Sounds like 18″ colossus speakers – I drive mine off a pair of bridged Peavey CS800’s (you can’t drive a pair of stereo speakers off a bridged amp btw, cos bridging makes it a mono amp – essentially turning the stereo pair into one large push/pull mono amp)…
Anything that will give you the RMS power rating basically is good though… C-audio are good, Peavey, Crown etc (I wouldn’t personally go for a Matrix, or a Yamaha because they are too delicate to use on the road for my liking, but you pays your money you takes your choice…)
