The problem to solve is to get the Music player Daemon to play properly with pulseaudio

You can check that your copy of MPD includes PulseAudio support by running mpd --version and making sure "pulse" is in the list of supported outputs. this is the case on Ubuntu now so it is just a matter of getting mpd to work well with pulseAudio.

Read more here;

http://mpd.wikia.com/wiki/PulseAudio

Hopefully you will be pointed to something that can help you to configure MPD with pulseAudio.

HUZZAH

Right. arecord was the dodgy looking element here that I eventually found through fusering the sound files (see my question for my process). But I couldn't find what was causing arecord to start as root on boot. Here's how I did that:

1. Run pstree | less
2. In that, type /arecord and press return to find the arecord process.
3. Press up once and you'll see its parent. In my case this was randomsound.

I installed randomsound a few days ago to generate extra entropy (for regenerating /dev/random) using my sound card. I had completely forgotten it was installed and I guess this was the first time I restarted since installing it.

In short sudo apt-get remove randomsound fixed it. PulseAudio can now grab my sound card and I can listen to some trashy europop while I work.