The HD668b is technically exellent for it's price and in fact much more than its price though in my opinion it is not very musical. It has a v shaped sound signature and the highs can be fatiguing at times which is why I sold mine. The seperation, imaging, clarity and detail were really good though. Dare I say even better than the K240S. It was just not musical in my opinion. I found the Superlux HD660 to be better suited for music though admittedly it is maybe not quite as technically accoplished as the HD668 ie not the same 'wow' factor.