Jose Hidalgo
Addicted to Fun and Learning
95%? That is of course your subjective opinion, but objectively the HD 580 doesn't play in the same league as the HD 600. Need proof? Take a look at Oratory's EQ for the HD 580 : https://www.dropbox.com/s/ed6u2hu3gqg1x83/Sennheiser HD580 precision.pdf?dl=0Try to find a second hand HD580. That'll get you 95% of a HD600 for a fraction of the cost. I think the HD580 represents the best value in headphone audio right now, IF you can find one. I picked mine up second hand for about $70.
He needs -14.5 dB of preamp just to get the bass to decent levels. The HD 600 needs only -5.5 dB.
If the OP is ready to pay large amounts for his system (in the $800 range), we can safely assume that he cares enough about sound quality (and other criteria like build quality and comfort) to not be interested by lesser stuff. We could easily suggest other "cheaper and popular" cans like the Fidelio, really good for their price, but just like the HD 580, they don't play in the same league.
Plus honestly, I don't think it's fair to compare the plasticky thing on top with the more serious metal stuff on bottom. It's like the top one is for children and the bottom one for adults. OK, just kidding but you get my point.