Re: matching amp with speakers
I am surely repeating myself, and I have wasted too many bits trying to describe a meaningful test for amp duty cycle, ever since Bink's great amp shoot out (remember that?).
I was in the trenches watching as amplifier evolved from 24x7, to "how long can you hold your breath", or even shorter full output duty cycles.
Squishy performance parameters like this evolve over time in a give and take with consumers and markets. While we all preferred the robust good old "all day every day" CS800, that robust performance cost money for more aluminum heat sinks and more copper/iron in the transformer than absolutely necessary (for music). When customers were offered the option of a lower duty cycle amplifier for less money, they jumped on that with both feet. So the race to the bottom was on, and Peavey had to capitulate to the new paradigm or give up market share to competitors who were already leaning out the window.
Some may recall the CS800"x" that over-night changed from 800W to 1200W output power simply by swapping out the fuse for a resettable breaker, and opening up the current limits in the output devices. This clearly gave it more short term power, but not one iota more long term power. The rest is history, and the markets hav embraced these lower duty cycle amps because they mostly work for typical applications, so why pay for more amp than you need?
While I can point to which manufacturer did it first, I can not blame them for giving the customer what they wanted , even if the customer didn't know that they wanted it yet. 
This will remain squishy, and every new value amp probably needs to be vetted in the real world to see how well it works for typical applications. I am optimistic that modern technology has dramatically scrubbed off a lot of aluminum and iron, without compromising amp power, somebody will always be testing the margins of how much can they cut and still be acceptable for mainstream use.
Professional users will always gravitate to more professional amps that do not test these performance limits so aggressively. This higher duty cycle is a feature that professionals willingly pay up for.
JR
