My personally optimal sound would be Grado signature with a whole lot better bass extension and possibly overall tiny bit more bass in the whole range than what's present but depends on model a bit in them but yea midbass impact is already very good in them so the major thing would be the subbass range.
The thing is what many people are missing that it's not about neutrality really, it's about what your ears wants to hear and I'd be willing to bet if doing a public blindtest between Grados and say Sennheiser HD650, 800, AKG K70x (laid-back corner) on one end and Grados on the other end, more than half would go for Grado sound. I think a lot of people enjoy this type of sound signature when everything is like thrown into your face, it becomes a more intimate and engaging listen, one that can't stop you from foottapping or headbanging to the music which fits especially younger people's preferred listening experience, it's like getting an energy kick out of it, this is also why my "default" config for my custom foobar2000 Dolby Headphone setup mimmicks Grado-esk sound because I know it'll appeal to a lot of people.
In-your-face but airy with a significant bass bump, that's my personal optimal sound signature, unfortunately I don't know of any perfect examples of that, Grado with a significant bass extension fix would be what I'm looking for.
Edited by RPGWiZaRD - 4/10/12 at 7:47am