Characteristics of Electret Microphones After Integration into Devices

Performance Variations

After integration, the microphone's sensitivity typically decreases, but resonance at certain frequencies can lead to increased sensitivity at those points. The frequency response changes are more complex and can be categorized into three cases:

1. The microphone already has an optimal frequency response, requiring no adjustments. In this case, the device casing should be designed to maintain the original response without interference.
2. The microphone does not meet the required frequency response. Here, the casing, position, and cavity shape must be carefully designed to optimize the overall response.
3. Although the microphone has an optimal frequency response, external factors (such as casing design) affect the device's overall response significantly. A customized microphone tailored to the specific casing design may be required.

Omnidirectional Microphones

Omnidirectional microphones are commonly used in communication devices. While their installation position and sound inlet design are less demanding, avoiding sound resonance in the cavity is crucial to maintain a flat frequency response curve. Additionally, the distance between the front cavity inlet and the diaphragm should not be too large to prevent time delays between direct and reflected sounds, which can cause sound interference and resonance.

Directional Microphones

When integrating directional microphones, particular attention must be paid to the rear sound inlet. The rear and front inlets should ideally receive sound from the same source to preserve directional characteristics. The placement, size, shape, and number of sound inlets significantly impact the microphone's performance. These parameters should be fine-tuned through experimentation, as sound characteristics in real environments are complex and difficult to resolve through simple calculations.