Product Structural Design¶

Microphone Structural Design¶

Vibration Concept: In physics, vibration is broadly defined as any physical process that repeats periodically over time. Simply put, the back-and-forth motion of particles or objects is called “vibration,” which is a method of energy propagation.
Sound Generation: When one or more particles vibrate, they cause surrounding particles to vibrate as well. During this process (object vibration), energy waves are produced in the air (including infra-sound, sound waves, and ultrasound). Vibrational waves that can be detected by human hearing are called sound waves, with a frequency range of approximately 20-20,000 Hz.
Speech is the transmission of human language through sound waves. Language + sound waves = speech. Speech recognition involves decoding and recovering language from speech.

Choose analog microphones with a sensitivity of -32±3dB and signal-to-noise ratio >70dB. Refer to ☞Microphone Compatibility List for compatible models.
Select single-microphone or dual-microphone solutions based on functionality. Contact our technical team for specific recommendations.
Common microphone sizes are 7mm or 10mm rubber gaskets. Use 7mm for standard applications; opt for 10mm if vibration is present. Select interface type, cable length, and other specifications based on requirements.

Inlet Design: A sound inlet hole is mandatory. The diameter should correlate with the hole depth (housing thickness). See recommended specifications below:

Position the microphone hole on the front of the product, facing the user, to ensure optimal sound pickup and avoid obstruction by other components.
Consider waterproofing and dust-proofing for the microphone location if exposed to water or dust.
Keep away from water inlets, air vents, machinery, speakers, electromagnetic interference, and other noise sources. For best recognition performance, ensure ambient noise at the microphone remains below 60dB during operation.
Include mounting holes or slots that match the rubber gasket diameter (7mm or 10mm). Confirm exact dimensions with the microphone manufacturer, typically 0.1-0.2mm smaller than the microphone diameter.
Ensure convenient cable routing, away from high-voltage lines.
For dual-microphone setups, maintain a 4cm center-to-center distance. Consult our FAE for other spacing requirements.
For AEC (Acoustic Echo Cancellation) functionality, maximize distance between microphones and speakers. Keep speaker output below 95dB and microphone input below 83dB.
Consult our technical team before finalizing the structural design.
Avoid cavities between the sound inlet and microphone. Consider using a honeycomb pattern if needed.

Secure the microphone firmly to prevent movement, which could affect recognition.
Use RoHS-compliant RTV silicone (e.g., 703/704/737) or other organic materials.
Choose non-conductive silicone to prevent electrostatic discharge (ESD) from reaching the microphone pins. Contact the microphone manufacturer or our FAE for suitable adhesive types.
Insert the microphone fully into the mounting hole, ensuring proper alignment with the sound inlet.
Apply silicone with a thickness under 3mm. Allow 8-12 hours for full curing at room temperature. For thicker applications, apply in layers. Complete microphone installation early in production.
Avoid using hot glue for microphone fixation. Secure the wiring to prevent misalignment during handling.