I just activated iTunes in my test account, and Hal is correct about where eq. and vol. settings are stored.
The settings are, like he figured, individual user cofigurable, and, in fact, when I dragged ~/Music/iTunes/iTunes Library & iTunes Music Library.xml from my main account to my test account the settings, which came with them, were greyed out. (I first dragged iTunes Library over, and the settings came with it, so they are, indeed, duplicated.)
