I'd like to keep the footprint down and want to go with a smaller diameter tube over the popular standard 24" EBS design (what is EBS anyway?) My use will be primarily HT but would like the sub to deliver tight and tuneful bass for musical scores on concert/music dvd's and occasional multichannel SACD. I have a custom DIY sub modeled after the TN1220HO sub with the 12" Hsu driver that does a great job for both HT/music. The HSU is powered by a Parasound 240W/4ohm monoblock and shakes the floor and vibrates picture frames on the wall clear across the house. The Tempest however will for a different room and I'm also curious as to how a Tempest based DIY sub might compare to my TN1220 or an SVS 1646CS+. The Tempest will go in a room approx. 21'x14'x7' with concrete floors. I'm concerned that I won't feel the bass in this room due to the solid floor and not sure about the room effects. I plugged in some numbers quickly with LspCad using the 18" sono using an 8" port and came up with 7.5 cubic feet tuned at 19Hz resulting in a 5 ft Tall 18" sonotube with 8"x36" port with what looked like a flat frequency response beyond 20Hz with 3dB down at 17Hz. Not sure if I did this right and how accurate the model is with freq response especially in my room. What else do I need to consider? I'm not even sure what SPL this thing is gonna deliver and the 8" port is big enough to swallow my cat What do you guys think?