GB/Z 27764-2011 Translated English of Chinese Standard (GB/Z 27764-2011, GBZ27764-2011): Acoustics -- Determination of sound transmission loss in impedance tubes -- Transfer matrix method [Buy--download True-PDF in 3-second: https://play.google.com/books > Sign in > This BOOK > "3-dots" > Export > Save as "*.pdf"]

This guiding technical document stipulates the measurement of normal incidence sound insulation (or normal incidence sound transmission loss) of acoustic materials or acoustic structures, in impedance tubes, by using the transfer matrix method. This guiding technical document is applicable to the measurement of the normal incidence sound insulation of locally reactive acoustic materials, such as sponges, cotton felts, soft thin plates, whose test frequency is in the quality control area (that is, there is no sound propagation parallel to the material inside the material). It is applicable to the comparison of sound insulation performance of acoustic materials, in the development stage. Since the sound transmission loss of a material is closely related to its physical properties (such as elastic modulus, density, structure factor, etc.), the measurement methods specified in this guiding technical document can be applied to relevant basic research and product development. This guiding technical document is not applicable to the identification test of the sound insulation performance of the product. This guiding technical document uses an impedance tube, one or more microphones, and a digital acquisition & analysis system.