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Guenter Villnow
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Guenter Villnow
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In this day and age of  Covid -19 social distancing where public events are cancelled, quite few of us are looking for ways to create immersive content. One way to do so is using a binaural immersive audio experience over headphones. This app note demonstrates the use of ambiMIK-1, a USB microphone featuring four low-noise microphone capsules and integrated preamps, as the perfect fit for an all in one solution for your next livestream concert or 3D audio recording . With the help of Dirac Research's binaural plugin, we will demonstrate how one can setup a powerful system with only few clicks and minimal investment.  For this scenario we'll be using the powerful open source Open Broadcaster Software (OBS) to record and process audio + video.

Please note that OBS is third-party software. miniDSP is not able to directly provide support for this software. For questions or issues specifically related to OBS, please refer to the OBS Forum and its online tutorials.

1. Software installation before you proceed [Top]

Let's list the software you'll need to download and install before you proceed

- Download and install all ambiMIK-1 drivers and Dirac Live Binaural plugin as per the ambiMIK-1 user manual

- Download and install OBS build for your OS. 

- Download and install the OBS ASIO plugin. This plugin will be used to discover the ambiMIK-1 multichannel interface inside your OS. Note that v3 version is based from a 3rd party library that needs to be installed separately (You need to download bassasio.dll from https://www.un4seen.com/bassasio.html.). You can find detailed instructions on the OBS ASIO plugin from here.

- Download and install the VST plugin host for OBS from here.

2. Configuring OBS for the ambiMIK-1[Top]

For OBS to be able to support the 4 ch USB audio interface from the ambiMIK-1, there are few settings to be configured first. To make sure the below steps are running smooth, make sure to connect the ambiMIK-1 to your PC/Mac before going further.

1. Configure OBS as a multichannel stream. Under OBS, go to File -> Settings - > Audio Tab. We'll select 4.0 as the audio configuration.

OBS settings multichannel

Note the general comment that we'll actually only feed 2.0 (binaural) with this configuration. Both Facebook/Youtube will take it as such.

2. Next we'll add the ambiMIK-1 as an ASIO audio input source to OBS. To do so, right click on the Source section of the GUI and select "ASIO Input" as per below.

OBS ASIO input

A dialog box will prompt you to name the source. We'll call it ambiMIK-1 for the purpose of this demo. 

3. Next stage is to configure the ASIO source. We'll select the miniDSP ASIO driver(previously installed) and follow the below example configuration.

ambiMIK asio properties

4. At this stage, the ambiMIK-1  should be live and ready to stream audio as you'll notice from the RMS meters in the Audio Mixer section. Make sure to use the ambiMIK-1 gain utility (see user manual) to modify the internal gain for proper signal as you speak/play music... The yellow section from -20~-10dB is what we'd typically recommend.

ambimik audiomixer

 You're now up and running with the ambiMIK-1 streaming into OBS.  Next stage is to configure the Dirac Live VST plugin so we're converting the ambisonic signal from the 4 mic capsules to a binaural signal one can enjoy with a headphone. 

3. Configure the ambiMIK-1 VST plugin[Top]

The next stage is to load the Dirac ambiSONIC VST plugin inside the VST host.

  1. Right on the ambiMIK-1 under the "Sources" section and select "Filters"

filters

2. Next, we'll add the VST plugin host as a filter by right clicking on the empty selection and click on Add - > VST 2.x plug-in as below.

VST plugin

3. Select the ambiMIK-1 plugin from the list.

VST plugin ambimik

NOTE: if you can't see the miniDSP ambiMIK-1 VST from this list, it's most likely because you didn't copy over the VST files in the correct folder as it will search the plugin in the following folders. Make sure to copy the VST files into one of these folders.

  • Windows (*.dll)
    • C:/Program Files/Steinberg/VstPlugins/
    • C:/Program Files/Common Files/Steinberg/Shared Components/
    • C:/Program Files/Common Files/VST2
    • C:/Program Files/Common Files/VSTPlugins/
    • C:/Program Files/VSTPlugins/
  • macOS (*.vst)
    • /Library/Audio/Plug-Ins/VST/
    • ~/Library/Audio/Plug-ins/VST/

4. The Dirac Research plugin should now be accessible by clicking on the "Open the plugin interface".

VST GUI

Make sure to configure the plugin to binaural audio output. See the ambiMIK-1 manual for other settings you might want to modify.  You can easily confirm that the VST plugin works as it should as only 2 channels will now become active under the Audio Mixer.

VST binaural output

4. Starting OBS streaming/Recording[Top]

- You're now up and running with the Audio side. You'll want to add your webcam or external video sources to the sources of OBS as per the manual of OBS.

- At this stage the steps to start your YouTube/Facebook/Twitch Live stream or recording a local stream will be similar to any stereo content. If you're not familiar with setting up OBS for Youtube/Facebook live, we recommend you follow some of the great step by step guides to get you started knowing this is a common question. Here are some great examples:

How to livestream on Youtube with OBS

How to livestream on Facebook live with OBS

 Make sure to google a bit more for better results.

Wrapping up [Top]

And this is a wrap on yet another interesting applications for the ambiMIK-1. We hope that it will help your future livestream concert, you next 3D immersive audio experience or maybe just learning a bit more about immersive audio!  Have fun and please send us feedback on this article and if you'd like to see more. We look forward to hearing from you!