the disgruntled Linux surgeon

After lot's of searching, reading, testing, and trial and error, at last I have reached to a working asoundrc config for alsa.

If you don't know what the file is used for here's a heads up:

alsa usually works out of the box, but can be configured to do more sophisticated stuff using a configuration file:
/etc/asound.conf --- system global configuration file
$HOME/.asoundrc --- per user configuration

So why use it? Here's what I use it for; I hate esd and artsd ( the servers that are supposed to allow you to use your sound card in different programs at the same time ).
Not all programs support them, they introduce latency in the sound, and you have to configure each program to use the sound server.
GNOME uses esd, KDE uses artsd, and it is very confusing to when programs just stop producing sound.
Sometimes you have to run esd over artsd to support some programs ( or the other way round ) which introduces more latency and uses more resources.

Now the alsa library is powerful enough to consolidate these functions and make it transparent.
Using the following instructions I have produced sound from mplayer, realplayer, rhythmbox, and esd ( for Gnome''s bells and whistles ), while recording voice at the same time ( either using arecord or gnome-sound-recorder or gnomemeeting's mic test ). Yes full duplex ! I even got wine to work but not sure it will work for you.

First a little disclaimer, it's best you put this file in $HOME/.asoundrc, and if anything goes wrong like the sound stopped working just remove it. Don't blame me for anything it works for me it might or might not work for you.

That said, I'd be glad to help you reach a config that works, since I am originally trying to make a file that works on all computers ( for the LiveCD of course ).

Instructions :
I am using :

*kernel 2.6.10rc2-mm3 : IMHO not necessary as long as you get latest ALSA.
*latest ALSA driver and libraries ( currently 1.0.7 )
*cut and paste inside the dotted line and save it to $HOME/.asoundrc
*RealPlayer needs to be run using "aoss realplayer"
*esd needs to be compiled with alsa support ( dunno about artsd ).
*any program that asks for the alsa device name to use, choose default.
*mplayer can use either "-ao alsa" or "-ao sdl"
*sdl programs like games, usually work just fine
*change wine/winex config to use alsa driver
*the config file is all you need, just change the rates according to your sound card. Mine is a normal 44100Hz, yours could be 48000 ( especially the builtin AC'97 crads ):

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pcm.card0 {

  type hw

  card 0

  mmap_emulation true

}

pcm.!output {
type dmix
ipc_key 1234
ipc_key_add_uid 1
slave {
pcm "card0"
period_time 0
period_size 1024
buffer_size 8192
rate 44100
}
bindings {
0 0
1 1
}
}

#
# DSNOOP output device
#
pcm.!input {
type dsnoop
ipc_key 4321
ipc_key_add_uid 1
slave {
pcm "card0"
period_time 0
period_size 1024
rate 44100
}
}

#
# ASYM duplex device
#
pcm.!duplex {
type asym
playback.pcm "output"
capture.pcm "input"
}

#
# Make the duplex device default
#
pcm.!default {
type plug
slave.pcm "duplex"
}

#
# OSS Compability

pcm.!dsp0 {
type plug
slave.pcm "duplex"
}

ctl.!mixer0 {
type hw
card 0
}

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if it works, Enjoy. Otherwise tough :)