The decibel meter - sound level meter is a metrological instrument used to measure the intensity of sound in a space by measuring the sound pressure in decibel units (dB), which is the unit of measurement of sound intensity.
The more advanced devices may also provide other functions, such as sound recording, data storage, and frequency analysis.
Decibel meters are important for hearing protection, as they can help control exposure to high noise levels that can cause ear damage. They are also used to assess sound performance in recordings, sound systems, concerts, and other musical applications.

Decibel meters are divided into different categories based on technical specifications and their compliance with international standards. The most commonly used classification system is provided by the International Electrotechnical Commission (IEC).

1. Class 2: These sound level meters are commonly used in industrial, commercial, and general-purpose applications. Class 2 sound level meters provide good accuracy and are suitable for noise measurements in professional environments, community noise assessments, and basic environmental noise monitoring.
2. Class 1: Class 1 decibel meters are used in a wide range of professional applications, including environmental noise assessments, industrial hygiene, occupational health, and building acoustics. They offer high accuracy and comply with the strict tolerances set by standards.