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](/index.php/ALSA "ALSA") (which has support for this sound card). To configure the card for usage, follow these steps:

## Contents

*   [1 Set the card as the default device](#Set_the_card_as_the_default_device)
*   [2 Enable volume control](#Enable_volume_control)
*   [3 Hotkeys](#Hotkeys)
*   [4 Configure mplayer for surround sound (optional)](#Configure_mplayer_for_surround_sound_.28optional.29)
*   [5 Tips](#Tips)

#### 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](/index.php/Xbindkeys "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
```

[Kodi](/index.php/Kodi "Kodi") can be used for media playback too, as most receivers do no support the AAC codec. [Kodi](/index.php/Kodi "Kodi") will re-encode AAC to a common codec (AC3 probably) in realtime, so you can watch most surround sound media files. It also 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+`.