I will make this as short as I can. My issue... Maybe I don't have the right amp/source for my T1's...
I own the Beyer T1's , Senn HD650
I sold my Grado PS500. I thought these sounded incredible but sold them as they were very itchy and uncomfortable after 30 minutes of wearing them..
Senn HD650 sound very good. Could sparkle in the highs a little more
Beyer T1's could have more bass and a little less symbalence <spelling>
I think the Grado's sounded better than both with my gear. I am using them with my Marantz PM8004 CD6004 system as this has been better than both my JDS Labs and Bellari HA540
amps. The Marantz has a wonderful headphone out sound.
I am about to sell my Beyer's since I don't really want to buy more gear. However if I can achieve better bass and tone down the highs just a touch with an amp I will.