So far, security camera microphone supplier - Sizheng has seen many users' reactions to product testing. In the process of user product selection, they always used different manufacturers' CCTV microphone to test and compare. In this processes, how to test is actually very important.
Sizheng has encountered such users. When they test the CCTV microphones compared to the CCTV microphones of different manufacturers, some are indoors and some are outdoors. Some are relatively close to air conditioning or noise sources, some are far away... So the test results are definitely different, and users use such results to judge the quality of the product, which is unfair to each manufacturer.
In the same environment, we must also consider that each microphone must be the same distance from the person, although not exactly the same distance, but at least the same. In addition, during the test, the sound effects of different distance should be tested, such as the sound effects at different distances like 1 meter, 2 meter, 3 meter, 4 meter... Of course, the process tester must be the same person, ensuring the frequency of the sound is consistent.
We must also consider accessing the device while ensuring that the environment and distance are same. Whether using IPC as a transmission or using a DVR as storage, we try to use the same machine or same model. For example, we have encountered same users using different IPCs as access device. As a result, the effect of playback from storage does have certain differences.
Although the same model of IPC may have difference, the IP camera has multiple audio input modes. Different decoding modes will produce different sound effects. Part of IPCs built-in has noise reduction capability, which can be reduced to some extent. The noise of audio monitoring (which also cause a part of the distortion). Turning to different functions will also produce different sound effects. Therefore, during the test, the audio decoding mode or the audio function of CCTV camera audio function will also lead to different effects.
This part is the most easily overlooked part. Many users think that there is no problem in the power supply for the cctv mic. It's no known that the CCTV microphone has certain requirements for power supply. Because different power supply (switching power supplies and linear power supplies) operate in different modes and it produce different ripple (current interference). Therefore, it is recommended that users use liner power supplies during testing. Although some CCTV microphones have add filters, the fact that the current is generated by the switching power supply is unavoidable. In addition, the amplification of the audio monitoring makes these currents more noticeable... So we recommend using a linear power supply if Conditions allow the use of the same power supply (centralized power supply) for testing...
This is extremely important in comparing the noise reduction performance in different CCTV microphones. In order to make the cctv mic sound more clearer(quiet), some manufacturers will reduce the magnification of the audio pickup. This will make the audio monitoring sound more quiet in some cases, but it also brings another question, that is, the reduction of the pickup distance or it is relatively difficult to make the sound farther away from the sound pickup. When testing the noise reduction effect of different manufacturers, it is recommended to adjust the magnification of different pickups (the adjustment buttons of some products of Sizheng audio pickup). Let the sound picked up by each pickup sound as big as it is, and then judge the noise reduction performance of different products...
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