Audio Technology Fundamentals: From Physics to Device Implementation

This article provides a comprehensive introduction to audio technology fundamentals, covering both theoretical and practical aspects. It begins with an overview of audio effects and their evolution, discussing major brands like Dolby, DTS, and SRS, as well as proprietary solutions from manufacturers such as Huawei's Histen and Samsung's SoundAlive. The article then delves into the physical properties of sound, including sound pressure, sound intensity, and their relationships with distance and frequency.

The text explains key acoustic concepts such as amplitude, frequency, harmonics, and overtones, providing detailed explanations of even and odd harmonics and their effects on sound quality. It covers sound propagation phenomena including direct sound, early reflections, reverberation, diffraction, and scattering. The article also discusses important acoustic effects like the Haas effect, masking effect, and cocktail party effect.

The second major section focuses on electroacoustic devices, starting with the audio device industry chain and then examining speakers in detail. It covers different types of speakers (dynamic, balanced armature, piezoelectric, electrostatic), their classifications by frequency range and diaphragm shape, and their performance parameters including rated power, frequency response, impedance, harmonic distortion, sensitivity, and directivity. The article also discusses speaker modal analysis, acoustic short circuits, and sound chamber design.

Microphones are covered extensively, including capacitor microphones, dynamic microphones, and MEMS microphones. The article explains MEMS microphone advantages, working principles, and performance metrics such as signal-to-noise ratio, sensitivity, and frequency response. It also discusses multi-microphone applications including noise cancellation, backup systems, and beamforming.

The final sections cover power amplifiers (including smart PA technology), audio codec chips, and audio quality evaluation methods. The article provides both subjective and objective evaluation criteria, including frequency response curves, THD+N measurements, and various audio quality metrics.