Since it was being driven by the AVR the passive sub probably received little of the 180 watts since that would be controlled by the volume knob. The big advantage of the powered sub it that its amp can put out all of its power even at low volumes if need be based only on the content and the signal driving it. Most reciever spec out their power ratings using only a two channels driven condition and when they are really taxed they hit the wall and can't drive bass speakers hard. Even if the receiver spec says 90 X 7 it may be smokin rope.