This is for a site that previewing songs while browsing will be essential.
Possible locations for music player:
- Glued to top
- Floating top bar
- Floating bottom of window
I would have said glued to the top - because the top is where I would expect to see things that stay in place through the site. However, if you want the player to continue playing as you browse across the site, you will have some interesting challenges anyway!
I would also make sure that it has a "small" version, when something is playing, just the basic buttons, and a "large" form to select a song from. The small form is then less of a problem to locate.
Wherever is easiest to turn it off.
EDIT (after better description of usage)
Have a play icon next to each play-able track. When the song is playing, toggle it to a pause or stop icon. Example with songs 2 & 3 available for sampling and 3 currently playing.