I use to aim the 57 straight at the center and then use another mic on near or around the edge. The 57 straight on has the presence but no bottom adn the outside gets the lows but no matter what i wasnt happy. and i got sick of working with 2 mics. So I tried the 57 off axis around 35-45 degrees against the grill pointing at the center. I've heard people do this and it kind of makes sense the mic sort pointing across the speaker so it wont be as thin as just pointing straight on at center. Someone else told me for heavier stuff they prefer to put the 57 straight on half way between the center and edge of cone... Anyone else have a preference, when using a 57 as your soul mic on guitar cab?