With the acceptance of ASTM E3359-23, standard methods exist to use either the swept sine (impulse response) method or the broadband noise/interrupted source method to measure the decay time of a room. ASTM E3359-23 includes a provision for validating the impulse response measurement system against the long-used broadband noise/interrupted source method from ASTM E2235-04(2020). Once the impulse response can be captured and processed effectively, the resulting decay time can be used in the normalization of sound transmission measurements or absorption coefficient measurements. Both cases are presented here, demonstrating the validateddecay time and providing comparisons of the resulting transmission loss (TL) and Sound Transmission Class (STC ), normalized impact sound pressure levels (NISPL) and Impact Insulation Class (IIC), and absorption coefficient and Noise Reduction Coefficient (NRC) measurements.
Way et al. (Wed,) studied this question.