ESD plays out the first hardware card, as opposed to the "default"
(!default) card alias.

All libasound using programs should be using the default PCM and mixer
stream. ESD is bypassing this behavior for some reason?

This problem can be mitigated by changing/adding the ESD option "-d default"

scott@tara:~$ [0] cat .asoundrc
pcm.!default {
    type hw
    card 2
}
 
ctl.!default {
    type hw
    card 2
}
scott@tara:~$ [0] esd & aplay test.wav
[1] 14494
Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 22050 Hz, Stereo

The esd server starts on the hw:0 card and the aplay is on hw:2.

As originally seen at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=249375