I have to disagree with the others about silver interconnects. While copper may sound better in your system, silver is not typically bright and lean sounding. I think when people first started expeimenting with silver cables this may have been the case, but with years of research and trials, silver cables being manufactured by many companies are now equally as smooth as copper.
On the other hand, I have to agree that your speakers are probably the culprit in your system.
On the other hand, I have to agree that your speakers are probably the culprit in your system.