I am building a home theater in my basement and I have a question about utilizing the Axiom M22i speakers. The wall that I will be projecting my screen on backs to a storage area so I would like to build niches in the wall so that I can set the front of the M22is flush with the wall. My concern is whether I would need to leave the back of the niche open to allow the port to breathe or not. I am not sure what volume of air I need to be able to move behind the speaker. Thanks