"Decibel X PRO" is one of very few sound meter apps on the market that has highly reliable, pre-calibrated measurements and supports frequency weightings: ITU-R 468, A and C. It turns your iOS device into a professional noise meter, precisely measures the sound pressure level (SPL) all around you. This extremely useful and beautiful tool will not only be a great tool for many uses but also bring you a lot of fun. Have you wondered how quiet is your room or how loud is a rock concert or sport event? "Decibel X PRO" will help you answer all of those. WHAT MAKE IT GREAT AND STAND OUT FROM OTHER APPS: - Trusted accuracy: the app is tested and pre calibrated for all Apple devices. The precision is matching with real SPL devices - Apple Watch support: see noise level right from your wrist - Frequency weighting filters: ITU-R 468, A, B, C, Z - Powerful, smart history data management: + Recording data can be saved into a list of history records for future access and analysis + Each record can be exported as hi-res PNG graph or CSV text via sharing services + iCloud support which synchronize all history records across your Apple devices + Fullscreen mode to give overview the whole history of an record - Dosimeter with NIOSH, OSHA standards - FFT and BAR graphs to display real time FFT. Those are very useful for frequency analysis and musical tests. Real time predominant frequency is also displayed. - WAVE graph with 2 display modes: Rolling & Buffer - InstaDecibel to capture your dB report overlaid on photos and easily shared via popular social networks (Facebook, Instagram, Messages, etc.). - Support both Portrait and Landscape layouts - Beautiful, intuitive and carefully crafted UI design - Optimized for iOS 11 OTHER GREAT FEATURES: - Standard time weightings (Response Time): SLOW (500 milliseconds) and FAST (200 milliseconds) - Trimming calibration from -15 dB to 15 dB - Standard measurement range from 30 dBA up to 130 dBA - HISTO graph for plotted history of the recorded values - Real time scale level chart - Display Current, Average/Leq, and Max values with both nice and clear digital and analog layouts - Quick reference text to help you compare with real-life examples - "Keep Device Stay Awake" option for long duration recording - Reset and clear current recording at any time - Tap on Max value to reset at any time - Pause/Resume the tool at any time NOTES: - Please do not expect a quiet room reading will be 0 dBA. The range 30-130 dBA is the standard usable range and an average quiet room will be about 30 dBA. - Although all devices are pre-calibrated, custom calibration is suggested for serious purposes requiring higher precision and accuracy. You will need a real external device or calibrated sound meter as a reference, then adjust the trimming calibration until the reading matches with the reference. If you like it or have suggestions, please support us by rating and giving us comments and feedback.