Hi, I'm trying to get the best voice recording quality so that I can create Flash demos with Qarbon's ViewletBuilder Pro for Linux (you didn't really need to know that but it's just for background).

Using the built-in mic (or an external mic plugged into the mic socket) of my Dell D600 laptop gives me a lot of hiss and crackle in the background when I play my voice recording back, so an idea suggested was to use a usb desktop mic instead. I'd never heard of these but was told they are pure digital devices and bypass the existing sound card completely, so it sounded promising.

Needless to say the one I bought (Logitech - they only have one model) worked flawlessly under Windows XP but not at all on my Linux system.

Here's my environment and what I've tried/learned so far:-
Novell Linux Desktop beta (based on SuSE Pro 9.1
kernel 2.6.5-7.108
Gnome (whatever the latest version is)
I use the gnome-volume-control to adjust recording levels for the built-in mic/mic socket, so I'm familiar with that
output of /sbin/lsusb (with mic plugged in):-
linux:/usr/src/linux-2.6.5-7.108 # /sbin/lsusb
Bus 004 Device 007: ID 0556:0001 Asahi Kasei Microsystems Co., Ltd
Bus 004 Device 006: ID 058f:9254 Alcor Micro Corp. Hub
Bus 004 Device 005: ID 413c:2002 Dell Computer Corp.
Bus 004 Device 004: ID 046d:c016 Logitech, Inc.
Bus 004 Device 003: ID 413c:1002 Dell Computer Corp.
Bus 004 Device 002: ID 413c:0058 Dell Computer Corp.
Bus 004 Device 001: ID 0000:0000
Bus 003 Device 001: ID 0000:0000
Bus 002 Device 001: ID 0000:0000
Bus 001 Device 002: ID 413c:8000 Dell Computer Corp.
Bus 001 Device 001: ID 0000:0000

when I plug it in /var/log/messages tells me that it has registered driver snd-usb-audio
I read on Google (or here) somewhere that the mic is installed as a second sound card under Windows, so I tried to add a new sound card in YaST, and picked the kernel module usb-audio as the driver. All this looks ok with no errors, but now when I try to record anything the system still uses the onboard stuff.

I guess I need a way to tell the OS that I want to use sound card 0 for playback and sound card 1 for recording?

Any help appreciated.
Chris

Now when you bring up your 'mixer', you should see two 'audio' cards, mute the mic on the sound card 0, and unmute sound card 1.

That's the problem, after pluggin in the mic the mixer doesn't change: I had two "mixers" before and same two after, both of which operate only on sound card 0

One is ALSA SigmaTel and then a model number, and the other is OSS Intel80281

Chris

Sorry, info in my last message was from memory and inaccurate.

The two mixers I get (both operating on sound card 0) are:-
SigmaTel STAC9750/51 [Audio Mixer (OSS)]
Intel 82801DB-ICH4 [Alsa Mixer]

I would have expected an additional mixer to appear once the mic was plugged in, but nothing.

Chris

I also am doing this from memory. I believe that alsamixergui and alsamixer have an option (read the man), to bring up specific sound cards, as in 'alsamixergui -c0' and alsamixergui -c1' and same for the command line I think, 'alsamixer -c0' and 'alsamixer -c1', see http://alsa.opensrc.org/index.php?page=alsamixer .

Also, take a look in your /proc file system for any sound stuff for some clues as to what is really active.
I've found this to be helpful: http://alsa.opensrc.org/index.php?page=TroubleShooting and its parent: http://alsa.opensrc.org/ .

I believe any one of those links above will get you through the trials and tribulations of getting your sound to work. Also understand that usb-audio is a little bit different than 'normal', see http://www.linux-usb.org/USB-guide/x319.html , however if you are seeing the module load, you are doing OK in that respect, so don't mess with the kernal at this point.


Please post any success's you have for future readers.

Hi, sorry for the delay in replying but I've only just had time to do some more troubleshooting.

I have alsamixer on my system and can do alsamixer -c1 which gives me a single slider for mic. volume - PROGRESS!

BUT... still no recording happening.


I don't have alsamixergui so can't try that

Other positive indicators:

/proc/sound has subdirs called card0 and card1

contents of /proc/asound/cards:
0 [I82801DBICH4 ]: ICH - Intel 82801DB-ICH4
Intel 82801DB-ICH4 at 0xf4fff800, irq 7
1 [U0x5560x01 ]: USB-Audio - USB Device 0x556:0x01
USB Device 0x556:0x01 at usb-0000:00:1d.0-1, full speed

contents of /proc/asound/devices:
0: [0- 0]: ctl
20: [0- 4]: digital audio playback
27: [0- 3]: digital audio capture
26: [0- 2]: digital audio capture
25: [0- 1]: digital audio capture
16: [0- 0]: digital audio playback
24: [0- 0]: digital audio capture
1: : sequencer
33: : timer
32: [1- 0]: ctl
56: [1- 0]: digital audio capture

contents of /proc/asound/modules:
0 snd_intel8x0
1 snd_usb_audio


contents of /proc/asound/pcm:
00-00: Intel ICH : Intel 82801DB-ICH4 : playback 1 : capture 1
00-01: Intel ICH - MIC ADC : Intel 82801DB-ICH4 - MIC ADC : capture 1
00-02: Intel ICH - MIC2 ADC : Intel 82801DB-ICH4 - MIC2 ADC : capture 1
00-03: Intel ICH - ADC2 : Intel 82801DB-ICH4 - ADC2 : capture 1
00-04: Intel ICH - IEC958 : Intel 82801DB-ICH4 - IEC958 : playback 1
01-00: USB Audio : USB Audio : capture 1

Somewhere else I read to check the ALSA aliases in /etc/modules.conf, but my modules.conf is 0 bytes.

To me it looks like the hardware is detected and the correct drivers assigned, but that my app isn't using the mic. Do I need to tell my app somehow to use sound card 1 for recording instead of card 0, or is simply enough to mute the mic on card 0 and set a volume for the usb mic?

Chris

For alsamixergui:

http://www.suse.de/en/private/produc...amixergui.html

For Audacity:

http://packman.iu-bremen.de/suse/9.1/i586/

They are probably on the disks that you already have.