======Installation of an Equalizer======

Install **Alsaequal** with the following command:
<code bash>
sudo apt-get install libasound2-plugin-equal
</code>
Answer **yes** to all the questions

List the cards available in the system by typing:
<code bash>
aplay -l
</code>
<code bash>
**** List of Peripherals Devices PLAYBACK ****
carte 0: Device [USB PnP Sound Device], périphérique 0: USB Audio [USB Audio]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 1: ALSA [bcm2835 ALSA], périphérique 0: bcm2835 ALSA [bcm2835 ALSA]
  Sous-périphériques: 8/8
  Sous-périphérique #0: subdevice #0
  Sous-périphérique #1: subdevice #1
  Sous-périphérique #2: subdevice #2
  Sous-périphérique #3: subdevice #3
  Sous-périphérique #4: subdevice #4
  Sous-périphérique #5: subdevice #5
  Sous-périphérique #6: subdevice #6
  Sous-périphérique #7: subdevice #7
carte 1: ALSA [bcm2835 ALSA], périphérique 1: bcm2835 ALSA [bcm2835 IEC958/HDMI]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
</code>

I want to use the USB sound card "C-Media USB Headphone Set". This is the "Card 0". The card number (0 in our case) will be used in the next step configuration.

Create a config file asound.conf

We need to connect Alsa and the plugin **Alsaequal**, so that the settings be applied to this plugin. This is done in the file asound.conf. You can create it with this command:

<code bash>
sudo nano -c /etc/asound.conf
</code>

Copy the following content:

<code python | asound.conf>
ctl.equal {
type equal;
controls "/home/pi/.alsaequal.bin"
}

pcm.plugequal {
type equal;
slave.pcm "plughw:0,0";
controls "/home/pi/.alsaequal.bin"
}

pcm.equal {
type plug;
slave.pcm plugequal;
}

</code>

Change the first "0" with your sound card number [plughw:''0'',0].
Save and quit

We must now configure SvxLink so that it uses equalizer:

Edit **svxlink.conf**
In the part Tx1 remplace the line //AUDIO_DEV=alsa:plughw:0// with **AUDIO_DEV=alsa:plug:plugequal**

<code bash>
[Tx1]
TYPE=Local
#AUDIO_DEV=alsa:plughw:0
AUDIO_DEV=alsa:plug:plugequal
AUDIO_CHANNEL=0
</code>

Reboot
<code bash>
sudo reboot
</code>

To access the equalizer settings, type the following command:
<code bash>
sudo alsamixer -D equal
</code>
{{ :fr:documents:alsamixer_d_equal.jpg?nolink&800 |}}

Use the arrow keys on the keyboard, right and left to move up and down to adjust the levels.