Not much to contribute here except a small anecdote : I once analyzed Steely Dan's Babylon Sisters (the wav. file) because to me it's one of the best mixes of all time, especially for its air. I was surprised to see there was just a slight, tiny bump above 10-15khz compared to other songs.

Here's the song for reference. Listen to how much air it has, so much that you could fall into the mix and find yourself in the studio.

 

This only goes to show how subjective sound is, but I have to admit that to me the high frequencies in track seem a bit excessive, particularly on the percussive transients, but this is my feedback after hearing it through cheap yamaha hs-8's.

 

Steely Dan was the epitome of the California Smile (tm) eq. But, as many have pointed out, done right it sounds great. You have to match the mix style to the music.

 

I have hs-8's too I use sonarworks tho.

 

Without the rolloff everything hurts and is sounding hard and ugly.
What really matters is the midrange.
A good sounding midrange will make you almost forget that bass and treble are missing. Therefore mixing on Auratones works so well. When the mix sounds very good on the Auras, you switch on the fullrange speakers and

 

Is this what modern music spectral balance look like? looks so bass heavy
(talking about the third picture, izotope's one)