hey guys. i just bought my first pair of senns. (other than that i have only a pair of porta pros and some sony studio set) i got the HD 428's at best buy for $80. yesterday. plugged it into my ipod and listened for a while, the first thing i noticed about this set is the scence of space you get.... then the crystal clear highs and mids. but then, when the song changed to citizen soldier i heard crackling during some high notes. and which made me turn the volume down. is this crackling a defect in the set? or did i just have the volume up to loud? other thoughts on these? thanks for the help!