What are the methods used for sound level meter calibration?

Answer 1

Sound level meter calibration is a critical aspect of maintaining the accuracy and reliability of acoustic measurements. Two primary methods are commonly used for sound level meter calibration, both of which play a crucial role in ensuring precise acoustic measurements:

Acoustic Calibration: Acoustic calibration involves the use of a calibrated sound source, often referred to as a "calibrator" or "pistonphone." This method is based on generating a known and stable acoustic signal with a precisely controlled sound level. The sound source emits a pure tone at a specific frequency and sound pressure level, which the sound level meter then measures. By comparing the meter's reading to the known source level, adjustments can be made to the meter's settings, ensuring its accuracy in measuring acoustic signals. Acoustic calibration is particularly effective for ensuring that the microphone and associated electronics of the sound level meter are functioning correctly and that the meter responds accurately to sound pressure levels.

Electrical Calibration: Electrical calibration, also known as "electroacoustic calibration," relies on electrical signals to simulate acoustic measurements. This method generates electrical signals that correspond to specific sound pressure levels and frequencies. These signals are then input into the sound level meter's microphone or input port. The meter measures these electrical signals and displays them as equivalent acoustic levels. Electrical calibration is valuable for assessing the entire measurement chain, including the microphone, preamplifier, and signal processing electronics of the sound level meter. It ensures that the entire system accurately transforms acoustic signals into electrical measurements.

The choice between these two calibration methods often depends on the specific requirements of the measurement task and the availability of appropriate calibration equipment.