Subwoofer

the other issue is whether the money spent on the sub and crossover would be better spent on better speakers. For the Vandersteen example, the 3A Sig + Sub costs the same as the Treo...

Lowest bass string frequency is 41.2Hz.  Lowest piano key is 27.5Hz, but it is seldom used.  My speakers go down to 30Hz.  I would spend money on the sub only for the "Movie Theater" special effects, but it is low priority for me.

jl35,
yes, that is my question...whether money is better spent on better speakers? I added dual JL Audio F110s and the JL Audio CR-1 crossover to my system. Adding the subs has opened my system up. Music has more detail, air, and a larger soundstage. I don't think spending 9K more on speakers would yield the same benefits, but I'm always open to opinions.

My speakers go down to 27 hz, but with the subs I'm hearing bass details that I've never heard before. My system is 2 channel only.

I think there's no question you will get deeper and better quality bass with a high quality sub and crossover...