I'm occasionally gigging in a 60's / 70's band doing fairly lively stuff. Lead vocals shared around between me, the bass player (gentlemen) and a girl lead singer. She's having problems getting the same sort of projection and clarity as us and I wonder if the microphone is a factor. She's using an SM58 - are there other mīcs out there in a similar price range that would be better suited to the female voice? I've no idea about this and any suggestions would be very welcome.

For information I'm using a fairly old AKG Tri-Power hypercardoid and the bass player a Thomann T-Bone MD 85 beta (which to me sounds really good despite budget price)