Originally Posted by Graphicism
Are you sure about that?
Sony SA5000 goes upto 110kHz and is extremely bright and analytical, Sony XB700 goes down to 3Hz and is extremely deep... it has to mean something... whether we can hear it with our ears or not something is picking up on it, be it our bones or water content... it must plays a role somewhere, it isn't purely coincidence when a headphone extends that low it sounds deep or that high it sounds bright...
I think that if a headphone extends all the way to 110kHz, then there's a pretty good chance that it doesn't have trouble reproducing the highest audible frequencies (as a general rule, that means up to 20kHz, usually lower, but depending on the person, maybe slightly higher), so one would expect the treble response to be very audible and sharp... hence the bright sound. Similarly, if a headphone extends all the way down to 3Hz, it would be no surprise to find that it does an excellent job of reproducing the very lowest tones you can hear. When they engineer a headphone in such a way that it has incredible extension either high or low, chances are it's going to sound slanted toward the high or low frequencies, respectively. A pair of headphones isn't going to sound bright just because it is physically capable of reproducing frequencies that lie far beyond the range audible to humans, and thus, far beyond the range present in any recording you might feed to the headphones anyway. But it might sound bright if it extends very high, very cleanly, without the treble roll-off that almost always occurs even in ultra high-end headphones.
My two cents.