This has been a plaguing issue for the Raspberry Pi install of Raspbian (Debian Wheezy) since it was first built. Talking directly to the Raspberry Pi foundation and the Raspbian team has given me no luck.
The issue itself is that the DAC doesn't initialize until it starts playing a song. It then will turn itself off when done, causing another pop. When using this for a pure music player it is infuriating to say the least, especially when the pop is loud.
I have heard this on VLC, MOCP and MPD. This has been covered in the Pi forums, but no answers are found: http://www.raspberrypi.org/phpBB3/viewtopic.php?f=38&t=8783
I turn to you at Stack Overflow to see if there is a way to solve this issue. My idea is to initialize it at start-up so the pop only happens when it boots up, though I don't know how to control the ALSA to do that.
Hopefully a solution can be found.
Thanks!