Budget Strategies forTightening up Bass?

By tightening, I mean more focused. I don't have much room to play with re; speaker placement, unfortunately. They are located in corner formed by back wall and hearth. Back
back of speaker = 10" from wall, side of speaker, about 13" from sidewall.

Rcprince-- I tried moving speakers 4" further away from back wall-- seemed to make a difference. Will experiment further.

Cwlondon-- was that "good luck" with my speakers or "good luck" with my marriage??? ;o)
Musiclug-- I will try brass!
RE: speaker cable and power cords, my speaker cable is 20', so upgrading it significantly will, I'm guessing, cost a good deal more than $ 350, but used, maybe not. Any suggestions?????
I've got Transparent Power Link Plus power cords, now.
I'll try borrowing something else from my dealer, see what happens.

I will explore all suggestions. Although I have only so much flexibility to move speakers, there is some wiggle room. I've e-mailed Alan Yun at Silverline and will get to work experimenting with room treatments and footers first before moving on to wire, amps. Thanks to all!

BOB: My understanding is that Alan Yun designs his speakers with tube amplification in mind. At least I've read that somewhere-- that's not a direct quote from him.
As for the room, it's an "open plan", so the livingroom where speakers are located is separated by a half-height wall from adjacent diningroom and open to adjacent two-story entry. A pretty large space.
MICHAEL:I will look into the sub option. As for reinforcing the floor, it's hardwood, suspended. I can't see covering that with plywood.
MAGFAN: I suspect Vibrapods are not the best footer in my case-- I plan to try alternatives.

Bob-- Thanks. Interesting point, which I'll keep in mind. For now, my goal is to see what can be done with the current set-up. If nothing works, then I'll certainly consider changing speakers or amp.

OK... I did move the speakers; I didn't have alot of room to play with, but now, at a distance of 30" from the wall, rather than 10", the bass is much more defined. In fact, it sounds pretty darned good on well-recorded cds. The sounds-stage is deeper and imaging is better. Could it be better? Probably, but I don't have the luxury of a dedicated listening room. I contacted silverline and Alan Yun asserted the speakers are "desiged to be ported" and that plugging the ports "could damage the woofers". Perhaps this is his standard fine-print disclaimer and does not so much represent an actual risk, but even so, I'm not inclined to start stuffing anything into the 17.5's. For me, they were an expensive purchase. I'm still going to try what others have suggested, in addition to speaker placement.I don't think it has to be a black and white, "this" or "that" approach.