Mike:
I'm glad you're enjoying the 2500s. It's funny that if I do get the 2500s we'll have the exact same headphones: 2500s, RS-1s, and DT-990s!
In my case, though, if the 2500s come then either the RS-1s or DT-990s have to go. Well, ideally I should keep only one TOTAL. Of course, that's what I said when I got the DT-990s! "If the DT-990s come, then either the RS-1s go or the DT-990s go"
hahaha welcome to the Head-Fi Curse...
From what you're saying, though, *maybe* it makes some sense to sell the DT-990s as opposed to the RS-1? I say this because you give me the impression that the 2500s are more similar to the DT-990s than to the RS-1s.
The 2500s are described as "speaker-like", "analytical" (in the good sense), "accurate", and "clean". Meanwhile the DT-990s have a pretty good soundstage and are very detailed (esp. with the highs, e.g. cymbals). I'd say they're colder than the RS-1s, which seems to match some people's impressions of the 2500s. Also, the DT-990s have great bass, but I think they don't quite reach the level of almost physical "impact" that you feel on the RS-1s, especially from bass drums. (I guess in terms of the bass then the 2500s would actually be more similar to the RS-1s, then. Honestly, if they have the same impact that the RS-1s have, I'm pretty much sold!)
On the other hand, the RS-1s are very much in-your-face "headphone-like", and pretty much everyone agrees that they are way more fun and colored than technically "accurate". IIRC, though, people like Zanth will tell you that they nail the tone of wood instruments. Oh, and maybe you don't find the 2500s as comfy as the DT-990s, but I'm willing to bet some money that they're both way more comfortable than the RS-1s (with reversed bowls, which IMO makes them sound their absolute best out of any pads)!
Does this make sense? Maybe there are other people out there that have 2500s + DT-990s or RS-1s that could chime in?
Thanks.