The miniDSP UMA-8 microphone array, with onboard direction detection, echo cancellation, and noise reduction, has a wide variety of applications. In this app note we'll run through its use with Cortana, the "intelligent virtual assistants" from Microsoft.

Why use the UMA-8?[Top]

By default, Microsoft Cortana uses the inbuilt microphone in your computer. This is fine if you are sitting at the computer, but for use of these programs as a "far field" hands-free assistant a more sophisticated microphone is needed. The UMA-8 has:

  • Beam-forming running across an array of 7 microphones to improve voice detection and eliminate extraneous noises.

  • Echo cancellation and noise reduction to reduce the effects of non-voice sounds (like music playing) and noise (traffic, kitchen noises etc).

The UMA-8 is "plug and play" – you do not have to configure anything to make it work with Cortana. If you wish, however, you can use the miniDSP plugin to tweak the processing parameters of the microphone array (recommended for advanced users only!)

 

Using the UMA-8 with Cortana[Top]

Plug the supplied USB cable into the micro-USB port on the UMA-8, and plug the other end into a spare USB port on your Windows 10 computer. Open the Control Panel and go to Manage Audio Devices. Select the Recording tab and set the miniDSP micArray as the default device:

Selecting the UMA-8 microphone array for Cortana

To enable Cortana to respond to hands-free voice commands ("Hey Cortana") on Windows 10, you will need to enable it. This is described in this article on c-net:

And that's it! You should now be able to say "Hey Cortana" from anywhere in the room to activate it. Check out Microsoft's help page for more details on how Cortana can help you.

cortana win10

Further experimentation[Top]

By default, the UMA-8 is configured for automatic direction detection. You can alter the behavior with the switches on the board as follows:

  • SW1: enable and disable microphone beam-forming.
  • SW3: manually select direction of beam-forming.
  • SW4: enable and disable automatic direction detection.

Note that the LEDs around the edge of the board (on the underside, if the switches are on the top) will indicate the direction of beam-forming.

After some experience with the setup, you may wish to tweak the audio processing parameters of the UMA-8. Start the miniDSP micArray configuration program and click the Connect button to change parameters. For example, to turn on the automatic gain control and increase mic signal levels, try settings like this:

miniDSP UMA-8 microphone array AGC settings

Wrapping up[Top]

That's it for this app note! Have fun, and please let us know about your UMA-8 and Cortana experience in our forum.


The miniDSP UMA-8 microphone array, with onboard direction detection, echo cancellation, and noise reduction, has a wide variety of applications. In this app note we'll run through its use with Siri, the "intelligent virtual assistant" from Apple loaded on OSx.

Note: this app note applies only to desktops and laptops running MacOS. The UMA-8 typically requires more power than can be supplied by phones and tablets.

Why use the UMA-8?[Top]

By default, Siri would use the inbuilt microphone in your computer. This is fine if you are sitting at the computer, but for use of these programs as a "far field" hands-free assistant a more sophisticated microphone is needed. The UMA-8 has:

  • Beam-forming running across an array of 7 microphones to improve voice detection and eliminate extraneous noises.

  • Echo cancellation and noise reduction to reduce the effects of non-voice sounds (like music playing) and noise (traffic, kitchen noises etc).

The UMA-8 is "plug and play" – you do not have to configure anything to make it work with Siri. If you wish, however, you can use the miniDSP plugin to tweak the processing parameters of the microphone array (recommended for advanced users only!)

Using the UMA-8 with Siri[Top]

Plug the supplied USB cable into the micro-USB port on the UMA-8, and plug the other end into a spare USB port on your Mac. Open System Preferences and then Sound, and select the miniDSP micArray as the input source:

Selecting the UMA-8 microphone array for Siri

To enable Siri to respond to hands-free voice commands ("Hey Siri") on the Mac, you will need to a. set up a keyboard shortcut and b. map the keyboard shortcut to a voice command. This is described in this article on MacWorld:

And that's it! You should now be able to say "Hey Siri" from anywhere in the room to activate it. Check out the section Apple's help page for more details on Siri.

macos sierra siri waveform

Further experimentation[Top]

By default, the UMA-8 is configured for automatic direction detection. You can alter the behavior with the switches on the board as follows:

  • SW1: enable and disable microphone beam-forming.
  • SW3: manually select direction of beam-forming.
  • SW4: enable and disable automatic direction detection.

Note that the LEDs around the edge of the board (on the underside, if the switches are on the top) will indicate the direction of beam-forming.

After some experience with the setup, you may wish to tweak the audio processing parameters of the UMA-8. Start the miniDSP micArray configuration program and click the Connect button to change parameters. For example, to turn on the automatic gain control and increase mic signal levels, try settings like this:

miniDSP UMA-8 microphone array AGC settings

Wrapping up[Top]

That's it for this app note! Have fun, and please let us know about your UMA-8 and Siri experience in our forum.


The miniDSP UMA-8 microphone array, with onboard direction detection, echo cancellation, and noise reduction, has a wide variety of applications. In this app note we'll run through its use with Amazon's Alexa "intelligent personal assistant" and a Raspberry Pi.

This app note is based heavily on the article published by Amazon for their Alexa sample application.

Why use the UMA-8?[Top]

In the Amazon example article for the Raspberry Pi, it's suggested that a cheap USB microphone be used. (The Raspberry Pi does not have an inbuilt microphone.) This is not an optimum solution. Instead:

  • The UMA-8 has beam-forming running across the 7 microphones, which improves voice detection.

  • The UMA-8 also has echo cancellation and noise reduction, to reduce the effects of non-voice sounds (like music playing) and noise (traffic, kitchen noises etc).

The UMA-8 is "plug and play" – you do not have to configure anything to make it work with the Raspberry Pi and Alexa, just plug it into your Pi and follow the instructions!

1. Getting connected[Top]

Connect your Raspberry Pi to a keyboard, mouse, and an HDMI monitor or TV. For the UMA-8, just plug it into one of the USB ports. (It is powered over USB).

When installing the Alexa application, you will have a choice on whether to output audio from the 3.5mm analog jack or over HDMI. We selected HDMI and connected the Pi directly to the second input of a nanoAVR HD so the audio output from the Pi goes through a home theater system with room EQ. We bet Alexa never sounded so good :)

Photograph of UMA-8, Raspberry Pi, and nanoAVR HDA

Before powering on the Pi, download Raspbian from the Raspberry Pi Foundation and burn it to a micro-SD card. Plug the micro-SD card into the Pi and plug in the power. You will see your monitor or TV come up with the Raspbian desktop.

At this point, you may like to explore a little. If you are using a Raspberry Pi 3 with inbuilt Wifi, use the Settings (top right of screen) to join your wireless network. You may also want to change your keyboard layout to U.S., as it defaults to a U.K. layout.

2. Setting Up[Top]

All of the steps are documented in the Amazon article. You will need to create an Amazon developer account and "register" your Raspberry Pi. Then, using the terminal in Raspbian, download and install the sample application.

You will need to edit a text file to enter the credentials Amazon generated for your Pi. When you do so, be aware that for the field "Product ID" you must use the value that Amazon labels "Device Type ID." (If you use "Security Profile ID", it won't work and you will have to start again.)

With the credentials entered, run the installer. Select Yes to the prompts asking if you want to download required software. You will also need to select audio output from the 3.5mm jack or HDMI. (We used HDMI.) The installer may take half an hour or more to run.

amazon dev account

3. Running[Top]

To start the Alexa client, follow the steps in the Amazon article. Be sure to follow all steps in the instructions exactly!

You will need to open three terminal windows and execute a command in each of them. After entering the second command, wait until a window pops up asking you to authenticate. Clicking the Yes button will open a browser window – you will need to log into your Amazon developer account and then click "Okay."

The third command starts the "wake word" service, so you can say "Alexa" to wake up the device. You don't have to use this. Instead, you can just click the "Listen" button on the screen.

Once you have completed all steps, just say "Alexa". You should get a beep in response, after which you can ask it any question you like.

By default, the UMA-8 is configured for automatic direction detection. You can alter the behavior with the switches on the board as follows:

  • SW1: enables and disables microphone beam-forming.
  • SW3: manually select direction of beam-forming (if beam-forming is turned on and automatic detection is turned off).
  • SW4: enables and disables automatic detection of microphone direction.

(The LEDs around the edge of the board will indicate the direction of beam-forming.)

After some experience with the setup, you may wish to tweak the audio processing parameters of the UMA-8. To do this, you will need to unplug it from your Raspberry Pi and plug it into your Windows or Mac computer. Start the miniDSP micArray configuration program and click the Connect button to change parameters. For example, to turn on the automatic gain control and increase mic signal levels, try settings like this:

miniDSP UMA-8 microphone array AGC settings

To do more, use the Alexa app on your iOS or Android device to browse for and add "skills."

Limitations[Top]

There are some things to be aware of:

  • If you are outside the USA:

    • You will have difficulty getting the companion Alexa app, as it's only available in the US Apple App Store and Google Play Store. There are workarounds, at least for the iOS version, like here.

    • You will not be able to set your location to outside of the USA.

  • Some things are not supported with this sample/Raspberry Pi version, like Amazon Music. You can still add skills with the Alexa app.

Wrapping up[Top]

That's it for this app note! Have fun, and please let us know about your UMA-8 and Raspberry Pi/Alexa experience in our forum.