One thing that past iPhone owners might not have noticed on the iPhone 4 is a change to the equalizer (EQ) feature found under Settings > iPod > EQ. It’s not obvious from just looking at the screenshot, but if you plug a pair of headphones in, start listening to a song, and then change the EQ from Off to something else, you’ll notice that the volume drops. By about one bar on the 16-bar on-screen scale. Reader Butch H. suggests that this…
