This paper presents the results of a round robin test series of the SAE J1400 Sound Transmission Loss in which more than a dozen different acoustical laboratories participated. The round robin was sponsored by the SAE Acoustical Materials Committee, which is responsible for the SAE J1400 standard.
Based on the results of the round robin, significantly more definition, recommendations, clarifications and check procedures are being added to a new draft of the J1400 standard to assure improved reproducibility, repeatability and absolute measurement accuracy.
In addition, there are unique differences between current versions of the ISO 140, ASTM E90 and SAE J1400 sound transmission loss standards. These differences are discussed in this paper and a systemic advantage of the SAE procedure is highlighted.