speaker placement help, medium sized bedroom

i can't quite picture the room. perhaps you could attach a drawing? anyway...

what's the purpose of this? do you make/mix music, or is this for casual listening? the former has all sorts of rules, the latter is: whatever sounds best.

and if it's the former, would you re-arrange your room to improve the sound situation? are you willing to spend any money on room treatment?

A basic diagram or photo would help. It's almost impossible to say based on a rough description.

Rule of Thumb: Speakers should be set up at head height, symmetrically and angled
in towards the listener at approximately 30 degrees to the centre line (equalateral triangle).

I wouldn't wall-mount them, i know bose do a table top stand.

The way I see it, you've got two choices.

Your listening position can be from the bed, or the sofa. If you choose the bed, then I'd place one on the wall next to the door above the desk, and another above the keyboard close to the closet. It's not ideal, but if you listen at the right angle on the bed, you should get a decent stereo image of sorts.

If you choose the couch, the one above the keyboard close to the closet, and the other near the corner above the desk on the same wall as the keyboard.

I wouldn't worry about wall-mounting the Acoustimass satellites, they don't reproduce low enough frequencies for the wall to come into play with the sound.

As far as the subwoofer goes, it should ideally go a little to the right to the centre of the speakers on the floor. Avoid the corner and try not to 'cocoon' it too much. The Acoustimass bass modules don't take too lightly to wrong placement.