No sound in ALSA (unable to open slave)

After upgrading to Debian Wheezy and deinstalling pulseaudio I encountered problem with ALSA, specifically with mocp:

$ mocp
Running the server...
Trying JACK...
Trying ALSA...
ALSA lib pcm_dmix.c:1018:(snd_pcm_dmix_open) unable to open slave
Trying OSS...
FATAL_ERROR: No valid sound driver!
FATAL_ERROR: Server exited!

aplay also prints similar messages.

The solution is to create a file named .asoundrc in your home folder and paste this in:

pcm.dsp {
	type plug
	slave.pcm "dmix"
}

Then alsa service should be restarted:

$ sudo service alsa-utils restart

Now mocp should work fine.