Sometimes when I plug in my headphones, OSX will change the volume to halfway. This is too much. How can I make it so that when I plug in my headphones the volume is lower?
Mac OS X uses the volume you set your headphones to when you last unplugged them (try for example plugging them in, muting the sound, and then plugging them out and - after a moment - back in: the sound should still be muted). So you will have to tune down your volume manually after plugging in to avoid hurting your ears.