Another review by CNET for the 500s http://reviews.cnet.com/headphones/yamaha-pro-500-blue/4505-7877_7-35590872.html They briefly mention the M100s and HE4s. I think the Denons are much darker and slower with far more sub bass rumble. The Denons also sound smoother. I guess the ultimate sign for me is that I wouldn't sell either the D600s or the PRO500s as I believe they offer something substantially different. But I would like to hear the general...
I havent heard enough headphones to be able to determine how close the models are to each other in the world of headphones. But I would have to say that they dont sound close to each other in my perception. I guess they both produce music.
Any Aussies want to buy these babies I suggest using:
Reason is that it is the same company, but different pricing... i got stung getting them from the second mentioned website :(
I mentioned it before, but if ure having some comfort issues I suggest getting some cotton wool/balls and making long strips of cotton and stuffing the around the inside of the headphone. It makes more room within the can for your ear and might also decrease pressure at the top of your head.