Listenbell

Ever wonder how much damage you are causing your ears when you listen to music, audiobooks or videos through headphones attached to your phone? The average cell phone can play maximum sound levels of up to 100 decibels. After listening to a sound at 100 decibels for more than 15 minutes, you are placing your ears at risk for hearing loss.
The increasing prevalence of hearing loss due to audio played at loud levels from personal audio devices such as cell phones is an emerging public health concern. Hearing loss from injurious elevated noise levels is called noise-induced hearing loss. This type of hearing loss is cumulative and can be permanent and irreversible. Even mild or minimal amounts of hearing loss can impact communication, reduce the ability to understand sounds in noisy environments, and can lead to ear pain, tinnitus or ringing in the ears, and muffled hearing. Prevention of hearing loss from excessive noise exposure is the key to enjoying a lifetime to clear and excellent hearing.
Listenbell is an easy to use app that measures the amount of loud noise you are exposed to daily when listening to audio through headphones on your phone. Listenbell uses the NIOSH (National Institute for Occupational Safety and Health) guidelines for safe levels of noise exposure converted to an estimated "dose" of noise based on an average sound output from the phone. You can use this app to monitor whether the volume levels at which you are listening are putting you at risk for permanent noise-induced hearing loss.
With the calibration setting in the app, you can customize the estimated sound level output of your phone if you know the output levels or measure them with a sound level meter.