Live sound mixing (distorted mic sound)

[technician]

I had a gig last night, with bands and "rappers". I own a bit of sound, and mainly work with dj's so mic's aren't my thing. I've worked with them an extremely limited amount of times. But besides that, I know a lot about sound in general. so here it goes:

The rapper guys all used sm57 or 58's, which is the standar for such thing obviously... but a few of the guys sounded "muddy" so I removed some low end, and it still sounded muddy/dirty... It makes no sence to me why it sounded like that. "muddy" is usually too much low end, so I cut lows and boosted high's and it was still muddy... so, what do people do in this situation, or do before hand to prevent this? Is it certain voices? could it be a bad mic? anyone?

thanks in advance

[katoramone]

Dude I am the owner of the PA, and soundman for this place http://www.pub340.com and what I can tell you off the top of my head is this, if you rolled off bottom (which should be ok at unity) and it was still muddy/distorted then I'm 99% shure that you had too much gain and was overloading the consoles pre-amps. The problems I have with SM57-58's is the lack of dynamics so to get the performer loud enough the gain is usually driven hard. Sounds tooooo simple, but Beta mics fix this by adding about 12 to 15 dB more gain without turning the knob. Yes they are pricey but the APEX 381 is just as good (acually has a better capsule and body) and is affordable. Now I'm assuming you dont have any outboard compressors or EQ's clipping and that your Power is balanced to your speakers.
I hope this helps...