Speaker upgrade

Bass, Bass, Bass, Bass and Bass and more Bass.
Get three subs (three is better than two in the sub department) and if it's not enough rip the tweeter and put a woofer in it's place.

Ok, we want bass, but the bass that exist in the music, not coloration. We dont need speakers that play below the 30 Hz, instruments dont go there, unless you hear organ music. Even if your speakers go to 25 Hz 0 dB, thoes your room has space to give this frequencies.
I'm not an adept of a sub, if you want better bass change your speakers, dont buy a sub. Inplementing a sub in a audio room is difficult, and most of the time the results are only satisfatory.
The question is - What do you want? Better bass; or as someone put it "room filling impact without boom."

Warrenh, could you please explain the concept - Power plus room nulls avoided - when two subs are used.

Seurat, just got home from a wonderful sushi dinner celebrating a very long, tedious house closing. I'm exhausted. I should have thrown a comma in there, but a couple of killer subs will add the oomph (power) to move the air and avoid the nulls--cancellations due to room paramters and placement of the sub. Get on Audioasylum and plug into nulls and do your homework. I'm beat.
peace,
warren :-)

I appreciate all of the usefull help. I am looking to upgrade my preamp and CD player and am looking at the Mac C200 or C46(among others). As for CD I am less sure but was not planning on a Mac CD player. My experience with subs nasn't been the best. Never heard a well integrated sound. So i am mainly interested in input on speakers. Curious about what the new Thiel 3.7's will bring to the table.The 501's definetly have more weight then the MF 308 amp they replaced so maybe a Mac amp would be a big upgrade.

I meant to say Mac preamp would be an upgrade.

Pete, put your speakers on the short wall, as well. That will work with your subs if you go that way. I used to own a pair of CS1.5s. Let's face it: how much air can you move in a room your size with a 6.5 woofer? It has been my experience two subs each placed near your Thiels should give your room what it needs. Much less expensive option than some of the suggestions. Why did prgrammergeek recommend the 5a, besides being drop dead killer speakers? They utilize subwoofers. Happy listening.