In a standard Sound Transmission Loss (STL) test, a sample is placed between two test chambers. Based on the sound level reduction the material provides and various acoustical characteristics of the test chambers, the STL is determined. The opening in which the sample is mounted and sealed can vary in size and depth depending on the test method and chamber construction. Where the test sample is mounted within the fixture is up to the experimenter. Past research has indicated that when following the ASTM E90 test, placing the sample in the middle of the test tunnel yields a minimum STL value. An alternate test method (SAE J1400) is in common use for the measurement of smaller test samples, typically found in the transportation industry. This technique utilizes a sample of known sound transmission loss, such as a limp vinyl barrier, as a correlation sample to determine the STL. Receiving chamber microphones are also typically placed very close to the sample. As such, the influence of the test tunnel and the location of the sample can influence the resulting reported STL values. This paper presents measured and predicted STL values for different tunnel acoustical conditions and different sample positions.
|State||Published - 2015|
|Event||44th International Congress and Exposition on Noise Control Engineering, INTER-NOISE 2015 - San Francisco, United States|
Duration: Aug 9 2015 → Aug 12 2015
|Conference||44th International Congress and Exposition on Noise Control Engineering, INTER-NOISE 2015|
|Period||8/9/15 → 8/12/15|
ASJC Scopus subject areas
- Acoustics and Ultrasonics