[Updated: June 13] — Seeed’s v.2.0 version of its ReSpeaker Core mic array board advances to a Debian-driven, quad- A7 Rockchip RK3229 and offers a 6x mic array with a 16-meter wake-word range.



Seeed’s $99 ReSpeaker Core v2.0 is a major upgrade to its ReSpeaker far-field voice control SBC, replacing the MIPS-based Mediatek MT7688 SoC running OpenWrt Linux with an up to 1.5GHz, quad-core, Cortex-A7 Rockchip RK3229. The RK3229 is implemented via a new Seeed computer-on-module called the “Axol Core,” while the underlying baseboard provides I/O including HDMI 2.0 and a six-mic array, down from the 7-mic array on the original ReSpeaker. The board supports voice control features including smart speakers, voice assistants, voice conferencing, and talking robots.







ReSpeaker Core v2.0

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The updated ReSpeaker Core arrived only two weeks after Seeed’s $25 ReSpeaker Mic Array v2.0 , a 4-mic voice board without an onboard computer that’s designed to work with just about any desktop or embedded computer, including the original ReSpeaker. Since the ReSpeaker Core v.2 has its own computer and mic array, it does not work with the ReSpeaker Mic Array v2.0. Last year, Seeed introduced a ReSpeaker 4-Mic Array for Raspberry Pi add-on board, providing yet another option for ReSpeaker voice control applications.

The v2.0 model is touted for its 16-meter wake-word range, which is demonstrated in one of several videos. The spec sheet, however, says it has a 5-meter detect range, which suggests that this is required for voice interactions aside from the wake-up command. The ReSpeaker Mic Array v2.0 is limited to 3 meters.







ReSpeaker Core v2.0 rear view (left) and connected to laptop for setup

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The ReSpeaker has been redesigned with a larger (100 x 96 x 18mm) hexagonal shape and a small embedded Axol Core module. The original, and still available, ReSpeaker has round, 70mm diameter mic array and control boards that stack together. The v1.0 product enables you to buy the v1.0 control board and mic array board together or separately at $69 apiece. Seeed hints that in the future it may provide a more powerful module for the ReSpeaker Core v2.0 as an optional replacement for the Axol Core, offering somewhat similar modularity.

Seeed’s Axol Core module, which is named after the critically endangered axolotl (Mexican salamander), pairs the RK3229 with 1GB of DDR3 and a PMIC. According to a Seeed rep, the company will likely use the Axol Core in other projects, starting with ReSpeaker spinoffs, but has not announced plans to release it separately. This is the first RK3229 based module we’ve seen, although in January, Rockchip promised a Rockchip RK3229 SoM designed primarily for Android Things. It has yet to ship, and was not included in the Google’s Android Things 1.0 launch in early May, however.

The ReSpeaker Core v2.0 switches to a “software-based approach to voice enhancement” that runs algorithms on the RK3299 to process audio from the 6x microphones in real-time, says Seeed. The board supports open source noise suppression (NS) and keyword wakeup algorithms, as well as proprietary direction of arrival (DoA), beam-forming (BF), and Acoustic Echo Cancellation (AEC) algorithms from Alango, which Seeed describes as “a professional audio DSP company used in the automotive industry.”







ReSpeaker Core v2.0 detail view and legend

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Seeed has removed the earlier ATMega32U4 MCU, which controlled LEDs and sensors on the original board while also providing Arduino compatibility. You still get 12x programmable LEDs, but there are no more sensors or pushbuttons.

The v2.0 board is equipped with 4GB eMMC and a microSD slot, as well as an HDMI 2.0 port without audio output. This will support 4K video once the driver is available, but is currently limited to HD. There’s also a 3.5mm audio output jack and a JST 2.0 audio output connector.







ReSpeaker Core v2.0 and block diagram

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ReSpeaker Core v2.0 provides WiFi, Bluetooth BLE, and a 10/100 Ethernet port, as well as 2x USB 2.0 host and single micro-USB OTG and power-input device ports. A Grove expansion socket, GPIO, and a debug UART are also available.

The board ships with a Debian Linux stack posted on GitHub, and supports other Linux-based OSes in an “open software ecosystem.” The board is extensively documented, and the Seeed rep said the company will eventually release schematics. He also noted that Axol Core will be updated with Android 8.1 support by late July. The company provides hardware and software customization services for the mainboard.

Specifications listed for the ReSpeaker Core v2.0 include:

Processor (via Axol Core module) — Rockchip RK3229 (4x Cortex-A7 cores @ up to 1.5GHz); Mali-400 MP2 GPU

RAM (via Axol Core module) — 1GB DDR3

Storage — 4GB eMMC; microSD slot

Wireless — 802.11b/g/n and Bluetooth 4.0 BLE (via AP6212 module)

Networking — 10/100 Ethernet port

Media I/O: HDMI 2.0 port with HDCP 1.4/2.2, @ up to 4K/60Hz (when driver arrives) 6x mic array with 8-channel ADC 3.5mm audio jack JST 2.0 audio output connector

Other I/O: 2x USB 2.0 host ports Micro-USB 2.0 OTG port Micro-USB 2.0 device port for power input UART 8x GPIO Grove expansion socket (I2C and digital)

Other features — 12x RGB LEDs

Power — 5V micro-USB input; 200mA/5V standby, 330mA/5V algorithm mode consumption; PMIC (via Axol Core)

Weight — 50 g

Dimensions — 100 x 96 x 18mm

Operating system — Debian Linux; C++ SDK and Python wrapper







ReSpeaker Core v2.0 YouTube video



Further information

The ReSpeaker Core v2.0 is available now for $99 at Seeed’s ReSpeaker Core v2.0 shopping page. Extensive documentation is available on the wiki.

