So, you’re putting together an IoT system and thinking about adding some audio capabilities. Maybe you’re working on a smart home device or a voice assistant. Whatever the project, integrating sound can take that project to the next level. These days, audio features like voice commands, real-time communication, and high-quality playback aren’t just cool extras – they’re essential.

To make this happen, you’ll need an audio codec chip. Think of an audio codec chip as the translator for your device’s sound – turning analog signals (like your voice) into digital data that your tech can process and then back again into sound you can hear. Whether it’s for a doorbell camera that streams real-time audio to your phone or a smart speaker that plays your favorite songs, audio codecs are the unsung heroes making it all work.

Not sure where to start? Let’s break down what audio codecs do, why they’re important, and how to choose the right one for your project. Along the way, we’ll look at some of the most popular options on the market and how they’re used in IoT designs.

Key functions of Audio Codec Chips

Let’s talk about what makes audio codec chips so essential for your IoT design. At their core, these chips handle the heavy lifting when it comes to processing and managing audio signals. Think of it this way: when you speak into a microphone, that sound is in analog form. One of the chip’s main jobs is to perform analog-to-digital conversion (ADC), turning your voice into digital data that your device can actually work with. On the flip side, when it’s time to play back sound – like streaming music or a voice alert – the chip does the reverse through digital-to-analog conversion (DAC), translating digital audio data into sound you can hear through speakers or headphones.

But that’s not all. Audio codecs also handle compression and decompression, making sure the audio is packed efficiently for transmission and then unpacked seamlessly for playback. Without this step, sound quality would take a big hit – or worse, the data could become too bulky to transmit effectively.

These chips are often found in audio development boards, which are like playgrounds for developers working on sound-heavy IoT projects. Fortunately, many of these boards come preloaded with one or more codec chips, making it easier to test and prototype features like real-time playback, recording, noise cancellation, or even voice recognition. Whether you’re building a smart speaker or a voice-enabled gadget, these little chips are doing a lot of the behind-the-scenes work to make your device sound sharp and responsive.

Common Audio Codec Chips

There are plenty of audio codec chips out there, but here’s a closer look at a few popular ones and where they shine:

ES8311

If you’re working on a simple setup that doesn’t need stereo sound, the ES8311 might be your go-to. It’s a low-power mono codec chip that handles single-channel audio – perfect for tasks like voice recognition or basic audio output in embedded systems. With features like a low-noise pre-amp and headphone driver, it’s great for portable, battery-powered devices. However, if you need rich stereo sound, you’ll want to look elsewhere. You’ll often find this chip in ESP32-based boards like the ESP32-S3-Korvo-2 V3.0 and ESP32-LyraT-Mini.

ES8388

For stereo audio, the ES8388 steps it up. This chip supports both microphones and headphone amplifiers, offering two-channel ADCs and DACs for more immersive sound. It’s a favorite for smart speakers and multimedia devices, commonly found in boards like the ESP32-LyraT. While it’s slightly more power-hungry than the ES8311, it delivers better audio quality and versatility for advanced applications.

CX20721

Need premium sound? The CX20721 is built for high-end audio setups like smart speakers and AI-driven systems. It boasts dual ADCs and DACs with high sampling rates, noise reduction, echo cancellation, and beamforming (a technique that focuses sound capture or output in a specific direction, improving clarity and reducing background noise). In short, the CX20721 is designed to deliver crystal-clear audio for voice-controlled devices. This chip is more complex and consumes more power than simpler options, but for applications in which sound quality matters most, it’s worth it. You’ll find it on the ESP32-LyraTD-SYNA board.

ES8266

If voice-based applications are your focus, the ES8266 strikes a good balance between performance and efficiency. It handles stereo audio with two-channel ADCs and DACs and is optimized for voice input and output, making it ideal for devices like smart speakers. It doesn’t have all the bells and whistles of the CX20721 but offers solid performance at a lower cost and power consumption.

ESP32-DU1906

This one’s for the big leagues. The ESP32-DU1906 integrates an audio codec with a Bluetooth/Wi-Fi module, making it perfect for feature-packed smart speakers and AI systems. It’s loaded with advanced features like acoustic echo cancellation (AEC) and beamforming, ensuring clear audio even in wireless environments. While it’s powerful, it’s not the best choice for simpler setups due to its higher complexity and power consumption. You’ll often find it in the ESP32-Korvo-DU1906 board.

Building IoT Projects with Audio Codec Chips

Once you’ve picked the right audio codec chip, it’s time to bring your IoT project to life. This means connecting the chip to components like microphones, speakers, and the microcontroller – basically, the brain of your system. Development boards make this process a whole lot easier. Many come with pre-integrated codec chips, so you can hit the ground running with audio features like playback, recording, or even voice recognition.

Take the ESP32-LyraT board, for example. It features the ES8388 codec, which makes it perfect for creating smart speakers or voice assistants. With its stereo audio capabilities, you can design a system that captures and transmits clear sound in real-time – ideal for high-quality, interactive audio projects.

Once your hardware is set up, you’ll move on to programming the codec chip. Tools like the Arduino IDE or ESP-IDF provide libraries that let you configure your chip for specific tasks. Want your device to record audio and play it back? Or maybe compress and transmit sound wirelessly? The codec chip handles it all – converting analog sound to digital data, compressing it for transmission, and decompressing it on the other end for crystal-clear playback.

Final thoughts

Whether for basic applications like voice recognition or more complex systems requiring high-quality audio processing, there is a wide range of codec chips designed to meet different needs. The ES8311 offers an economical, low-power solution for mono audio processing, making it ideal for simple embedded systems. For more sophisticated audio applications, the ES8388 and ES8266 provide stereo sound capabilities, while the CX20721 and ESP32-DU1906 stand out for their high-end features such as noise reduction and echo cancellation.

As you can imagine, your choice of codec chip ultimately depends on the requirements of your application, and you need to balance such factors as power consumption, audio quality, and processing complexity. As IoT technology continues to evolve, the role of these chips will remain crucial in shaping the way devices communicate and interact with users.

Read our other resources

We’ve published a range of resources for our community, including:

• What is an audio codec in IoT?
• The best audio development boards
• Our guide to choosing a Wi-Fi module for your IoT project