If I read more into these posts than I should, my bad. However, I believe the driver contributes more to the sound of a headphone than any other INDIVIDUAL factor by a large margin. If you look at the old Denon line, there is a signature with the same driver used in all three where it has a wide dynamic range from sub bass through a solid high end and all are considered somewhat bright. While there are identifiable improvements along the line as cost increases based on changes in the housing (plastic to wood) and other factors, the common denominator is the driver. The Denon D600 and D7100 have a huge price gap, also plastic vs. wood cups, yet many have described these as having a similar sound due to a shared driver. I believe the same could be said for the HD25 and Amperior where the aluminum cups in the Amperior improve the resonance but don't dramatically change the sound. In fact, when I A/B'd the HD25 Adidas and Amperior, I couldn't tell the difference aside from higher volume on Amperior due to lower impedance. I hope I have provided enough examples to illustrate my unscientific claim that the driver is the foundation upon which every headphone's signature is developed. I welcome thoughts in agreement or to the contrary.