It sounds like you frequent some questionable venues. You'd be hard pressed to find many live sound engineers operating today that won't be working with a dual

It sounds like you frequent some questionable venues. You'd be hard pressed to find many live sound engineers operating today that won't be working with a dual channel RTA (Smaart, or similar) and keeping an eye on the venue's transfer function during a gig as the acoustics change (different crowds, temperature etc).