Subwoofer for classical music listener


This is my second post on the subject of subwoofers.
My first post wasn't specific enough.
I listen to classical music 90% of the time.
Are there any classical music listeners out there who have subwoofers?
if there are, could you let me know what you have?
i don't imagine I would need quite as powerful or expensive a sub as those who mainly listen to other types of music, but I may be wrong.

128x128rvpiano
Ahh, I remember the DQ-10's well. I always wanted to try a pair. 
Yes, I know you have the DQ-20's. but it brought back nice memories.
B
Post removed 
stfoth:  Yes, except for lacking deep bass, I was happy with the system before I added a sub (but, for other reasons, was not happy when I hooked up the sub the normal way.)
With the high-pass I started experimenting, alternately physically removing the sub and putting it back into the system.  During this process I sometimes noticed exaggerated highs even without the sub.  That's why I'm suspecting a bad tube may be developing in the preamp.  Alternately, sometimes the system sounds fine with the sub connected.
 I recently had the amplifiers upgraded, so I don't think there's a malfunction there.
It's not an exact science.
 I'm trying to cover all bases.
I apologize in advance.  You are all audiophiles and I'm only a beginner - and a poor one at that.  But I am desperate for some help.  Finding the right speakers and receiver, on a budget, for CLASSICAL music and OPERA is very, very hard.  I have a 13'x13' family room and $600.  I'd like to plug my computer, dvd player, tv, cd player and speakers into the receiver.  Please don't hate me for getting on here to ask for help.  You men/women are music gods and I need some miracle.  I'm obviously poor and don't know a thing. Right now I have Infinity Reference 2000-3 speakers and a Yamaha RX-395 receiver - if I plug my MacBook Air into that it really sounds bad.  I've been listening/watching opera via streaming/dvd on my computer with headphones.  A 3-hour opera with headphones is long.  Anyone care to help?