I am in the midst of testing out a 20-39 PC+ from SVS. I guess I need to understand bass. This sub is plenty loud enough... Are loudness and tactile related in the fact that and increase in one = and increase in the other? So, if you had a PC+ and a PB12/isd 2 playing at the same SPL, they would still both have the same tactile feel. correct? So, in my case, increasing to 2 woofers would not do anything since I already think it's loud enough with 1 woofer at 1/2 gain. Heres another question: 20-39PC+ vs 25-31PC+... I know that the latter would have more SPL, but if I already have the 20-39 as loud as I like, there would be no SPL gain with going 25-31, correct?