Designed for developers building front-facing voice interfaces while retaining control over the host platform, the reSpeaker Flex XVF3800 Linear-4 combines directional voice capture, onboard XMOS audio processing and a modular split-board architecture. It is well suited for robots, kiosks, smart displays and interactive terminals where users speak primarily from the front. The linear array features four PDM MEMS microphones with 33 mm spacing and an approximately 180° front-facing pickup pattern that helps reduce sound pickup from behind. The microphone board connects to the XVF3800 core board through the included 20 cm, 24-pin FPC ribbon cable, allowing both boards to be positioned independently inside an enclosure. Powered by the XMOS XVF3800, the system provides AEC, AGC, DoA, multi-channel beamforming, VAD, noise suppression and dereverberation to support clearer far-field voice capture in noisy and echo-prone environments. In USB mode, the USB-C and locking PH2.0 ports support UAC 2.0 audio for use with PCs and SBCs. Developers can also use compatible I2S firmware with a XIAO ESP32S3 or another host MCU for embedded integration. USB and I2S operate as separate firmware modes. The core board includes an unpopulated XIAO ESP32S3 footprint, exposed I2S and I2C connections, a 3.5 mm AUX output and a connector for an external speaker. This is an open-board development platform; XIAO ESP32S3, enclosure and speaker are not included.
Front-Facing Voice Capture: Four PDM MEMS microphones in a linear array with 33 mm spacing deliver an approximately 180° forward pickup pattern with rear sound suppression. Well suited for kiosks, smart displays, robots, and interactive terminals.
XMOS XVF3800 Voice Processing: Onboard AEC, AGC, DoA, multi-channel beamforming, VAD, noise suppression, and dereverberation help capture clearer far-field speech in noisy, echo-prone environments.
USB UAC 2.0 Host Integration: In USB firmware mode, connect through USB-C or the locking PH2.0 interface for UAC 2.0 audio with compatible Windows, macOS, Linux, and SBC hosts. Supported systems use native USB Audio Class drivers, so no dedicated audio driver is required. USB-C provides board power, and USB firmware supports DFU.
Split-Board Design: Position the microphone array at the front or edge of an enclosure while placing the core board elsewhere. The included 20 cm, 24-pin FPC ribbon cable connects the two boards for flexible installation.
Open Host Integration: The XIAO ESP32S3 footprint is unpopulated, allowing developers to solder a XIAO module or connect an external MCU. I2S requires matching firmware and operates separately from USB. Exposed XVF3800 I/O, a 3.5 mm AUX output, and an amplified speaker connector support custom integration. XIAO ESP32S3, enclosure, and speaker are not included.