Sound Meter (Noise & Decibel) add-on enables you to measure the surrounding sound (dB) and noise with your computer's microphone.
This add-on help you easily measure some important sound factors, such as the sound level in decibel, noise level, sound average and normalized sound value. When you open the app for the first time, it may ask you about the microphone access. Please accept the dialog box in order to start the add-on.
Also note that, the app may take few seconds before getting ready. So please be patient while the add-on is getting ready. Once the loader is disappeared, the add-on is ready to use. It uses the microphone in your system to capture the surrounding sound. If your computer done not have a microphone, please attach one to it before using the add-on. On top toolbar in the popup UI, you see several information about the surrounding sound.
If you see any bug, or have a feature request, please fill the bug report form in the addon's homepage (http://mybrowseraddon.com/sound-meter.html).