Sound chip

A sound chip is an integrated circuit designed to produce audio signals through digital, analog or mixed-mode electronics. Sound chips are typically fabricated on metal–oxide–semiconductor mixed-signal chips that process audio signals. They normally contain audio components such as oscillators, envelope controllers, samplers, filters, amplifiers, and envelope generators.

History

A number of sound synthesis methods for electronically producing sound were devised during the late 20th century. These include programmable sound generators, wavetable synthesis, and frequency modulation synthesis. Such sound chips were widely used in arcade game system boards, video game consoles, home computers and digital synthesizers.
Since the late-1990s, pulse-code modulation sampling has been the standard for many sound chips, as used in the Intel High Definition Audio standard of 2004. The PCM sampling method is used in many mobile phones and sound cards for personal computers. This widespread use is part of the digital sound revolution that started in the 1980s.

Types

There are multiple types of sound chips, which are divided based on their use.

While traditional sound chips focus on general audio synthesis, voice chips represent a specialized category optimized for voice-related applications. Based on market trends, they can be divided into five primary types, each with distinct technical characteristics and use cases.

Type	Core features
One-time programmable voice chips	OTP, short playback duration, low audio quality, non-rewritable Extremely low cost but high minimum order quantity Example: Vehicle reversing alerts, simple toy prompts
Flash voice chips	Built-in/external Flash storage, support WAV encoding Require dedicated tools for voice burning, cumbersome operation Moderate audio quality, no significant cost-performance advantage
MP3 voice chips	Dominant market solution with integrated MP3 decoding Include dedicated audio DSP, MCU, and external storage Representative models: KT404A series, KT142C series Advantages: USB voice updates, flexible volume control, combined playback Disadvantage: Higher power consumption
Text-to-speech voice chips	High technical barrier, limited suppliers Support TTS via Universal Asynchronous Receiver/Transmitter（UART） interface Drawbacks: Robotic voice quality, extremely high cos
Voice dialog chips	Support local/cloud-based voice recognition Local recognition: Low-end toys Cloud recognition: Require Wi-Fi/mobile connectivity, higher latency High-end solutions are costly

Applications

Sound chips are commonly used in various digital electronic devices, particularly personal computers, video game systems, electronic musical instruments, and digital telecommunications.