OK, have about 5 hours burn in on the Gratitudes, tried them again-sibilance gone, nice, open, wide sound, good, round, precise bass, good detail. I'm a little surprised by the amount of bass here...while not anemic, and tuneful, notes sharp, a headphone dedicated to EWF, a pop-funk band, would have a bigger QUANTITY of bass. Not as much here as the AT 1K's, but what is here is quality. Gonna burn some more, I already think these are well worth $60-100 or so, probably more (word of caution-many have had quality problems with Monster in the past, though they are supposed to give a lifetime warrantee).
The Gratitudes are in fact a straight rebrand of the Monster Yao Solar, with more accessories and a smartphone control tacked on (this is straight from Monster's customer service, BTW). So Monster figured out the tuning well before Earth, Wind & Fire were ever involved.