Just bought a pair of these for university after saving up for a while (and joined head-fi as a result!). I am no audio enthusiast but there is a huge amount of detail that I can suddenly hear over the XB500's they are replacing. I have a feeling that I am still used to the Sonys though as the P7's are sounding flat at times to me, is this expected or is that because I am only listening to music from youtube on a laptop and am used to heavy bass coming through my headphones?
You're just used to the insane amount of bass from the XB500's. The P7's actually have emphasized bass, but nothing compared to XB500. Keep listening until your ears are used to the more balanced sound.