As I write these lines I hear him via MP3 players Internet radio. He wears super, issoliert outstanding from outside noise and lets little outside. Its sound in classical music, rock and pop is great. No intrusive bass, nothing restricts the space or the frequencies or even falsified. It's just fun with him again strengthened to listen to music. But he also shadow: his leather smell very strong and getting used to, especially in the first few days. The smell reminded me of the plastic as the leather. I got a headache and had to temporarily leave him a few days 'left' are. It is designed for mobile use hard to use (unlike the advertising described). 'Folding' he is not. You can see the earpieces screw, making it flatter. Nevertheless, it remains to groß.Zudem it has no bag factory, like the Philips Fidelio L1. So, where then with him? The 3m-long cable is very stable, but also has disadvantages. It is folded ex works so small together that even after 4 weeks the property is still present, wanting to take this small pack size again. With its 3m it is mobile, even at home on MP3 players, just too long and too stiff. The processing of the AKG K550 is very good. Very stable and his attitude to the head size remains unchanged even during repeated insertion and removal. Conclusion: sound excellent wearing comfort very good. Mobile use: hardly feasible. It has been with the AKG K550 a second class headphones for home, when others do not want to disturb or even do not want to be disturbed. For driving on vacation, what you can pack it in a suitcase, he goes still. But for the daily commute to the office, unfortunately .... no.