Noise Exposure & Hearing Conservation

It's surprisingly easy for your headphones to damage your hearing _ Popular Science.pdf

Sound Measurement

iHEARu User Loudness Ratings of Public and Commercial Locations

*Due to hardware variability in Android and Windows devices, apps should be considered only as "entertainment" and not used for diagnostic purposes. Studies have shown Apple products to better approximate measurements conducted via a sound level meter, but are still not recommended for official sound measurement. (doi: 10.1121/1.4865269)

Excessive noise is known to damage the inner ear. Noise damage is considered permanent and usually preventable!