Supplemented Grado 225 and AKG Q701 with a pair Beyerdynamic T1 headphones.
With T1 to play in a different league. Subtle, soft and transparent (now I understand what it is ...). The bass is deep and solid, extended treble with a slight emphasis on the top. The soundstage cohesive. Struck by that it never gets sharp or muddled with yet detailed. Sitting comfortably on your head. Can listen long on various recordings without any fatigue in the ears (Grado hook you stand out in an hour).
If you look a few flaws, it is the upper midrange somewhat laid-back compared to Q701, which in turn are exaggerated there. Stretches me sometimes after AKG earphones which has a lovely crispness and drive there that I sometimes miss the T1. Probably the T1 which is the most neutral of them.
Sure they are expensive, but I do not regret a minute I got them.
Update: Train them in the past only with a Violectric HPA V200 but I thought it was missing something. With rörhörlursförstärkaren Decware CSP2 +, it sounds even better, more and better bass and a clearer, more transparent sound in general.