Comparison of two methods of noise dosimeter calibration using a portable calibration medium

The calibration of noise dosimeter based on a percentage of noise dose exposure has been conducted in Laboratory of Acoustics and Vibration, Sub-directorate of National Measurement Standards for Acoustics and Vibration, National Standardization Agency of Indonesia (SNSU-BSN). The aim of this work is, therefore, to realize calibration of noise dosimeter of the aforementioned parameter using two methods at the frequencies of 125 Hz, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, and 8000 Hz. The first method is carried out by comparing the measurand between the reference and DUT (device under test) by a substitution technique. Meanwhile, for the second method, the main parameter indicated by the two instruments will be compared directly. The determined parameter is a percentage of noise dose exposure that can be calculated from sound pressure levels (SPL) of 104 dB, and 114 dB respectively at the specific duration time. In the first method, the maximum deviation was found at the frequency of 4000 Hz and 8000 Hz that whose value is 2.3 % for the horizontal position, and 2.2 % belongs to the vertical position. Meanwhile, for the second method, the maximum deviation of percentage dose is obtained about 4.3 % and 4.1 % for the two positions respectively. In addition, these methods are necessary to be validated using the absolute method that was recently under research.