To join in on the amp argument, I mean discussion
There is more to it than just a published frequency response. Like someone else alluded to a speakers impedance GREATLY changes under load. You do want an amp that can handle the additional current needed for these transients (remember V=I*Z, so if the speakers impedance lowers, current must increase to keep the desired voltage). Of course, we all know that no voltage source is ideal, which is why you do want a good amp such as the ATI AT2000 or AT3000 series, or that awesome looking the Cinenova Grande someone posted. Now, if we really knew the true specs of the Emotiva units and had an identical ATI, Earthquake, etc, I doubt we would hear a difference.An important thing to remember in general is amplifier specifications are seldom truthful and are very hard to compare.
While ATI rates their amps with all channels driven from 20hz to 20kHz, others may rate them with only one or two channels being driven, or over different frequencies, or over a single frequency. There's also companies that do rate their amps with all channels driven (which Emotiva does do this), but they don't tell you at what frequency or over what range (which is basically useless really if you think about it). How much harder is it to drive a woofer at 20Hz compared to driving a mid-range at 8kHz? Apparently a lot harder. Think about how much less movement a midrange driver has, along with it's much smaller surface area. That means much less energy is imparted on the driver to drive it at 8kHz at the same voltage. At least I know my ATI AT2007 will really put out 300 watts into 4 ohms with all 7 channels driven, and have less than .03% THD at 20Hz. There's also a measurement called slew rate which I think is important. It measures how fast an amp responds to a transient to a voltage transient. This seems like it'd be important for high frequencies.
Without a tear-down on youtube showing the brands of components used and the quality of work, I'd never buy a Chinese made amp (IMHO). Especially for $1000+... Compared to a solid american company kind of close to the same price point (only a few hundred more in some cases), I don't see the point unless you really can't spend the extra 30-60% for an amp that has good quality capacitors, properly sized heat sinks, etc... I mean really, look at the cheap Chinese caps in this thing: http://bilder.hifi-forum.de/max/236566/emotiva-xpa-5_28749.jpg
I think they're made by Foshan No. 3 Radio, which has already changed their name, wtf!?! (see this source: http://www.powerpulse.net/story.php?storyID=5322
). Of course, good luck finding any data you can trust on those caps or expecting them to last as long as a good brand. Amps do get hot, and you do want a good branded capacitor. Operating temperature greatly derates the lifetime of capacitors too, so don't forget how the heat sinks maybe undersized to save money. Any manufacturer willing to cut corners there, will cut them elsewhere too.
I also know I can measure the difference between something like the XPA-5 and my AT2007, just looking at the THD difference it is clear we can measure a difference...