I got 2 of these to replace a pair of 500w SSL subs, running on a 650W rms amp. When I first got them they didn’t sound any better than the low profile subs I replaced, but after about 15 hrs worth of use they sound twice as good and hit maybe 25% harder (on the same amp). Now that I’ve broken them in I Have yet to hook them up to a 1500w rms amp but I imagine they should take it all.
