DIY AV cabinet - vibration & sound advice

[tmarkr]

Hi,

Am currently buliding a cabinet that will provide a stand for my LCD screen as well as space for receiver, speakers and DVD player. I'm going for a built-in look (built in to the walls) so it’s a space frame construction (wooden beams with 12mm thick MDF panels)… I'm a bit concerned it might turn into a huge boom-box (excuse the expression!). The cabinet will be about 2.5m long with each front speaker and the center speaker sitting on/in the unit.

I spoke to B&W (M1 system is top of the shopping list) and they sounded unconcerned that there would be any big negative impact on the sound as a result of the cabinet, but I'm not so sure....

Was considering buying some expanding foam or some other vibration dampening substance to try and fill some of the voids in the cabinet and deaden the whole unit from vibration.

Any opinions or advice?! Stupid idea or not?!