As a lefty, I haven't exactly had the chance to play many different basses, but I don't think I've ever come across one with a truly bad B string, either. Exactly how do bad B strings sound and exactly how does the "floppiness" I keep on hearing about manifest itself? Does it mean you can't really hear the difference between the notes lower than, say, Eb if you play the bass unplugged, or does it just mean the string tension is very low so you have to use a lighter touch for the B string than for the other strings? Does it mean the string sounds "dead" and there are fewer harmonics? Sound clips would be cool, too, of course. Now tell me your experiences with bad B strings, if you please.