The Cirrus Logic Voice Capture Dev Kit (598-2471-KIT-ND) is a complete solution for developing a hands-free product enabled with the Amazon Alexa Voice Service (AVS). The kit features Cirrus Logic’s SoundClear® voice capture solution, smart codec, MEMS microphones and control console that leverages the AVS APIs to help developers easily build commercial-grade, voice-activated products. This solution reduces development costs and accelerates the integration process to enable innovation.

The kit contains:

The voice capture board can be attached to the Raspberry Pi 3 either by cable, which is included, or placed as a hat on top of the Raspberry Pi 3.

Out of Box


Un-assembled Kit
Assembled Raspberry PI 3, Duet Board & Speaker in hat configuration.

Amazon Voice Services Integration

Open your web browser and connect to https://raspberrypi:3000/ your web-browser will warn about an insecure connection, just proceed with the invalid security certificate:

Amazon Voice Services (AVS) Configuration

Next open Sign-On to Amazon:

Sign In to
Select Alexa Tab
Select the Get Started option for Alexa Voice Service







Tuning on the Duet board is streamlined and quite easy.  The board will sound great already out of the box, so the tuning is really only necessary for getting it to sound best with your specific application or if you change the mics or speaker.

The first part you can configure is the TX bypass gain

for SoundClear.  You can also enable or disable SoundClear.


The next setting is if you change mics from those built in.

Here you just have to specify that you are using external mics

and what the spacing is between them.

Here you can configure the RX paths gain and equalizer.

This is for changing the sound of the speaker.

Here you are messing with your basic input gains.  This is for

making sure you are picking up enough sound through the mics.

This last section is for the noise cancellation.  You can adjust

the noise cancellation delays at the mic or the reference.  You

can also change the DTD threshold necessary to pic up the mic

for noise cancellation.



The first graph output is the Audio levels.

It has two graphs, one showing the input gain and the other

showing the output gain. 

The second graph is the Audio Mode.  This will show when the TX, RX,

or both paths are in use.

The ERLE shows the noise cancellation between the mics.  This you will look

at while making changes to the noise cancellation parameters.

This shows the DTD.  This is the threshold for the necessary for the TX to

be over for the mics pick up commands over the RX path.

This is the RX EQ.  This is used for if you are making changes to the

RX equalizer.




This is a very streamlined and user friendly setup for tuning your audio.  It focuses on the necessary parameters and ones that may need to be changed for any application.  For a more in-depth look at the tuning you can check out the tuning guide below.




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