Do some bass tests and listen to some more tracks. The 7520 cant be touched in bass detail. Not even by the pro. Ever since I had the 7520 I used the same tracks to test every headphone since and not one of them touched it.
What the pro has to me over the 7520 is just about everything else IMO except maybe treble resolution but the pro is less dark or just about the same. Especially timbres which are much more natural and true to nature on the pro. Details are in the same ball park. The 7520 is very much more boxed in by comparison and handles busy music better. If I could have the bass and fit of the 7520 and along with everything else of the pro I would seriously not look for one more portable EVER.
But the Yamaha touched it. Right ?