SAE Standards Works
Acoustical Materials Committee
J2883 - Laboratory Measurement of Random Incidence Sound Absorption Tests Using a Small Reverberation Room
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Laboratory Measurement of Random Incidence Sound Absorption Tests Using a Small Reverberation Room
This SAE Recommended Practice describes a laboratory test procedure for measuring the random incidence sound absorption coefficient of a material in a small size reverberant sound field by measuring decay rates. Materials for absorption treatments may include homogeneous materials, nonhomogeneous materials, or a combination of homogeneous, nonhomogeneous, and/or inelastic impervious materials. These materials are commonly installed in transportation systems such as ground vehicles, marine products, and aircraft to reduce reverberant sound build-up and thus reduce the noise level in the environment by minimizing reflections off of hard surfaces. The test method described herein was developed also to describe a way to measure the absorption performance of a part or a sound package system that will relate to an application. to rank order materials for application on panels using general automotive steel but also may be applicable to other situations or conditions. The absorption performance for most materials and systems varies as a function of frequency. Accordingly, this test procedure includes provisions for measuring absorption over a frequency range found applicable to many transportation systems. Samples that are used typically in transportation industry are not thick enough to provide any significant absorptive properties below 250 Hz. Combining the size of the sample and the frequency range of interest for automotive and related applications, this test method has been developed for conducting measurements using a small reverberation room where the frequency range of interest would be from approximately 250 to 8000 Hz 1/3rd octave band frequency.