I'm in the process of building an entertainment center, which includes a location for a center speaker. I've used speaker fabric to enclose the front opening. I have a Paradigm CC 370 center speaker, which has a rear port. There is a removable 1/4" piece of birch plywood on the back of the entertainment center (for added stability). Do I need to cut out the back of the center speaker compartment? My understanding is that you need some space behind a rear ported speaker, and if I keep the plywood in place, there will be aprox. 12" from the back of the speaker to the back of the cabinet. Note: If the plywood stays, there will be a small hole in the middle for the speaker wire to pass through.