A single EP4000 amp would drive my 2011 pair of captivators in my room to about 125dB at the listening position on a radio shack SPL meter to dubstep music at my listening position. I wanted more amp because I knew the subs were capable of so much more.
A single Crown XLS-5000 amp should be good to about 5-7dB more according to Gorilla83's comparisons back and forth between the two amps - which he recorded on video at one point.
The EP4000 amp couldn't make the Captivators tap out - even without a HPF (aka a low cut filter) on the frequencies below port tune. The XLS-5000 does require a low cut filter because it can make the Captivator driver lose control at the frequencies below port tune. I've never heard a bad noise in the sense of a clank or a bang or something hitting something with my cap drivers, but if I turn off the low cut filter so that frequencies below 20hz are being sent to the subs with the Crown XLS-5000- I can definitely hear the drivers lose some control on ultra low scenes like WOTW at very high volumes. Engage the low cut filter and all is well again. The Captivator has a VERY strong motor/magnet structure. Most mortal subwoofer drivers being hit with 2500 watts below their enclosure's port tune (which is effectively like playing the driver in open air without a cab) would make one loud bang as a last hurrah. I'm not sure if the new ported Captivator drivers are still the same specs as the older ported cap drivers. Someone said they might have changed - but I never confirmed with Jeff and don't know for sure. At any rate the 2500 watts x 2 from a 5000 watt amplifier would be a good mate.
I've been considering purchasing the Peavey IPR 7500 DSP when it comes out and selling my Crown XLS-5000. My captivator model was original sold with a 4,000 watt amp, and it is the same driver that is used in the orbit shifter which is powered by a 4000 watt amp. The IPR7500 gives me most of that power capability at 2ohms + the built in DSP with HPF functionality. Built in DSPs are nice to remove some of the what if's that go with additional signal components in the mix.
If you go with something more powerful than the EP4000 then you need at minimum a low cut filter.
Something like this out to do the trick
Or I use a Mic2200 for the same purpose. HPF and two band parametric EQ
and I recently purchased a Symetrix 5 band parametric EQ with HPF that I'm toying with, which is a bit more flexible than the Mic2200 with the addition of 3 extra PEQ bands.
Really if you got one of the above as a HPF at minimum and for some optimization of the frequency response at your listening position then the $680ish Cerwin Vega CV-5000 amp ought to do what my Crown XLS-5000 does. (since the Crown XLS-5000 is discontinued and the fire sales are over).
I personally would skip the two EP4000 amps idea. They don't jive with the Cap's that well. You want to drive the captivators at 2ohm stereo on a powerful amp to take advantage of the power handling capability, and the EP4000 just can't do it - so your left at 8ohm bridged mode, which if I remember correctly is still significantly less than the 2ohm stereo power of a CV-5000 or XLS-5000 which is 2,500 watts by 2 at 2ohm.
Never the less ---- 125dB at listening position from a pair of caps on a single EP4000 in my 3,500 cubic foot room is nothing to jeer at - but still you leave a lot of untapped capability in the subs. My pair of PB13 ultras could only hit 115dB at the listening position on the same dubstep songs that day we did our testing and they were double stacked in the corner while the two caps were on either side of my projector screen like in my signature picture hitting 125dB before clipping out the single EP4000 amp. The Crown XLS-5000 takes me into the 130 dB range at my listening position with my pair of caps. How often do I do that---seldom.....But it's a heck of a ride when I do.Edited by Archaea - 11/14/13 at 7:50pm