The Seeed reSpeaker Flex XVF3800 - Circular with XIAO ESP32S3 4-Mic Array is designed for robots, smart signage, and other embodied AI applications that need reliable voice capture at a distance. Built around the XMOS XVF3800, it combines four microphones with advanced audio processing to help systems hear voices clearly, even in noisy environments.

On-board AI acoustic algorithms, including Acoustic Echo Cancellation (AEC), beamforming, and noise suppression, work together to reduce background noise, minimise echoes, and focus on the speaker's voice.

The array features a flexible split-board design and is available in two configurations: Linear and Circular. This product is the Circular version. If you require the Linear version, you can find it here. Its adaptable design makes it easy to integrate into different products and enclosures, while support for both USB and I2S modes ensures compatibility with a wide range of hardware platforms.

Whether you're building a voice-enabled robot, interactive display, or another embodied AI system, the 4-Mic Array provides clear far-field voice capture in a compact and adaptable design.

Features

• Innovative Modular Split Design

  • Separates the core processing board from the microphone array board via a flexible FPC cable, enabling easy integration in space-constrained robotics and embedded applications. For use cases such as desktop or humanoid robots, the mic array board can be positioned near the sound source, while the core board can be placed elsewhere inside the device. This design helps minimize interference from internal motor and servo noise, resulting in improved voice capture performance.

• Flexible Array Configurations

  • Available in two standard configurations: 4-mic circular array for 360° spatial pickup, and 4-mic linear array for 180° directional pickup.
  • In robotics applications - the circular array can be mounted on the robot’s head for omnidirectional voice capture.
  • For smart digital signage - the linear array is well-suited for front-facing placement, optimizing voice pickup for typical user interactions directly in front of the display.

• XMOS XVF3800 for Advanced AI Audio Processing

  • On-board AI acoustic algorithms for better sound quality. Features AEC, multi-beamforming, de-reverberation, DoA, dynamic noise suppression, AGC, delivering stable and reliable voice capture performance.
  • AEC (Acoustic Echo Cancellation) - AEC removes acoustic echo caused when sound played from the system is picked up again by the microphone array. AEC is critical in full-duplex communication systems such as conferencing devices, voice assistants, and interactive systems.
  • NS (Noise Suppression) - NS reduces unwanted background noise from captured audio. By identifying and attenuating non-speech components, such as fan noise, motor and servo noise, ambient chatter, keyboard typing, or environmental hum, NS enhances the SNR (signal-to-noise ratio) in real time. NS is essential in voice interactive systems including smart home and industrial voice control, voice assistants, educational devices, smart interactive terminals, and robots.

• Powerful Far-Field Voice Capture

  • With far-field voice capture up to 5 meters and the circular 4-microphone array (100005504, 100070894) supporting precise Direction of Arrival (DoA) detection, the reSpeaker Flex delivers reliable voice capture and accurate sound source localization for interactive and voice-driven applications.
  • Far-field Voice Capture Up to 5m - This enables clear command recognition in larger spaces without requiring users to stand close to the device, making the reSpeaker Flex ideal for voice interactive setups like smart digital signage.
  • Circular 4-Microphone Array Supports 360° DoA The circular 4-mic array enables accurate 360° DoA detection, allowing the reSpeaker Flex to identify where a voice is coming from. This spatial awareness enhances interaction performance, supports speaker tracking, provides a strong foundation for advanced beamforming, and allows users to interact with the robot from anywhere around it.

• Compact Design for Embedded Applications

  • Bottom-Firing Microphones - The acoustic ports are positioned on the back side of the mic array board, reducing interference from front-facing components. This design also allows the microphones to be placed closer to the sound source or device surface, maximizing voice pickup performance.
  • Compact Size, Powerful Performance - With just 44 mm mic spacing and a diameter of 73 mm for the circular array, and 33 mm spacing with a length of 110 mm for the linear array, the design fits easily into space-constrained embedded applications. Despite its compact size, it delivers outstanding voice capture performance, achieved through the combination of optimized hardware design and acoustic tuning.

• Developer-Friendly Integration

  • The reSpeaker Flex with no XIAO versions (100005504, 100099135) come with factory-installed USB firmware.
  • The reSpeaker Flex with XIAO ESP32S3 versions (100070894, 100026178) come with factory-installed I2S firmware.
  • Plug-and-Play via USB: A standard USB interface enables quick connection to devices such as Raspberry Pi, NVIDIA Jetson, and PCs running Windows, Linux, or macOS, no drivers or complex setup required.
  • I2S for MCU Integration: Direct I2S support allows seamless integration with MCU platforms like the XIAO Series and Arduino, making it easy to build embedded voice-enabled applications with minimal hardware overhead.
  • XIAO ESP32S3 Pre-Soldered Options: Two variants (100070894, 100026178) come with a pre-soldered XIAO ESP32S3, enabling native support for ecosystems such as ESPHome and Home Assistant. This allows developers to easily extend applications into smart home scenarios and beyond.

• Fast, Scalable, and Customizable for Production

  • Seeed Studio offers customization services include hardware modifications such as adjusting the size or shape of the microphone array board to better fit space-constrained robotics and embedded voice interaction scenarios. Algorithm tuning is also available to further optimize audio performance. For reference, similar approaches have been applied in open-source projects like the Reachy Mini desktop robot.

Specifications

Feature	Description
Core Chip	XMOS XVF3800
Amplifier	Texas Instruments TPA3139D2, Supports 10W Speakers
Audio Algorithms	AEC, AGC, DoA, Beamforming, VAD, Noise Suppression, De-reverberation
USB Interfaces	1x USB Type-C, For external connection and debugging; 1x USB JST Connector, For internal routing and motherboard integration;
Other Interfaces	1x XIAO Compatible Pads; 1x XMOS XVF3800 XTAG Debug Pads; 1x XMOS XVF3800 io Pads;
Audio Outputs	1x 3.5mm Audio Jack; 1x 2-Pin Speaker Connector;
Power Supply	5V Input: Via USB Type-C or 5V JST Connector; 12V Input: Via 2-Pin Terminal 12V Connector;
Mic Array Interface	1x 24-Pin FPC Connector
Button	1x Reset Button; 1x Boot Button;
Maximum Sampling Rate	16kHz

Mic Array Board

Microphone	4x High-performance PDM MEMS microphones
Array Topology	44 mm spacing arranged Circular Mic Array
Pickup Pattern	360° omnidirectional audio capture
Pickup Range	Up to 5 meters
Interface	1x 24-Pin FPC connector
Mounting	3 × M3 mounting holes

Resources

• Hardware overview image 1
• Hardware overview image 2
• Hardware overview image 3
• reSpeaker Flex Flyer - EN
• XMOS XVF3800 v3.2.1
• reSpeaker Series Flyer - EN
• reSpeaker Flex XVF3800 Circular.step
• reSpeaker Flex XVF3800 Core Board.step

Package Contents

• 1x reSpeaker Flex Core Board
• 1x reSpeaker Flex Circular Mic Array Board
• 1x 20cm FPC Cable
• 1x Pin Connectors