A decibel (dB) meter is a device that records and measures the intensity of soundwaves. While dB meters are typically handheld or standalone devices, you can use your computer as a dB meter using dB meter freeware, such as the Digital Level Meter, Waveseeker, or Decibel Meter programs. These programs will enable you to treat your computer as a fully-functional dB meter in no time.
Navigate to the webpage of the dB meter of your choice and click on the "Download" link.
Save the download to your desktop for safe keeping.
Double click on the installation file to install the program.
Restart your computer.
Connect a microphone to your computer and open the program to begin recording and analysing soundwaves in your vicinity.