Figure 5 is the test result of the sound absorption coefficient of multi-component sound-absorbing cotton materials of different models (200g/m2, 300g/m2, 400g/m2) under different test environments (temperature and humidity).

Fig. 5 Sound Absorption Coefficient Characteristic Curves in Different Test Environments

As can be seen from figure 5, from the results of the whole curve, the low-frequency to medium-frequency shows an increase trend, the change trend of the medium-frequency is relatively stable, and the change trend of the high-frequency shows a gentle trend. With the increase of test environment (temperature and humidity), the sound absorption coefficient of the low-medium frequency has no obvious change. In the high frequency band of 2000Hz, the curve shows a certain fluctuation and the value decreases. In the high frequency band, the curve results tend to be concentrated and the value is relatively stable.