Here's my problem: I have a Mackie 808M head (300w per channel) which I run a pair of Yamaha S115-IV speakers. I use this setup in small rooms, and use it for vocals only. When playing bigger rooms 200+ people, it just doesn't have enough balls. Also I'd like to mike the drums and bass in the larger rooms. I wanted to add a couple of subwoofers (500w per side) but I was told that I'd be better off adding two more full range speakers, such as (2) Mackie SRS 1500a's or (2) EAW FR153Z'S with a Crown UT2020 amp. Any suggestions?