Boo, I use the Shure SM58 Beta also. I have used it with everything from sub-bass bins to headphones--no pop.
Almost everybody, when they first start e.q.ing sound, uses too much bass on the vocals. Better mixers usually have a little button to filter off excessive bass on selected channels. The PSR9000 vocal settings also can do this.
A friend that I work with some likes the sound of Shure SM57's. They "pop" very easily. You have to use an external windscreen in addition to the internal foam to stop it. Maybe that's why my mic costs 3 times as much??
The mic makes a difference, but most of it is more than likely e.q.
DonM