Class D Technology

Cymbals, for instance, sound more "brassy" and less "splashy".  To me it sounds more natural, but it might create false impression of limited extension.

If the switching noise output filter is set at a higher cutoff so to make the amp look to be flat to 20khz on test this will sound hard.
If it's set lower to try to rid most of the switching noise, this will already be rolling of at 10hkz and therefore rid any cymbal harmonics, this will sound more natural but not very extended.
So your compromised either way, the only solution is a much higher switching noise so it can be cut out totally with the output filter without effecting the audio band at all.

Cheers George  

I'll cast a vote with mapman re a D with a Walsh driver.  Although it's just a 'dinky' driving two pairs of my smaller DIY versions, it's a good fit.  As long as I don't get exuberant and crank it to clip, it's amazing to me how well it 'fits' them.

They'll improve as time goes on.  Pretty soon the electronics will shrink to near invisibility and we'll be left with just the interfaces and the radiators.  I'm working on the latter, myself. *S*

Again, switching noise is inaudible, unless anybody can hear 500kHz. Even bats won't hear it.  I'm not sure why is it so difficult to understand.   I addition tweeter's membrane won't move at all.  Personally, I have problem hearing 20kHz.  As for the bandwidth -  in my amplifier it is set to 60kHz -3dB.  Different sound, more tube like, of class D amp can be explained by low TIM distortion, often responsible for the sharp splashy sound (added higher order odd harmonics).  Class D is in fact so clean sounding that sibilants, for the first time, still strong are very clean and wonderful sounding on every record.

Somehow people cannot comprehend that class D amp is purely analog and switching itself is inaudible.  Switching is present all the time - even without input signal.  Place ear against the tweeter and you will hear very low typical amp's hiss - likely much less than with any class AB amp.
From the sitting position nobody will be even able to detect that amp is ON.  

Classe' would top my list.

I recall when I was in college I could hear well to 20khz. I know because I ran tests.

I also found it much harder to get sound that was not fatiguing. This is back in analog days even.

These days I know I cannot hear to that extent which is normal for ears my age. I find listening not fatiguing at all and can listen enthralled for hours and not want to stop. With most any kind of music or recording. Well except the occasional really bad modern loud pop mp3. That’s what its all about. Maybe there is some advantage to getting older after all.

Any young cubs out there still with golden ears out to 20khz? I’d like to be able to associate what people like to listen to with their age and measured hearing  which becomes less extended for all as one gets older. I suspect a big correlation there.