The maximum fast sound pressure level LpFmax is used to measure sound generated by elastomeric ball drop, following ISO 10140-5 and ISO 16283-2. The LpFmax is the maximum of the fast sound pressure level LpF over time and is being considered by the ASTM E33 technical committee for measuring sound generated by heavy/hard ball drop. Some sound level meters use time constants that are longer than the standard time constant for LpF in low-frequency fractional octave bands, for the purpose of maintaining adequate time-bandwidth product and measurement repeatability for statistically stationary sounds. In this paper, the effect of these longer time constantsis investigated for ball drop LpFmax. Waveforms of ball drop sounds are processed using these longer and the standard 0.125 second time constants for ball drops onto several floor–ceiling systems. The effects on acoustic performance comparisons across floor–ceiling systems are noted.
Charles Oppenheimer (Wed,) studied this question.