I just wrote up a comparison of these 2 headphones and realized it would be helpful to others. I bought them both to have a battle of the best rock headphones. Here are my findings:
I compared these headphones with the Gilmore Lite amplifier and Cary Xciter DAC. The Gilmore Lite (dynalo) is a perfect amplifier to drive either of them, as it's built specifically for low-impedance headphones. They both have an emphasized midrange. Both a really good with electric guitar. The AD2000's is the fastest dynamic headphone under $1000. I've heard pretty much everything out there and none of the mid-fi dynamic headphones are even close in terms of attack and decay. If you like a midrange centric headphone, you will like this. Bass and treble are both very rolled off. The bass extension is good, but it's just very quiet in the low registers. Timbre is very artificial. Acoustic instruments don't sound realistic. The RS-1 actually has good tonal accuracy. It sounds fairly realistic with acoustic instruments. Bass is not as tight as the AD2000's but much more prominent. The bass is a bit too heavy for realistic acoustic performances, but it's certainly not a bass monster. Kick drums and bass guitar sound great on the Grado. Cymbals can be a bit harsh, but it's not as bad as people make it out to be - the DT880/250, for example, has much more piercing treble than the RS-1. In terms of speed, the Grado is slower than the Audio-Technica. Cymbals get mashed together and drums are a bit blurry. But it's no worse than a HD-600 or DT-880. In terms of comfort, the Audio-Technica is the most comfortable headphone I've ever worn by a long way. The pads are velour and very cushy. The wing system is so light you barely even feel it. The headphone driver covers do touch your ears though, and this can be very uncomfortable for some people. With the RS-1 on flats, the driver grate also touches your ear. I don't find flats or bowls particularly comfortable, but they are tolerable. In my opinion, the RS-1 is a better overall headphone. It is nicely balanced and I prefer it to many other mid-fi headphones. I was expecting a headphone only good for rock, but it's good for all genres in my opinion. The midrange emphasis may annoy some listeners, but not me. The AD2000 does rock very well and is quite fun to listen to. It's flawed, but worth a listen for sure. On some songs I prefer it to the RS-1. The RS-1 has a "grainy" sound with electric guitars, whereas the AD2000 just renders them with super-clean precision. Well, I hope this answers some people's questions about these two headphones.