English 
Chinese Introduction
In high-fidelity audio capture—whether in studio recording, acoustic testing, or smart device applications—nonlinear distortion in microphones is a persistent challenge. This issue is especially relevant in MEMS condenser microphones, which are widely used due to their compact size, cost efficiency, and ease of integration into digital systems.
In our ongoing commitment to improve microphone performance, SiSTC explores not only front-end transducer design but also post-processing techniques that enhance system-level audio quality. This article introduces a simple yet powerful method for reducing nonlinear distortion across the frequency and dynamic range of single-backplate condenser microphones.
Understanding the Problem: Nonlinear Distortion in Condenser Microphones
Condenser microphones—including most MEMS types—often suffer from second-order and intermodulation distortion under high amplitude or broadband conditions. These distortions manifest as:
- Unwanted harmonic content
- Reduced signal clarity
- Compromised measurement accuracy in lab-grade systems
- Perceptual degradation in voice recognition and recording applications
Traditional solutions involve hardware redesigns (e.g., dual-backplate configurations or diaphragm stiffening), which increase cost and complexity.
A Simple Post-Processing Solution
This study proposes a post-processing method that compensates for nonlinear distortion without modifying the microphone’s hardware. Key features include:
- ✅ Single-parameter compensation: Only one adjustable parameter is required, derived from microphone physical parameters or basic measurements.
- ✅ Wide compatibility: Easily implemented in analog front ends, DSPs, audio codecs, microcontrollers, or Application-Specific Integrated Circuits (ASICs) used in MEMS microphones.
- ✅ Fail-safe behavior: Overestimating the compensation parameter doesn’t introduce new distortion—at worst, the signal returns to its original state.
Experimental Results
📈 Harmonic Distortion Reduction
When tested with harmonic signals, the technique reduced second harmonics by ~40 dB, significantly improving total harmonic distortion (THD).
🎶 Two-Tone and Multitone Inputs
In complex signal environments, such as speech or music, the method reduced second-order intermodulation distortion by at least 20 dB, preserving signal integrity even at high SPLs.
Implementation Options
This method is highly flexible and can be integrated into various systems:
- Analog circuits (e.g., op-amp based signal chains)
- Microcontrollers with real-time audio processing
- Digital audio codecs or embedded DSPs
- ASICs embedded within MEMS microphones
- Software plug-ins in studio audio systems
🔍 At SiSTC, we support integration guidance and offer MEMS microphones designed with optimal SNR and linearity to complement such post-processing solutions.
👉 Explore our MEMS microphone lineup
Use Cases and Benefits
This technique is especially valuable for:
- 🎤 Smart speakers and mobile devices, where microphone performance is software-adjusted post-production
- 📊 Acoustic measurement systems, requiring high linearity for test integrity
- 🎧 Studio-grade audio interfaces, enhancing performance without physical redesign
- 🗣️ Voice AI applications, minimizing artifacts that degrade recognition accuracy
ConclusionIn a world where audio clarity and accuracy are more critical than ever, especially for edge AI, voice UX, and audio analytics, this simple distortion compensation technique provides an elegant solution. It empowers manufacturers and developers to improve microphone performance without altering hardware—driving down costs and shortening development time.
At SiSTC, we’re committed to supporting both the hardware and software side of audio innovation.
