Why is an XA30.5 a bad match for Revel Ultima Salon II speakers?


I actually own Revel M106 speakers right now, but some day, I intend to replace them with full range speakers like the Wilson Sophia II or Revel Salon II.

People say you need a lot of power to drive the Salons. The M106 and Salon II have almost the same sensitivity, and the XA30.5 can play the M106 louder than I prefer to listen (FYI I have a Velodyne powered sub). I guess my ears are pretty sensitive to loud volumes.

Does having all the mass of driving full range woofers into the 20hz range increase or complicate the workload on the amp significantly?

What is it about these speakers and many others that would demand a larger amp even at moderate volumes? My XA30.5 is supposed to be good for about 190W into 4 ohms, but nobody, including Pass Labs, seems to recommend an amp of that size for the Revel Salon II.

If I were to buy the Salons but had no amp budget, would I be better off trading for a more powerful but somewhat lesser quality amp than the XA30.5 such as a Parasound?
sboje
@bombaywalla , your calculations make perfect sense. I was just wondering if there will be any improvement if the OP uses 2 x XA30.5 in a biamp configuration ? I am not talking about bridging the amps to use as monoblocks but actually using proper biamping, whats your take ? Will the amps perform better, with more headroom ?
Gotcha. I am aware of only 3 speaker brands that are purportedly time coherent; namely: Vandies; Green Mountain Audio; and Thiels. Am I missing something? What brand did you have in mind?
you're right - the 3 you cited are time-coherent.
additionally, older Quads, Sanders Sound Systems ESL Model 10 & Model  11, some older Martin Logans such as the CLX or CLZ or CLS (I'm forgetting the exact model number), Eminent Technology LFT-8 (I think this is the model number), Tannoy DMT xxx Mk2 series (I've the DMT10 Mk2 which is a flat 8 Ohms across the entire audio band & is being driven aplomb by my 1977 vintage Yamaha integrated amp. They don't have great WAF but they sound fantastic). 

@bombaywalla , your calculations make perfect sense. I was just wondering if there will be any improvement if the OP uses 2 x XA30.5 in a biamp configuration ? I am not talking about bridging the amps to use as monoblocks but actually using proper biamping, whats your take ? Will the amps perform better, with more headroom ?
Hi Pani,
nah, biamping will still not do it for him. It does relieve the stress on the amp in that instead of 1 amp providing bass to 2 speakers, 1 amp provides bass to 1 speaker only. 
But, this is a class-A amp - it always runs 100% bias & it's well-known that class-A amps have zero headroom. That's just the physics of class-A topology. 
His XA30.5 will still be a 70-80W/ch into the low impedance with a little more current. It will still limit the peak SPLs. It will surely give him music but not what the Ultima Salon 2's are capable of....
For what it's worth, I have the Salon In and the Parasound A31 with an integra dtr50.7 receiver.  The system is beautiful and would not change a thing.
I own the Revel Salon 2s and drive them with an Ayre V5xe amp. The amp is rated at 150 into 8ohms (300 into 4ohms). The Salons are rated with a nominal impedance of 6ohms. The nominal impedance doesn't tell you much - especially if (like me) you listen to lots of music with a wide dynamic range such as classical or jazz. With classical or jazz played from an Aurender source, I can turn the volume control on my Ayre preamp up to about 35 to 40 out of 60 gradations before I get blown out of my big living/dining room with 9’8" ceilings. At those relatively uncomfortable volumes there is zero distortions that I can detect. With rock, those volumes become quite uncomfortable - Sympathy For the Devil or The Immigrants Song at 25 is incredibly loud.i have never triggered the protection circuitry.