I had heard people talking about HD600 for years so I bought a pair. I didn't want the 6xx/650/660 S etc. I wanted the original. I paired them with a Fiio K7 and I bought a balanced 4.4mm headphone cable. These sound very nice and I can tell they scale spectacularly because the difference from unbalanced to balanaced on the K7 is already huge. Are these headphones for bass heads? No, but if you want pleasant, warm, natural sound with good mid range, these are a classic choice. Just make sure you plug them into a decent amp because they sound bad at line level from a PC a phone etc. 5/5