The output amplifier then converts the weak sound signal to a level suitable for display on the readout screen.

The input amplifier then converts that electrical charge into a voltage, which the electrical circuitry processes to produce a sound pressure level (SPL). The microphone turns fluctuating, sound-induced air pressure to a fluctuating electrical charge.

Sound level meters are composed of four main parts: a microphone, an input amplifier, an output amplifier, and a readout device. To ensure personnel safety, all readings taken by a sound level meter must be accurate and reliable.

Exposure to 100 dBA for over 14 minutesĪ sound level meter can measure sounds in decibels, but it must be calibrated regularly to ensure consistently accurate readings.

The following conditions increase the risk of hearing damage: Human hearing is more likely to be harmed as dBA increases, and it can happen faster at higher volumes. So the lowest note on a tuba (16 Hz) will have a lower dBA reading than its dB level.Įven minor dBA increases can have a significant influence on hearing health. Lower-frequency sounds, however, will have a lower output level because they are processed by the ear less efficiently. For example, the dB and dBA levels of a violin’s high-pitched E string are very similar. While dB represents unweighted sound pressure levels, dBA is A-weighted to better approximate human perception of the sound.įor high-frequency sounds, measurements for dBA are as high as those for dB. The decibel scale is logarithmic to better represent how our ears perceive changes in sound intensity.

Decibel scale who made it