Originally Posted by pokekevin
Right now I can only go down to 37hz and was wondering whether or not going down 20hz was worth it...anyone care to chime in?
Short answer: Yes.
My first sub (DefTech ProSub 200TL) went to 26Hz +/-3dB and thought it dug pretty deep.
My second one (SVS PB10-NSD) was rated at 20Hz +/-3dB and I noticed a significant
improvement in bottom end (and overall performance). 20Hz was unmistakably better than 26Hz.
My third one (SVS PB12-NSD) was rated at 18Hz +/-3dB. The improvement in bottom end wasn't as significant, but there were times when I could tell that it dug a bit deeper. (With that sub, the more significant fact was that it could hit harder and play louder than the PB10.)
My current ChaseHT SS-18.T* subs play flat, loud and clean down to 17Hz. As with the move from the PB10 to the PB12, the improvement in bottom end was noticeable, but not significant. (Overall output, however, was much improved. And the sound quality - tighter / crisper / "bloat"-free - was also an improvement, to my ears, over the previous ported subs.)
(*The performance of my buddy's ChaseHT CS-18.T subs - which, in his ~30% smaller HT room, dig considerably deeper (down to ~10Hz, thanks to incredible room gain) and play considerably louder than my subs - crushes the performance of my subs and makes for a very different, and very impressive, auditory and tactile experience.
All of this to say that, for HT, getting down to (at least) 20Hz is definitely worth it.
IMO, and YMMV.