Unfortunately I really donít know my way around the Linux sound system and ALSA as well as I should...
But since playback works, and recording works too but just sounds bad, I still suspect a problem with the recording level and suggest a methodical approach to that before more in depth troubleshooting.
I would still like to hear a sample. If you canít make a short recording available online, you can upload (FTP) it to me (see below).
On alsamixer be sure to use F6 to select sound card, might be listed as Generic USB audio device.
Then F5 to view all controls or F4 for capture controlÖ
Left Right Arrow keys to move to MIC/CAPTURE (assuming of course you are using mike input).
Up down arrow keys to adjust volume. (FYI I am at 70%, 16 dB gain)
IF MM shows at the bottom of the bar graph that means it is muted. Press m key, should show 00 now.
Try autogain on and off: (left/right arrow to that column and press M to toggle it. I have it ON.
On my system Scanner is at about normal listening volume setting and Iím using the speaker jack. This seems to work well. However if I take autogain off and set vol to max in alsamixer then I have to turn the scanner up quite a bit to get decent audio (counter-intuitive).
Itís a shot in the dark but you could try Ďalsactl inití to reset things.
If itís not levels causing the problem and if no one else chimes in then I would post this question in a RasPi or Debian forum focused on sound issues.
Audio sample file..
You can upload to me at ftp://gl.asuscomm.com/sda1/ReadWrite/
Request Password in a Pvt Msg if you need to.