Greetings, I'm picking up this previously enjoyed unit to-day and it will be married to an upgraded Denon 5800. The spec on the SUB2 says it goes to 21hz +-3 a Sunfire 500w amp, 2 10" drivers and separate controle box. I have 3 questions please. 1. In the speaker setup the Denon asks "Do you have a THX ULTRA 2 sub or one that goes to 20hz. What should I answer here? 2. Since the Denon wants controle should I use the separate controle box? 3. I have a relatively small room 15'd X 10-12'w X 8'h, since I will not be running the volume anywhere near max will it help the juice at the bottom end or does volume have nothing todo with the spec? Thanks, Peter m.