ATC SCM40As sound quality at low voume

shadorne is right - it's about accuracy.  It makes sense if you think about it.  Live music is pretty loud.  Music is written with live performances of real instruments in mind.  Making music that was originally loud sound good at low volumes requires the response to be modified to compensate.  This modification only works at low volumes, though.  Increase the volume to close to realistic levels and it sounds wrong again.

The solution, in my opinion, is to build a system that is as accurate as possible at realistic volume and then use equalization to modify it when you want something other than accuracy.  If you never want to listen at anything close to a realistic volume then speakers that are optimized for low volume listening are fine. 

I just bought a new amp about a year ago and noticed my speakers put a lot of bass out at low volume. It's around 300 or 350 watts into 4 ohms. I relaced an amp rated at 80 watts. Thought it was strange, used to have to put the volume up to begin to hear any bass. Now the balance of all frequencies stays present at much lower volume. I have no idea why this changed but would guess the increase in power. Other difference is my new amp is high current. It stays stable all the way down to a short. Easily drives 1 ohm impedance. There is no doubt powered speakers with active crossovers have much less distortion.

This is something i am very much interested in; that an amplifier that measures well into 1, 2 10 watts and above  measures(or sounds) as well at 1/10, 1/100,...etc.
And yet it's at these low outputs that many of our "audiophile" live and try to breathe.

Many of the things we value as audiophiles, sorry

@dancekerl

Check out Benchmark AHB2

https://benchmarkmedia.com/blogs/application_notes/power-amplifiers-the-importance-of-the-first-watt

Other than the above, Class A is preferred or at least heavily biased Class A with sliding bias. And Class D is getting better every year.