I was a little astonished too but the 500 no matter where I moved it or how loud I turned it up it just didn't match what the 600 ended up putting out. Possibly having multiple 500s would be sufficient but with just a single sub it was lacking.

LFR1100
VP180HP
EP600
M3 In Ceiling x 4
M5OW
M2 - Atmos rears
ADA1500.5
M3 Outdoor Speakers
ADA 1000.8