Can a subwoofer help a bad recording?

It's possible the Sade and Neko Case recordings have overly accented bass. Probably a better test than listing to thumping would be to play a good recording of a full classical symphony orchestra like Beethoven's Symphony #3 to see if the bass is full bodied or is thin. If thin, it's probably one or more elements in your system. The next step is to try replacing items one by one to see what makes the biggest difference. Try to borrow from friends or a good hi fi store. Chuck

Cfjohn makes some good points and suggestions.

If your Silverlines are pretty much full-range, then, assuming all other components are somewhat equal, I'll venture a guess that more than likely it's your amplifier.

-IMO

Cfjohn, I have played lots of classical and it is a very rich sound. I don't have that big of a collection, but I do have about 30 or so classical CDs to choose from. Are you saying that all(every) CD that I place on my system should have a bass with authority or else it is something on my system? As I write this I am listening to Paul McCartney's Wingspan and it sounds great; rich and full. By the way, I don't play my system very loud. It is a few notches higher that normal conversation.

By the way, I have no friends that share in my insanity.

Not all CD will have good bass. There seems to be more variation in engineering of popular ones which is why I suggested playing classical to determine what your system is capable of. Since they sound rich on your system, something comes to mind since you listen at low levels. The ear doesn't hear low and high notes as well as mid frequencies when played at a low volume. In this case a sub may help give the bass punch you wish.