You don't hear anything below 20hz but you sure as heck feel it. If you're just listening to most music you don't need anything below 30hz. Some organ music drops well below 20hz and lots movie effects go well below 20hz.
For music, I think it all depends on what he listens too here, there is alot of newer stuff like house music that has manufactured bass, as well as just normal artists out there...
Bosso posted this in my thread at AVS.
Sting's A Brand New Day in 5.1 DTS, track #3 "Small World, Big Lie"
People say they don't hear below 20 hz, but I think there are also parts where the resonating freq's add in and contribute to the sound.