Amplifier stability with very low impedance, high efficiency mid/tweeter section???

I understand that the lower the load the more heat has to be dissipated, therefore the more output devices and heatsinking.  I just thought that it was low frequencies that were responsible for the majority of this demand, not higher midrange and up.  

And yeah the amplifier doesn't care about the SPL rating but it does care how hard it has to work.  And a high sensitivity speaker makes it work less hard for the same SPL.  No?

I am old school. If your amplifier cares about the speaker I say look, you're an amplifier, this is your job, tough luck. If you want it easy go back to school, learn how to be a AVR, nobody cares as long as you have a lot of knobs and switches and stuff. But for now, get on with it.

I did lose one to Amplifier Protective Services but that was before I learned to not let them have a cell phone. Take my advice, make an example out of one, word gets around fast, you won't evert have any amplifiers whining about how hard you work them. Trust me. Haven't heard one word of complaint in 20 years at least now.

To understand this better you need to understand what happens when you have an ideal voltage followed by two impedances.  One of the amp, one of the speaker.

V ---> Z(output) --> Z(speaker)  or for simplicity in a DC world:

V--> Ro --> Rs

You need to understand a little about how the varying Z (or R) will affect the voltage at the speaker.

You also need to understand that Zo/Ro is almost never flat, so the amplifier's output impedance is also changing.  The inability of an amplifier to double it's output as impedance is halved is related to this.

So a 100W amp that can't double all the way down to 2 Ohms will also probably not be able to double at 1 Watt output.

Lol MillerCarbon.  

Erik, I've looked at a bunch of other stereophile measurements of amps.  They all fluctuate in impedance but but it's not by very much, at least most of them.  I guess you would need an amplifier with an output impedance of less the .2 ohms across the spectrum and a beefy power supply/enough output deviced to drive a 2 ohm load safely.  

...low impedance of 2 ohms.  Would this be a problem for most amps? 

It can be a problem. My rule is that if the loudspeaker gets into the 2 ohm range I would want to match that with a very robust amp that boasts about its low impedance performance.