does a subwoofer kill stereo sound?


I was wondering whether adding a subwoofer to a pure stereo system would cause any harm to the soundstage and other features of the system. What are your experiences? Should one buy a subwoofer to complement a great bookshelf pair (that may be lacking some bass) or necessarily one would have to buy a new par of speakers with deeper bass?
tvfreak
No. Stereo imaging is not impaired by a sub, provided that you've managed the x-over properly. Even if you screw that up, you're probably okay on the stereo separation front, so long as you're crossing resonably well below 100hz.

Marty

PS As Jax points out, a lot of things go easier with subs when there's more than one to work with.
I find the contrary to be the case, provided you have a good sub, properly integrated. The deep bass opens up the sound stage a lot as compared to a stereo that rolls off at ~50hz +, and in no way degrades the stereo separation or imaging.
When I shut my sub off, the stage gets narrower.

Sub is playing well with panels.