Thanks for the Comments.   Despite having tinitis in my right ear, my hearing is otherwise acute.  Operationally, I can often find detail, such as fingers moving on a guitar's fretwork at very low volumes, but need additional volume to pull it out of the background.  However, when too loud...

I've been a long time user of the ER-4P and recently replaced my old set with  ER-4PTs after the former pair was lost on a business trip.  In use, I typically pair the ER-4PTs with an iPad2 (primary source), iPhone 4S and MacBook Pro using the audio-out jack in all cases.  Almost exclusively I...