Originally Posted by bigguyca
When compared in dB's, and that seems the relevant comparison, the output of all these ATI amplifiers is similar. It's hard to get excited about a dB or two from an engineering standpoint.
Agreed, from a dB output standpoint when the impedance is around 4 ohms. My concern is about having the headroom and trying to figure out how much is enough. For instance in this case its not so much about "my speakers can play 2 dB louder if I have that extra 200 watts" but more like "for passages where the impedance is lower, and/or for reduced efficiency at the speaker when the coils are hot (power compression), having that extra 200 watts should help me be able to MAINTAIN the same loud listening level".
So IOW its not so much the extra watts for being able to pick up an extra 2 dB, but more about the extra watts to be able to properly maintain loud levels when conditions exist the require more power from the amp, such as peaks or dips in impedance or power compression etc. Does this make sense?
That said, my personal choice is for big amplifiers. I don't think I ever use their full capability, but I get satisfaction in owning them; who knows why. I don't own a Corvette, but I doubt most owners drive 150 mph very often, if ever, but they like owning the beasts.
The car - that's a great analogy. In my case I'd prefer to have the exact amount of power that I'd ever need, without having wattage in reserve that is wasted. That's the challenging part, because without specific tests and data from the manufacturers (or others that have tested) its very difficult to know. So what I think I've learned in this process is that a) its very hard to predict exactly how much you many watts you may ever need beyond what a SPL calculator tells you, and b) to cover all bases people recommend 1.5-2x the speaker max wattage is to account for this overhead and "unknown" amount of watts really needed - and perhaps a fair or large amount of that 1.5-2x winds up never being used but is there for those times (perhaps very short or specific passages etc) when needed.
To be clear: I have no experience with high-end Class D amplifiers. Likely my iPhone, and the audio system in my car use them, but that's my limit of experience. I've read about Class D amplifiers and have a basic idea of how they work...
Thanks. It would be really interesting to audition both types of amps in my room. I am almost tempting to get the speakers in place and try a two channel class D and class A/B rated at the same watts in the room to see if I could hear any differences (beyond would could be EQ'ed) and if one seemed to run out of power before the other... I wonder if others have done so. I have to image they have...