Why are so many headphone makers still putting out crap when it's been more than 20 years since the HD580? You would think they could reverse-engineer that and put it in a cosmetically different frame, if they can't come up with something better themselves. Is there some magic trade secret in the manufacturing process?

By the way, are all the bumps in the 650 treble response real or some sort of measurement artifact? Personally I've found the 580 and 650 treble to be a little irritating and not as refined as a good modern speaker, but I've wondered if it's just "revealing bad recordings" or something.

Headphones have good dynamics without breaking the bank, (as opposed to speakers where you have to pay for quality and for quantity & bass) and they avoid room acoustic problems, but personally I think speakers are generally better. Most are garbage compared to speakers, and the best such as the HD650 still have some flaws. I don't buy this "headphones sound as good as speakers at 10x the price" that people say.

I think it's a shame Sennheiser and others don't offer amps with EQ to fix the Senn midbass hump or other flaws, like solderdude is doing with his Sennator. Bose and others use EQ to improve the sound of their noise-canceling phones as can be seen in the active-vs-passive-mode plots at Innerfidelity. They shouldn't leave it to the customers to cobble together solutions. I would think that EQ would make it simple to fix certain problems, where physical changes to a driver might fix one problem and create others at the same time.