The idea was so intriguing that in 2014, the NIOSH hearing loss team evaluated 192 sound measurement applications (apps) for the iOS and Android platforms to examine their suitability and accuracy in relation to professional sound measurement instruments (Kardous and Shaw, 2014). Of the 192 apps the team examined, 10 iOS apps met the outlined criteria for functionality, features, and calibration capability, and of those, 4 iOS apps met our testing criteria. Read more about that study in the blog So How Accurate Are These Smartphone Sound Measurement Apps?