TerraTec Aureon 7.1

The Terratec Aureon 7.1 USB is an affordable external sound card which supports optical and digital output through S/PDIF with full 5.1/7.1 surround sound. To use this card, install ALSA (which has support for this sound card). To configure the card for usage, follow these steps:

Set the card as the default device

If you have multiple sound cards, you need to set the Terratec card as a default. Create the following file

/etc/modprobe.d/alsa.conf

options snd slots=snd_usb_audio

Rebooting or restarting the ALSA (sudo /etc/rd.d/alsa restart) may be required for the changes to take effect.

Enable volume control

This card doesn't have hardware volume control, so you need to create software Master control. Create the following file in your home folder

.asoundrc

pcm.softvol {
        type softvol
        slave {
                pcm "dmix"
        }
        control {
                name "Master"
                card 0
        }
}

pcm.!default {
        type plug
        slave.pcm "softvol"
}

Again, restart alsa, then open a music player, play a file and close the player. Then check alsamixer, as you should have a Master volume control.

Hotkeys

The sound card has external hotkeys for volume change and mute. You can capture the button presses by installing Xbindkeys and using the following config:

.xbindkeysrc

#Volume up
"amixer set 'Master' 5+"
    m:0x0 + c:123
    XF86AudioRaiseVolume

#Volume down
"amixer set 'Master' 5-"
    m:0x0 + c:122
    XF86AudioLowerVolume

#Mute
"/media/disk/programs/mute.sh"
    m:0x0 + c:121
    XF86AudioMute

As you can see, alsamixer doesn't handle mute for this mixer, which is why you can use a simple mute.sh script, which stores the volume level in volume.txt. Be sure to change the file path to mute.sh accordingly.

#!/bin/bash
var=$(amixer get Master | grep "Front Left:")
var=$(echo "$var" | sed -ne 's/^[^[]*\[\([^]]*\)\].*/\1/p')
if [ $var == "0%" ]
then
        volume=`cat volume.txt`
        amixer set 'Master' $volume
else
        rm volume.txt
        echo $var > volume.txt
        amixer set 'Master' 0%
fi

Configure mplayer for surround sound (optional)

Add the following codec settings for mplayer

.mplayer/config

ac=hwac3,hwdts,a52,dts,
ao=alsa

I recommend using XBMC for media playback, as most receivers do no support the AAC codec. XBMC will re-encode AAC to a common codec (AC3 probably) in realtime, so you can watch most surround sound media files. XBMC has a self-explanatory configuration system using a GUI.

Tips

To change volume using amixer and hotkeys, use the following command (for example): "amixer set 'Master' 5+"