What Is the Response of a MEMS Microphone?

In audio engineering, the “response” of a microphone defines how accurately it converts sound into an electrical signal. For MEMS (Micro-Electro-Mechanical Systems) microphones, understanding their response characteristics—such as frequency response, sensitivity, dynamic range, and transient behavior—is essential to matching the right device to your application. This article breaks down each key parameter and shows how to evaluate MEMS microphone performance.

1. Frequency Response

Definition: The frequency response curve shows how output level varies with input sound frequency (typically 20 Hz to 20 kHz for consumer audio).

Flat Response: Ideal for accurate recording; the microphone reproduces all frequencies at equal levels.
Tailored Response: Some MEMS mics boost or attenuate bass or treble for voice enhancement or noise rejection.

When reviewing datasheets, look for a plot showing ±3 dB or ±1 dB deviation points—this indicates the usable bandwidth.

2. Sensitivity & Signal-to-Noise Ratio (SNR)

Sensitivity measures how much electrical output (in mV or dBV) you get per unit of sound pressure (dB SPL). Higher sensitivity reduces the required amplifier gain.
SNR (in dB) compares the microphone’s output level at a reference SPL (often 94 dB) to its own noise floor. A higher SNR means clearer capture in quiet environments.

Tip: A sensitivity of –38 dBV and an SNR > 60 dB are common targets for consumer devices like smartphones and wearables.

3. Dynamic Range & Acoustic Overload Point (AOP)

Dynamic Range = AOP – noise floor.
AOP is the maximum SPL a microphone can handle without distortion (e.g., 125 dB SPL).
Use Case: For loud settings (concert halls, machinery), choose a MEMS mic with AOP ≥ 130 dB and wide dynamic range.

4. Transient Response

Transient response describes how quickly the microphone’s diaphragm reacts to sudden sound changes (e.g., percussive hits). MEMS mics benefit from:

Low mass diaphragms for fast response.
Minimal ringing (overshoot) so notes sound natural.

Manufacturers sometimes provide impulse response plots or rise time specifications.

5. Choosing the Right MEMS Microphone

At Wuxi Silicon Source Technology Co., Ltd., our Digital MEMS Microphone Series is designed with optimized response profiles:

Broad, flat frequency response for true-to-life voice and instrument capture
High sensitivity & SNR (up to 64 dB) for low-noise recordings
AOP up to 130 dB SPL to handle loud environments without clipping
Fast transient response for accurate percussive and speech nuances

Whether you’re developing smart speakers, hearing aids, or industrial sensors, selecting a MEMS microphone with the right response characteristics ensures top-notch performance.