[Thunder Dump]

Originally Posted by Leo_Gibson

You typically use an SM-58 for live vocals because it is omni-directional i.e. it captures sound from all angles so if as singer is moving around (as most do), the mic will still pick up their voice fairly evenly.
You'd use an SM-57 more for recording instruments / amplifiers where you know they're not going to move around much - the benefit here is that the SM-57 mainly picks up what's right in front of it and ignores the rest, so you don't pick up unwanted noise - just what it's pointing at.

This is false. The pattern for both of these microphones is the same--cardioid (the SM-58 is not omni-directional). They both pick up the same--both on- and off-axis. The only real difference is in the ball grille with the foam lining on the 58--it gives a slightly greater degree of pop and wind isolation, and darkens some of the high end above 13K or so. Both are very good at feedback rejection because of the cardioid pattern.