Yes, Micah; as Rick commented, it's the distance from the center of the mid-woofer cones to the nearest room surfaces that determines the extent of boundary effects on frequency response. The distance to the back of the speaker enclosure isn't of any particular significance(except that at least a few inches of "breathing room" should be given to a rear port).
As has also been mentioned, the distances from the cone centers to the floor and two walls should be kept unequal so that the boundary effects don't pile up at one frequency.
