Hearing Test
Use your headphones, turn the volume to 50% and press pause when you start hearing a sound to see the result.
Hearcules is a mobile app which helps to save your hearing! It measures the sound you are currently exposed to and tells you when you should take a break.
Download for iOS:
http://itunes.apple.com/us/app/hearcules/id543567297?mt=8
http://www.hearcules.com
http://www.facebook.com/hearcules