Quote: Quote: Sure.... but if you make the headphones produce an equal balance curve, then in terms of absolute energy (as measured by energy output) reconstitute the equal loudness curve? In my mind, that would be getting the headphones "out of the way". And I know it's level dependent (as shown in the ISO curves above), I can't control for that yet, but I'm sure I could figure it out. Replaygain would be an interesting first step to get a global range value to work from.... I'll check out the Audyssey application. As far as personalizing curves.... headphones are personal enough so if I personalize them to me.... that's not exactly a bad thing . Besides, sounding "right" or "wrong" is dependent on the coloring of the headphones anyway.... And in more practical terms, I don't think that it's physically possible for a headphone to accurately reproduce live frequencies because beyond a certain frequency low point, the actual sound pressure will decay off a headphone faster than it would on a speaker (or live, for that matter). In terms of live performances.... the microphone doesn't impart the equal loudness curve. Our auditory systems do. So the live performance wouldn't be corrected at all.