Determining Sound Transmission Loss of SAE J1400 Control Sample 2019-01-1579

SAE acoustics materials committee published updates of SAE J1400 standard - Laboratory Measurement of the Airborne Sound Barrier Performance of Flat Materials and Assemblies in 2017. In the standard the control sample is defined with a specific construction to determine the validity of the test suite. A set of measured sound transmission loss data are included in the published updated standard. Autoneum North America Acoustics lab constructed a control sample based on the design in the standard. Measurement on sound transmission loss of this control sample was performed and compared with published data as well as simulation based on transfer matrix method and finite element method. The sound transmission loss data measured by J1400 standard are largely depend on the sample size, room size, sample sealing, niche effect, etc. of the test suite. This paper is an attempt to investigate the “true” value of sound transmission loss for this control sample and discuss what improvements need to made in the STL test suite in order to have a good measurement of sound transmission loss.