Want More Bass

Got a new Rogue Audio tube amp and preamp. (88 and 66 magnum). Used to have a solid-state integrated that seemed to have more bass output. Now, with my speakers (and these components), I long for deeper bass. (My current speaker's bass response is rated at 50hz.) My previous experience with a tube integrated also seemed light in the bass at lower volumes. I listen more at lower volumes than at higher volumes.

So... what are my options:

1. find a new speaker that goes deeper? if so, what is recommended? Budget $3000 max. Needs to be a slim tower design due to room constraints. (Room is 11x17 and speakers are on the 17' wall. Music preference is mostly indie rock, small group jazz and electronica.)

2. add a sub? the preamp has two outs, so I could use interconnects from the preamp. if so, what is recommended. Budget for a sub would be sub $1500.

3. Other suggestions?

Thanks all for your help.