    4.1 Surround output to Front, Rear and Subwoofer speakers
    surround50:CARD=CODEC,DEV=0
    USB Audio CODEC, USB Audio
    5.0 Surround output to Front, Center and Rear speakers
    surround51:CARD=CODEC,DEV=0
    USB Audio CODEC, USB Audio
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
    surround71:CARD=CODEC,DEV=0
    USB Audio CODEC, USB Audio
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
    iec958:CARD=CODEC,DEV=0
    USB Audio CODEC, USB Audio
    IEC958 (S/PDIF) Digital Audio Output
    usbstream:CARD=CODEC
    USB Audio CODEC
    USB Stream Output

I believe I need to add details for this into both .asoundrc and my jackd launch script, but I'm having trouble configuring this.

Any help or steer very much appreciated - thanks.