From the ALSA wiki
|The FAQs have been reorganized. The new location of this question is FAQ#Can I use several applications at once without the second one blocking?|
Can I use several applications at once? The second program I try to run seems to block until the first one releases the device.
The reason for this is that your soundcard and/or your soundcard driver do not support hardware mixing of multiple streams.
If the Dmix solution does not remedy the problem there is another less ideal solution:
You may use a Sound Daemon such as Jackit http://jackit.sourceforge.net/, Artsd, or ESD; Sound daemons can connect a number of different audio applications to a single audio device, or they can connect application to application. Those applications must be "made aware" or written in such a way as to take advantage of a sound daemon. Sound daemons will be covered in another FAQ -- It should be noted that artsd is the default sound daemon of the linux window manager KDE and most KDE applications are ARTSD aware and use the daemon to "share" audio. ESD is the default sound daemon of the GNOME desktop and most GNOME applications are ESD aware as well.
ACTUALIZATION: Check your alsa versions as it says in FAQ047, maybe you do not need an .asoundrc file for this.