What does it mean to measure "goodness" in percentages for you?
Well, it is subjective but also reflective in regards how I perceive value in headphones. For me headphones like HE400i or HD 650 are really high value products because of their sound quality/price ratio. When I compared HE400i vs HE1000 v2 (purely in terms of sound quality) my conclusion was like OK HE1000 v2 is better but certainly not 5 or 10 times better.Or in other words HEK is technically the better headphone but of course HE400i screams better value. My main criteria regarding sound quality are following items: timbre/overall tonality, bass, midrange, treble, instrument separation, soundstage, imaging, PRaT/dynamics, musicality and overall transparency/resolution. These are 10 items for sound quality. If I am following the math rule - 10 points as maximum for each item - then the best headphone gets 100/100. Subjectivelly for me HE400i would get around 88% and HEK V2 maybe around 96 or 97% - so close to a perfect headphone. However in terms of value HE400i would get 10/10 and HEK probably "only" 8.5/10 (because of the really high price).