1. Main Types of Microphone Elements
1.1 Dynamic Microphone
Working Principle: Dynamic microphones use a diaphragm attached to a coil, placed inside a magnetic field. When sound waves strike the diaphragm, the coil moves, generating an electrical current via electromagnetic induction (Faraday's Law).
Features: Durable and low-cost. Due to the presence of magnets and coils, it's bulkier, with limited high-frequency response. However, it delivers a warm and natural sound, ideal for capturing vocals.
Common Applications: Karaoke systems (KTV), live sound, PA systems.
1.2 Condenser Microphone
Working Principle: Condenser microphones use two plates (diaphragm and backplate) to form a capacitor. When the diaphragm vibrates due to sound waves, the capacitance changes, creating a corresponding electrical signal.
Features: High sensitivity and wide frequency response. Ideal for high-quality audio capture.
Common Applications: Studio recording, broadcasting, instrumentation.
1.3 Ribbon Microphone
Working Principle: A thin metal ribbon (usually aluminum) is suspended in a magnetic field. The ribbon moves with sound vibrations and induces an electrical signal.
Features: Smooth frequency response and natural sound but relatively fragile.
1.4 Carbon Microphone
Working Principle: Sound pressure changes the resistance of carbon granules, causing variations in current. These microphones were commonly used in early telephones.
Note: This type is now mostly obsolete.
2. Two Common Condenser Microphone Types: ECM vs MEMS
2.1 Electret Condenser Microphone (ECM)
Working Principle: ECMs use an electret material that holds a permanent electric charge, eliminating the need for an external bias voltage. However, an internal amplifier circuit still requires a power supply.
Advantages: Cost-effective, mature technology.
Disadvantages: Larger size, not suitable for SMT (Surface Mount Technology), signal attenuation risks, and variation in consistency during mass production.
2.2 MEMS Microphone
Working Principle: MEMS (Micro-Electro-Mechanical Systems) microphones are built on silicon wafers using semiconductor manufacturing processes. They often integrate an ASIC and sometimes a built-in analog-to-digital converter, providing digital output directly.
Advantages: Small size, SMT-compatible, highly stable and consistent performance.
Disadvantages: Higher cost compared to ECM.
Note: MEMS microphones with integrated amplifier or ADC are often referred to as pickup modules.
