I've recently had my iPhone 4 replaced due to a crack in the screen, but the volume output using headphones appears to be quite low. I compared it to my brother's iPhone and the difference is really about 2 to 3 clicks with the volume up button. I don't have any volume adjustments applied in iTunes and neither has my brother, and we've both tried the exact same song. It's not like I have to put my iPhone at full volume but I'd like to have some extra volume left in case I need it. Anyone else with a similar experience and/or solution? For the record: this is not about the call volume, but this is about the volume when listening to the iPod using headphones.