My dad listened to my Beyer DT770/250 ( 2005 ) through my LD Mk III with classical music and loved it. I couldn't get him away from the phones. He would like a pair of headphones to listen to classical music now. He doesn't want the fuss of a dedicated headphone amp, so he will be plugging them directly to the stereo amp at his home... so low impedence high sensitivity is a must. He isn't sure about the open/closed aspect yet. He's turning 80, so in addition to a very expensive bottle of brandy, the headphones will be his gift. $500 or less for the phones. I was thinking about the ATH AD900 if he doesn't mind open. Any other recommendations for unamped open phones for classical? Now how about closed? ATH A700? Others? Thanks!