Pros: very relaxed sound
Cons: little rolloff on both ends (treble, bass), compared to the 70x line
Compared to the Q701, K701, D7000 the K501 spend a very relaxed sound to me.
You could here with this headphone many hours without tiredness.
Compared direct with the Q701 I notice a little rolloff on both ends (treble, bass).
A very good headphone for little instrumentation ... e.g. a vocalist and a guitar and for some classic music too.
It's a headphone that headphone »freaks« must have.
Cons - AKG don't made them furthermore, it's obsolete.
I bought it almost good as new and checked by AKG.