Think I found a quirk in DPS volume control in iOS 7.0.2. For the first time (I think) since I installed iOS 7, I was listening to music on my iPhone with my headphones. I noticed that the volume slider has to be moved to around 75% to get the volume level I like. Normally, in prior iOS versions, the slider would be roughly at centre. Just to make sure it wasn’t my imagination, I tried the Apple music app, and the volume slider set to centre was fine. I have volume limit set to off and I don’t use DPS Hear, if that helps.