Hi:

 I am looking to upgrade my Avant speaker system, but would like to do so piece meal. I have the avant with Dolby capabilities. Thus if I bought the b&o sub now and plugged it in to the back of the avant with no other speakers would it sound ridiculous - unbalanced etc?

Hi, the idea of adding a sub only will be hard to achieve on an Avant, simply because "speaker 1" mode doesn't activate the subwoofer!

Only speaker 2/3/4/5 options activate the sub, but in "speaker 2/4" the TV speakers will be muted, and in "speaker 3/5" you'll get either Dolby 3 stereo or Dolby Digital, so you'll miss the plain stereo performance you should get.

So even if you connect your sub to a front or rear speaker output on the Avant, you won't get the sound you expect..