How can one set up audio on Arch Linux supporting multiple programs emitting audio at once without creating an asoundrc?

Question

I'd like to set up audio on my Arch Linux system so that multiple programs can access my sound card and emit audio at a time.

Unfortunately, the asoundrc file confuses me in its syntax, presently I have this file:

cm.!spdif {
     type hw
     card 1
     device 0
}

pcm.!default {
     type plug
     slave {
           pcm "plug:dmix" # this is a line is based on https://bbs.archlinux.org/viewtopic.php?id=95582
           # I have also tried pcm "dmix", based on the thread. It failed to get multiple sound processes running simultaneously. 
     }
}

and while one program at a time can emit sound, whenever I try to run audio in another program none is emitted, like running:

speaker-test -c 2

emits no sound when another program is accessing my sound card. It's irritating as I frequently pause audio-emitting programs and start others and my present situation won't let me.

Here is the output of lspci | grep -i audio:

00:03.0 Audio device: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor HD Audio Controller (rev 06)
00:1b.0 Audio device: Intel Corporation 8 Series/C220 Series Chipset High Definition Audio Controller (rev 05)

So my question is, "How can I set this up in a nice, simple and automated way? Is there a program I can install that will set up the audio without a problem?"

Answer 1

There is a nice, simple, and automated way: Just make sure all programs use plughw instead of hw when they specify the audio device they want. That will put an automatically generated dmix in front of the real hw device.

To make this the default, your .asoundrc file should look like:

pcm.!default "plughw:2,0"
ctl.!default "plughw:2,0"

with the correct numbers identifying the soundcard you want (see e.g. aplay -l).

Edit

Yes, the numers are card and device in that order. You can add a third subdevice number if there's more than one subdevice (plughw:2,0,1).