I'm running Kubuntu 10.04, using KDE as my desktop. I've got a headset mic and I'm trying to get it to work so that apps (like Skype, Audacity, etc.) can record from it. So far I'm not having a lot of luck.
Yes, I've made sure that everything is turned all the way up in alsamixer (I've also tried numerous combinations of various mixer elements being up and down -- Mic Boost, Digital, etc.). The best I can do is get some staticky output that resembles the input (e.g. I record for 5 seconds and I say "Hello" halfway through -- when I play it back, there's a burst of static that coincides with when I said "Hello" but it's totally unintelligible, and the rest of the recording is silent).
I've been trying to puzzle out how ALSA works in general, to maybe understand better what it's doing and figure out why the mic won't record sound. One particular question is this:
How do the entries in alsamixer map to the ALSA cards/devices/subdevices, or the devices in /dev? For example, in the "Capture" page of alsamixer there's an entry called Digital. I have absolutely no idea what this is or does. Or, for another example, there's two entries called Capture and Capture 1. Again, I don't know how these entries map to the ALSA devices that are listed with arecord -l or arecord -L.
Here's what devices are listed with arecord -l and -L:
$ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: NVidia [HDA NVidia], device 0: ALC888 Analog [ALC888 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 1: ALC888 Digital [ALC888 Digital]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 2: ALC888 Analog [ALC888 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
$ aplay -l
null
Discard all samples (playback) or generate zero samples (capture)
default:CARD=NVidia
HDA NVidia, ALC888 Analog
Default Audio Device
front:CARD=NVidia,DEV=0
HDA NVidia, ALC888 Analog
Front speakers
surround40:CARD=NVidia,DEV=0
HDA NVidia, ALC888 Analog
4.0 Surround output to Front and Rear speakers
surround41:CARD=NVidia,DEV=0
HDA NVidia, ALC888 Analog
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=NVidia,DEV=0
HDA NVidia, ALC888 Analog
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=NVidia,DEV=0
HDA NVidia, ALC888 Analog
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=NVidia,DEV=0
HDA NVidia, ALC888 Analog
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=NVidia,DEV=0
HDA NVidia, ALC888 Digital
IEC958 (S/PDIF) Digital Audio Output
@@ 2012-01-23 Mon 09:59:31 PST [mattw@gaia - asound]$
I don't expect a simple or quick answer to this; I'm just trying to figure out what might be the problem. I'm certain that the microphone itself works, I just don't know how to get ALSA configured so that it deals with the input properly. (I also have no idea how ALSA/Linux handle connecting the physical microphone input jack to a logical device in the system.) Thanks!
