Well the HD650 is not really suited for rock style of music so i can understand your remarks about them being boring, they are supposed to be laidback sounding afterall.
And no i can't help you out with any of the questions there, haven't heard the PS500 myself sorry
Yes, I tested with about 15 songs, all rock, two pop, and three hip hop.
You mentioned that you heard them all out of the same amp? Did you level match the headphones? Human ears are pretty sensitive and even 1 dB difference will make the same headphone sound much better.
Also did you try them level matched at different SPLs? This is important because different SPLs have different effects on the signature of the headphones.
For example, my Senns don't really shine until I have them up pretty loud. But my SR225i owing to their brighter signature brings out the details enough for lower listening volumes.
They were all connected to a single amp, so when you plugged in your sound source, all 30 headphones on the wall played the music at the same time. All were very similar in loudness, I didn't notice any differences in loudness between them.
I don't even know if I answered your question, because I have no idea what you're asking me. LOL That should give you an indication of my expertise --not much.
Edited by kl237 - 3/14/13 at 9:56pm