[LAU] Low mic recording level in Ubuntu

[James Cameron]

On Sat, Aug 29, 2009 at 08:37:17PM +0200, peter clarke wrote:
> I have
> (I think) wound up all the levels to maximum in the mixer, but I still
> get only -20dB even with shouting into the mic.

Where are you measuring this -20 dB?  At headphones, or using software?

> It's the same for all hardware (2 internal and 2 USB soundcards,
> different mics), 2 different computers, 2 different versions of Ubuntu
> (Heron on my desktop and Ibex on my laptop) ...

Heron 8.04 is somewhat old.  Try with a Jaunty 9.04 or Karmic alpha 9.10
CD without installing.  Boot from the CD and use arecord or whatever is
available.  Why?  There is a possibility that this problem has been
detected and fixed in a later version.  Also, when these CD images boot
they will use default ALSA levels rather than the levels saved on your
system.

> This started a few months ago (originally, when everything was first
> installed, it was fine) so I'm pretty confident it's an ALSA-related
> software issue.

That's interesting.  I suggest you hide the /var/lib/alsa/asound.state
file and ask ALSA to reset the levels to default.

	sudo mv /var/lib/alsa/asound.state /var/lib/alsa/asound.state.orig
	sudo alsactl restore
	sudo alsactl store

The expected output will vary according to the sound devices you have,
but on a test machine here I get this from the "restore" subcommand:

alsactl: load_state:1579: Cannot open /var/lib/alsa/asound.state for reading: No such file or directory
Unknown hardware: "ICH" "Analog Devices AD1885" "AC97a:41445360" "" ""
Hardware is initialized using a guess method

After you have done this, check your microphone level again.

If you find it fixes the symptom, compare /var/lib/alsa/asound.state
with /var/lib/alsa/asound.state.orig to see where the differences are.

-- 
James Cameron
http://quozl.linux.org.au/