Originally Posted by Bill Fitzmaurice
Where the longest room dimension is 1/2 wavelength. In feet that would be 1130 (feet per second speed of sound) divided by the room dimension divided by 2. For example, with a 15 foot longest dimension 1130/15/2= 37.6Hz. If the room is very well sealed you would have 12dB of cabin gain one octave down at 18.8Hz, though in an average room 6-9dB would be more likely. If you're not going to get cabin gain adequate to fill in the low end to your desired low frequency cutoff with a sealed sub you should go ported. 6dB of EQ boost in the lows doubles cone excursion and quadruples the power draw from the amp.
Thanks Bill for answering his questions. I am away for the weekend and the internet is horrible, lol. Headroom should always be kept in mind if one does not want to exceed the systems capabilities. Good base will always sound better than a system under strain. Bill is corrected about going to a ported sub if there is little boundary gain the room or one needs more subs: it is all about trade offs.
Klipsch RF 7 based HT 7.4, Pioneer SC 35, Acurus 200 Five, Dayton 18 Ultimxa Dual Sub Cab(2), Dayton 18 Ultimax Large Vented Sub Cab (2), on Berhinger I Nuke DPS amps, Samsung BDP F 7500, Asus/My Book Live HPC 4 TB
Yaquin VK 2100 amp, McIntosh XR 5 speakers, Samsung BDP F 7500