Thanks for the tips, Wayne. I looked on Wednesday and the speakers are set up like you suggested, so I bet the issue is with the mic itself. I'm not sure about the singer, but I do know that the guitarist uses an omnidirectional lav mic. I'll take your advice about swapping it out for a cardioid. I noticed that Sweetwater sells them. I'll probably go with the Shure brand, since that's the one I'm most familiar, unless you think a different mic would be a better fit.