Sound Level & Spectrogram 4+

Measure noise and music easily with your iPhone. Visualize your sound environment with the genuine dB meter app.
*** Free of charge! No subscription! ***

"Sound Level & Spectrogram" is a sound level meter app for iPhone to easily measure the sound level of noise and music in your living environment.

Simply tap the start button to measure sound levels in decibels (dB) and view the real-time variation of the sound level. You can also use the spectrogram feature to visually check the frequency characteristics of the sound source.

Furthermore, you can select between frequency weighting correction characteristics and time weighting characteristics, which are essential for standard sound level meters, enabling appropriate sound measurement.

Exposure to noise can impact health, potentially causing tinnitus, sleep disorders, stress, cognitive decline and heart disease. These risks have also been highlighted by the World Health Organization (WHO).

Understanding noise levels is the first step towards improving your quality of life. Use this app to protect your health and create a comfortable living environment.

Features:
- Sound level measurement (dB): Leq (equivalent sound level), Min (minimum value), Max (maximum value), Avg (time-averaged equivalent sound level)
- Frequency weighting correction characteristics: A (general sound level measurement with auditory correction), C (sound level measurement with almost flatter correction than A correction, e.g. peak evaluation at high volume), Z (flat characteristics without auditory correction, physical sound level measurement)
- Time weighting characteristics: Fast=0.125sec, Slow=1.0sec
- Time course graph
- Spectrogram: 1/3 octave band analysis
- Measurement time: 20 sec

Applications:
- Environmental noise measurement
- Architectural acoustics
- Live sound check
- Installation of audio equipment
- Tuning of sound equipment
- Device management

Example of the noise level situation:
- 130 dB: Engine sound of Airplane
- 110 dB: Horn of Car
- 100 dB: Noise of passing train
- 90 dB: In loud factory
- 80 dB: In the train, Vacuum cleaner
- 70 dB: Noisy office, Noisy Street
- 60 dB: Quiet Car, Normal conversation
- 50 dB: Quiet office
- 40 dB: In the library, Quiet residential area
- 30 dB: Outskirts of midnight, Whisper
- 20 dB: Sounds of rubbing leaves

Note:
- Spectrogram is a tool to analyze the frequency spectrum of sound, with time on the horizontal axis, frequency on the vertical axis, and the strength of the signal represented by colors, and is used for acoustic analysis, voiceprint identification, etc.
- This app is adjusted the reference value for iPhone. However, the built-in microphone of your iPhone is likely to have a non-uniform gain. Therefore, exact measurements are not guaranteed.
- The standard noise measurement range is 30-130 dBA, and the measured value (Leq) is about 30 dBA in a quiet room of the household. Due to the presence of background noise, noise levels are never measured at 0dBA even in very quiet environments. In a typical anechoic room, the noise level is around 5-15 dBA.
- At the initial startup after installing the app, the iOS system asks for permission to access the built-in microphone. In this case, you need to enable access to the microphone. If you have not enabled this setting, this app cannot work by privacy restrictions of the iOS system. Please enable the access permission on the iOS setting, "Settings > Privacy & Security > Microphone".

Please visit our iOS app support page for more information on this app.