Different frequency will have different noise coefficient

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 There will be a different frequency sound absorption coefficient. People use the sound absorption coefficient frequency characteristic curve describing the sound absorption performance at different frequencies of sound insulation materials. In accordance with the ISO standard and the national standard, the frequency range of sound absorption coefficient in the test report is 100-5KHz.
The numerical absorption coefficient 100-5KHz are averaged to get the average sound absorption coefficient, the average absorption coefficient reflects the overall performance of sound-absorbing sound-absorbing material. Acoustic performance in engineering commonly used noise coefficient NRC rough evaluation in language frequency range, which is a numerical arithmetic insulation materials in the absorption coefficient 250, 500, 1K, four 2K frequency on average, four to five homes in rounding to 0.05. Is generally believed that the sound-absorbing material NRC is less than 0.2 is reflecting material, NRC is greater than 0.2 of the sound-absorbing material is considered sound-absorbing material.
When the need to absorb a large amount of energy to reduce indoor noise and reverberation, often need to use the high sound absorption coefficient of the absorbing material. Such as polyester fiber sound-absorbing cotton (cotton insulation, sound-absorbing sponge) Pyramid, wave absorbing sponge, centrifugal glass wool, rock wool etc. belong to the high NRC absorption material, polyester fiber sound-absorbing cotton 5cm thick 35kg/m3 (insulation cotton) NRC can reach 0.95.






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Tags: noise coefficient