Anechoic chambers are mainly used for acoustic measurements, especially for low noise level measurements. It can provide an almost non-reflective acoustic environment so that the measurements made in it will not be affected by reflected sound, which helps to obtain more accurate acoustic data.
Regarding the noise range that an anechoic chamber can measure, the following aspects can be considered:
1. Frequency range
Anechoic chambers are usually designed to simulate free sound field conditions, which means that they can measure noise from very low frequencies to higher frequencies. However, the effective frequency range of an anechoic chamber is limited by several factors, including:
Cut-off frequency: This is the lowest frequency at which the anechoic chamber can provide free sound field conditions. Usually, the cut-off frequency of an anechoic chamber is related to the thickness and type of sound-absorbing material. Longer sound-absorbing wedges can provide lower cut-off frequencies.
Maximum test frequency: This depends on the design of the anechoic chamber and the capabilities of the measurement equipment.
2. Sound pressure level range
Noise floor: The noise floor level of an anechoic chamber is very low, and it is generally required that the noise floor is at least 6 dB lower than the sound pressure level of the sound source being measured, and preferably more than 12 dB lower. The background noise of the anechoic chamber can be determined by measuring the A-weighted sound pressure level and octave band sound pressure level at multiple points without a sound source.
 Measurement range: Anechoic chambers can measure noise from extremely low sound pressure levels to higher sound pressure levels, but specially designed equipment is usually required to measure extremely low sound pressure levels.
3. Measurement applications
 Product noise measurement: Anechoic chambers can be used to measure the noise of various products, from small electronic devices to large mechanical equipment, etc.
 Sound power level measurement: According to the national standard GB 6882-86, anechoic chambers can be used to measure the sound power level of noise sources.
 Other acoustic property measurements: Anechoic chambers can also be used to measure the sound absorption coefficient of acoustic materials, the frequency response characteristics of acoustic components, etc.
In summary, the range of noise that can be measured in an anechoic chamber is very wide, from low frequency to high frequency, from extremely low sound pressure levels to higher sound pressure levels. The specific frequency range and sound pressure level range depends on the design of the anechoic chamber and the purpose of the measurement.