Originally Posted by mojomike
Re: The Phoenix, I'd very much recommend sitting the sub on a large tile or slab. This sub has an unusual design where the downward ports (boundary-loaded ports) and the surface beneath the sub have a deliberate synergy. If that relationship between the ports and the boundary are changed, the tuning is also changed. This is the key to stuffing such a large driver in a relatively small box and yet being able to tune the sub relatively low. In my opinion, for the sub to play exactly as designed, it should sit on a hard surface without altering the intended distance from that surface.
Ok, so far I cannot tell any difference between having the sub slightly elevated on the carpeting or with the granite underneath it. My frequency response is basically the same, and no audible difference to my ears.
That said, I think that the Phoenix does benefit from a little lift if you have medium to long carpet. I did try it briefly on just the carpet with no lift at all, and although it was not a big difference, I preferred it is lifted with the blocks.
I am keeping it on the piece of granite from now on just because I have it, and because it allows optimal breathing room for the ports that way.
For everyone that is going to place the Phoenix on carpeting, don't worry, Chad has obviously designed it for all placement applications