Re: [Alsa-user] Trying to get arecord/aplay to work with M-Audio

[Sergei S. <ste...@li...>]

On Sat, 26 Apr 2008 10:10:46 +0200
Takashi Iwai <ti...@su...> wrote:

> At Fri, 25 Apr 2008 20:45:03 +0300,
> Sergei Steshenko wrote:
> > 
> > On Fri, 25 Apr 2008 16:23:06 +0200
> > Takashi Iwai <ti...@su...> wrote:
> > 
> > > At Fri, 25 Apr 2008 16:19:38 +0200,
> > > I wrote:
> > > > 
> > > > At Thu, 27 Mar 2008 01:58:50 +0100,
> > > > Rene Herman wrote:
> > > > > 
> > > > > On 26-03-08 23:57, Bill Unruh wrote:
> > > > > 
> > > > > > On Wed, 26 Mar 2008, Helge Fredriksen wrote:
> > > > > > 
> > > > > >> Ok, here's what I found out:
> > > > > >>
> > > > > >> Since these cards seem to lack the support for doing frequency conversion in
> > > > > >> HW, you simply need to use the alsa plugin
> > > > > >> plughw instead of hw when referring to the card:
> > > > > >>
> > > > > >> arecord -Dplughw:0  test.wav
> > > > > >> aplay -Dplughw:0 test.wav
> > > > > > 
> > > > > > AFAIK, alsa frequency conversion is pretty primative ( linear
> > > > > > interpolation) which produces a huge amount of noise/distortion.
> > > > > 
> > > > > The default is, but if you install the alsa-plugins package (and 
> > > > > libsamplerate) and add a line
> > > > > 
> > > > > defaults.pcm.rate_converter "samplerate"
> > > > 
> > > > Or "speexrate".  This is usually much faster.
> > > 
> > > And forgot to write: you don't have to add anything to asoundrc for
> > > speexrate plugin.  Install it, then alsa-lib will pick it up
> > > automatically.
> > > 
> > > 
> > > Takashi
> > > 
> > 
> > After some web search I see that there are several quality settings for
> > "speexrate".
> > 
> > How does one choose/change the quality settings ?
> 
> Use "speexrate_best" instead of "speexrate", for example.
> See alsa-plugins/doc/speexrate.txt for details.
> 
> 
> Takashi
> 

Thanks.

I've just read

/usr/share/doc/packages/alsa-plugins/speexrate.txt

file and I understand its contents, specifically, the

"
Or, more easily, define a global variable "defaults.pcm.rate_converter",
which is used as the default converter type by plug and rate plugins:

        defaults.pcm.rate_converter "speexrate"

Write the above in your ~/.asoundrc or /etc/asound.conf.
"

part this way:

I can edit /etc/asound.conf file and add, say,

defaults.pcm.rate_converter "speexrate_best"

line anywhere in the /etc/asound.conf file,

Is this understanding correct ?

I read the file on my SUSE 10.3. laptop, hope it's good enough version.

...

I've just discovered there is no /etc/asound.conf file on my laptop:

"
sergei@z61m:~> ls /etc/asound*
/etc/asound.state
sergei@z61m:~>
".

Should I create /etc/asound.conf ? Should it contain just one

defaults.pcm.rate_converter "speexrate_best"

line ?

Thanks,
  Sergei.