Sony 7506 and MDR V6 are not the exact same. Sony wanted a little more bass with the V6, Midrange has a bit of a dip and highs not as pronounced. Subtle, but most notice the bass right away. I stand corrected on "flat" for the 7506. I should have said "Very flat with the bass and mids up to 4k" and a bump in the highs from 7 to 10k. It rolls off just at the very high end past 10k. I can't hear much past that anyway and to me, does sound very flat with the bright high end. I too cut the high end -3db around 10k and enjoy them. But bass is flat, not boomy or pronounced.