Housing Floorstanders in Cabinets

As Marty says you need to make a seal and a smooth transition between the front baffle and the edge of the cabinet and you need to ensure the cabinet is as flat or as wall like as possible. Any gaps or any sharp edges will create edge diffraction. You can see an example on my virtual system of how to minimize edge diffraction by building a tight fitting frame around the speaker to snugly fit.

Minimizing edge diffraction and ensuring the enclosed space you create is well sealed and stuffed with acoutic fibreglass is critical. The cabinetry needs to be extra thick walled heavy mdf and heavily braced using shelving - as anything loose or flimsy will rattle or create unwanted resonances. If the cabinets are left hollow then this is bad - make sure everything is stuffed with books or jewel cases, dvd's etc. as completely hollow spaces can resonate.

Note that a soffit mount is akin to placing your speakers close up against a wall and you will get some bass boost which can be beneficial (gives you more dynamic range) but may also be detrimental in the form of too much bass or excessive room modes.

Thanks for the responses.

Shadorne, I'll looked at the pictures of your virtual system, it's very nice! My goal is to achieve something like you have...a cabinet that hides the system and looks like it could be part of a library. I'll keep in mind the advice.

You'll need to modify the cross-overs or add a shelving high-pass filter to compensate for the bass through lower mid-range boost.

Receivers with Audyssey will correct for this. Room correction systems like Lexicon's should accomodate it.