Can a false or "floating" wall be soundproofed?

[se7enup]

Can a false or "floating" wall be soundproofed?

I have just taken delivery of a 42" Panasonic plasma - and it's the Bees Knees! (and I saved a packet using advice from AV Forums)

My plan is to build a false wall in an alcove next to my chimney breast. The wall will only be arouns 3" deep and will be used to "float" the screen, the left, centre and right speakers.

My neighbour has mentioned that she can hear my set up and although she says she doesn't mind, I'd like to do all I can to maintain neighbourly relations

Would it be possible to soundproof the void behind the wall, rather than letting it become a full height "boom box"

[jolly]

British Gypsum make various soundblock boards that you can stick on the wall, but if you then screw/bolt a floating wall you would have to pass through the soundblock board to the wall behind to achieve a firm fixing
This would diminish a lot of the gains you have made

You could build a stooling wall in front off the existing wall and insulate that and then fix a floating wall on to that, this would be a better solution for soundproofing