Brian was a smart guy. For a designer life gets hard below 500 Hz. It's easy to correct reflections, but at a point frequencies move through walls and can interact with the dimensions of the room.
The first important consideration is coupling. Regardless of the floor, the speaker will perform best coupled to the floor. Using isolation methods are a completely different conversation and offer their own unique set of problems and requirements.
In a perfect word coupling is done and you're listening to music. Not true. Placement becomes critical. There are many options each of which affects bass extension, smoothness of response etc. Depending on the crossover point, say 150 or less, stereo placement is not as critical. Higher, the box would benefit in being between the left/right.
With a low crossover point, the the left of center, left, or corner loaded all deliver different results. Using a series of reference tracks and taking a week to a month to fine-tune usually work. Testing gear is great - but not the only solution.
Other factors we all deal with: Is the floor concrete with something over it? Are the walls single sheet drywall or some other material? What is the spacing of the framing? Is at 2 x 4s or 2 x 6s? Is there an airspace in the walls - regular or large? (Large may exist in basement remodels.) What about isolation? Same with the ceiling.
While few people can build an ideal room, .6 x 1 x 1.6 as a guide, consider volume. Is the sub too small or big for the room? Is the ceiling flat? What is the ceiling height? How many doors? Large openings to other rooms? Windows?
While all of this is overwhelming, great sound can be achieved in most any room with patience. Oh, while we are very committed to the music and would be fine with one chair in the room, we typically have to take into our partner or spouses concerns that can be diametrically opposed to our theoretic goal for nirvana.
I know I've gone on. I apologize for that. But in a perverse way it is half the fun. I think Brian wanted all to share in the adventure that was in his mind. He was a gift, icon, and good man. Today we continue to keep him alive every time we listen to one of his speakers. I think when you find yourself moved by the music, in a way that only music can, that he may just be setting next to us. Happy holidays.
