The minimum noise level for the testing environment of a soundproof speaker depends on the specific application and testing requirements. According to the search results, the following is some relevant information:
 
1. Noise level of the soundproof speaker:
-The internal noise level of a soundproof speaker usually needs to be below 40dB to ensure the accuracy of the test.
-In some more precise tests, the noise level of the soundproof speaker may need to be lower, even reaching between 10-20 decibels.
 
2. Noise level of the anechoic chamber:
-The noise level in the anechoic chamber is usually between 10-20 decibels, and for more precise testing, it may be necessary to reach below 10 decibels.
 
3. Test the noise level of the soundproof box:
-The noise level of the test soundproof box can be absorbed and processed by acoustic materials to produce a low-noise and high quietness acoustic free field space within the range environment.
 
In summary, the minimum noise level required for the testing environment of a soundproof speaker is usually below 40dB, but in more precise testing, it may need to reach between 10-20 decibels or even lower. The specific noise level requirements should be determined based on the test object and testing standards.