i'm going to ask another question here, but this time is little different.
Why sometimes impedance is so different between headphone models and the sound is almost the same?
And how the impedance affect the sound quality?
Let me put some example here:
Koss Pro 4AAT ---> 250 ohm
Koss Pro Dj100 ---> 55 ohm
Akg K142Hd ---->55 ohm
Grado Sr80i (wich are supposed to be the best here) ----> 32ohms
I know that is not like this usually but if we look at this 4 headphones it seems that the headphones with the lowest impedance are the best ones.