How good's your hearing

so if you can hear them, you're not deficient in your hearing. 👍

Not really, you may hear the fundamental but not hear the 2nd 3rd 4th harmonics. 

How about 'sense' it as your mind fills in the gaps? I ask because the harmonics start right where the actual range stops.

All the best,
Nonoise

2nd harmonic is double that of the fundamental, so if a piccolo’s fundamental is 4.2khz
2nd harmonic is 8.4khz,
3rd is 12.6khz
4th is 16.8khz
5th is 21khz
6th is 25.2khz
7th
8th
ect
ect

Destroy any of these, and you have destroyed it’s natural harmonic decay, your left with "gaps" in the music, which is a common Class-D complaint, as they have output filters to rid the switching noise that create phase shifts down to 3-5khz. 
Like when you puck a guitar string, it vibrates faster and faster as it decays away, stop it or change it and you've killed the natural harmonic decay.

Cheers George

I feel like chiming in on this one
Obviously the statement about violin highest frequency 600 Hz is totally wrong. Maybe the misconception comes form the fact that the highest "FREE" note you can play on a violin is E5, the fourth string and is around 600 Hz indeed.

The highest "FUNDAMENTAL" note a violin can produce is around 4K, same of the piano for that matter.

As many have noted it's the harmonics that you lose if freq response is not sufficient.

One thing missing from this discussion: the harmonics are what make up the "timbre" of an instruments. So what you are really missing if you don't have enough high frequency is the "quality" of the sound, what makes a violin sound as a violin and different from a flute or whatever.

Having said that the vast majority of readers of this forum would not be able to hear anything above say 12 / 13 K Hertz. So any discussion about 100k etc is snake oil.

So any discussion about 100k etc is snake oil.

Yes if put that way.

But any tweeter capable of doing 100khz, like my Plasma's can, means it's diaphragm is so light (air in this case) that at 20khz it's distortion will be far lower that anything else, with a weightier cone diaphragm. that's why they sound better.

Cheers George