https://www.marcelpost.com/wiki/index.php?action=history&feed=atom&title=Sound-alsaSound-alsa - Revision history2026-05-17T04:57:42ZRevision history for this page on the wikiMediaWiki 1.39.17https://www.marcelpost.com/wiki/index.php?title=Sound-alsa&diff=1559&oldid=prevAdmin at 00:27, 29 July 20142014-07-29T00:27:29Z<p></p>
<p><b>New page</b></p><div>ALSA (Advanced Linux Sound Architecture)<br />
<br />
My main focus when I write these pages is on getting sound to work properly with a Raspberry Pi. The techniques in these notes may work on other systems but I have created this page to keep track of RPi related sound information.<br />
<br />
== default RPi (Raspbian) sound settings ==<br />
<br />
<br />
<br />
== disabling the on-board sound card ===<br />
<br />
/etc/modules<br />
<br />
/etc/modprobe.d/modules<br />
<br />
(to be edited..)<br />
<br />
<br />
<br />
<br />
== measuring sound volume input level ==<br />
<br />
* display the current input level of sound presented to the recording device<br />
<br />
<pre><br />
arecord -Dhw:0 -c2 -d 0 -fS16_LE /dev/null -vvv<br />
</pre><br />
<br />
It just starts a recording but sends the recording to /dev/null rather than saving it, and then around every 10ms it spits back a new line which looks like this:<br />
<br />
Max peak (2000 samples): 0x000028ca ####### 31%<br />
<br />
Max peak (2000 samples): 0x00002872 ####### 31%<br />
<br />
Max peak (2000 samples): 0x000023de ###### 28%<br />
<br />
Max peak (2000 samples): 0x00002bf3 ####### 34%<br />
<br />
Max peak (2000 samples): 0x00002cb1 ####### 34%<br />
<br />
<br />
<br />
* display the sound system's gain setting of the input channel<br />
<br />
<pre><br />
123<br />
</pre><br />
<br />
Nothing here yet<br />
<br />
== alsa config ==<br />
<br />
/etc/asound.conf or ~/.asoundrc <br />
<br />
<pre><br />
pcm.!default {<br />
type asym<br />
playback.pcm {<br />
type plug<br />
slave.pcm "hw:0,0"<br />
}<br />
capture.pcm {<br />
type plug<br />
slave.pcm "hw:1,0"<br />
} <br />
}<br />
</pre><br />
<br />
This little ALSA configuration setting uses the default sound card as playback device (hw:0,0) and sets hw:1,0 (that suppose to be your USB-mic) to become the default capture device.<br />
<br />
http://wiki.audacityteam.org/wiki/USB_mic_on_Linux</div>Admin