I have owned many of the Sennheiser models, keep moving up the line, and have enjoyed each one. I had a hard time deciding between the hd600 and the hd650, but after many , many reviews and trying both I went with the 650's, had a little more bass, and rolled of the treble just a tiny bit but to me, it helped to make the 650's to be able to sit on my noggin for hours on end enjoying the experience. Moving up to the Ember headphone amp, was the finally piece of the puzzle. Tried several different tubes, before settling on one in particular that opened up the soundstage and had the smooth verlvety sound I graved. Vocals are just sensational. Almost had the wife leave me, listening to Diana Krall, was unreal. Did not want to turn off amp.
