lots of advice on this board for subs but almost all seem to be geared towards HT - I need something to fill out the bottom end of a 2-channel system where the mains are NHT M5s, which sound great but are not designed to be full range.
Right now I'm looking at something like HSU STF3 or SVS PB1 - I could buy both and test them out head to head in my system and return the one I don't want to keep. They are the both $600. Another option would be to buy the NHT U1 system (sub, amp, x-over) that the M5s were designed to go with, available for around a grand.
I listen to a variety of music, mostly pop but also some jazz and classical, never at very high volumes. What I don't need is a sub that shakes the house. Any opinions appreciated.
Consider REL, too. They are designed with neutral bass extension for music as a priority, and you can switch " on the fly" between speaker-level connection for music and LFE line connection for HT.
"Right now I'm looking at something like HSU STF3 or SVS PB1 - I could buy both and test them out head to head in my system and return the one I don't want to keep."
That sounds like a great solution to me. However, you may want to try the VTF-2 or the VTF-3 instead for the Variable Tuning feature...similar to that of the SVS PB1. The STF series doesn't have this feature.
The fact is, both the Hsu and SVS will provide you with deep, flat and accurate response for music---and if needed, are excellent for HT as well. But, the Hsu is arguably a tad better for music than the SVS, according to various reviews.