Hi: I do this:
/usr/bin/amixer -c 0 sset Line,0 100%,100% mute capt
/usr/bin/amixer -c 0 sset PCM,0 100%,100% unmute nocap
where -c 0 is my audio card. As you can see, the input controls are set to max level (PCM is set for later reproduction), and capture is on. Then I do
$ arecord -r 8 -D plughw:0,0 > output.file
$ file output.file
output.file: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 8 bit, mono 8000 Hz
But output.file contains only noise (the audio signal has nearly zero amplitude). On the other hand, if I issue the following command,
$ cat < /dev/dsp > /dev/dsp
, I can monitor the input. What am I doing wrong?
Linux kernel 3.2.29
EDIT: the input signal I apply it at the machine rear panel LINE IN connector.