Have you ever suffered from the noise of the neighbors?
SPL(sound pressure level) meter app uses your built-in microphone to measure noise volume in decibels(db), and shows a reference. I had calibrated a lot of android devices with an actual sound level meter (dBA).

REMEMBER!! Most smartphone microphones were aligned to human voice (300-3400Hz, 40-60dB). Voice calls do not require high-performance microphones.
Therefore the maximum value is LIMITED by manufacturers, and very loud sound(100+ dB) cannot be recognized. Moto G3 (max.80), Galaxy S6 (85dB), Nexus 5 (82dB), HTC Desire(82dB)...

See 6-7th images. I calibrated major android devices with an actual meter. You can trust the result in routine-noise levels (40-70dB). Please use it as an auxiliary tool.

* Main features:
- Upside down mode
- Level notification
- Material design

* Pro version added features:
- No ads
- Vibrometer
- Statistic menu (line chart)
- CSV file exporting
- Line-chart duration

* Do you want more tools?
download [Sound Meter Pro] and [Smart Tools] package.

For more information, watch YouTube and visit the blog. Thank you.