Virtual Audio Cables and Streaming

ed. I have an updated article for this setup as I’ve moved to VB Cables, check it out!

In this article I will show you how to use Virtual Audio Cables to solve a common problem when streaming to a site like Twitch. There are times where you may have multiple sound sources, and you only want certain ones to go to your stream. There also may be instances where you want certain sound streams merged together so that they can all hear each other. We will go over how to stream game audio to your stream, but not stream your Mumble/VOIP  as well.

This is where the Virtual Audio Cables come into play. We will use them to separate the different sound sources. There is a handy program, VAC, that will install the Virtual Audio Cable drivers for you and the other tools required to set this up. For this example we will install two new VAC’s.


In this image you set the amount of cables you need in the top left, and that is really all the configuration we need to do here. From here now open the playback devices menu, you can quickly find this by right clicking on the volume icon in your systray.



In the first image you can see the two new lines that we installed. For this example I made Line 2 the default device. This means all apps will use this Line by default unless otherwise specified. This means things like web pages, music applications/streaming services, etc. I set my headset as the default communication device so Windows knows which device to use because I have multiples available in my system. I recommend setting all your settings explicitly, so you do not have to question where anything is sending its audio.


Now log into your game of choice, in this example I used World of Warcraft. Head to the sound settings and select Line 1. Now to setup Mumble.


Here we set Mumble to directly use my headset, by default Mumble is typically set to use the Default Windows device. Set this directly to the device you use for listening and recording. Now we setup our streaming app, in this case OBS. Note: To see these menus, you may need to check the advanced checkbox towards the bottom of the window if you have not already done so.


In OBS we configure the Audio to be streamed to just be what is playing over Line 1. We then set the recording device directly to what we are using. Now we are going to put this all together using the Audio Repeater software that is also installed when you install VAC.


This is what the Audio Repeater interface looks like. Launch the MME version not the Kernel version of the tool. This application is basically a bunch of software mixing boards. We are going to use multiple instances of this Audio Repeater app to accomplish what we want to put on our stream. Now this is where you start to have some freedom in how you want to configure this, let’s review some example configurations.

  1. Send only game audio to your stream. Mumble will go to your headset, but will not be transmitted to your stream. Also, other applications will go to your headphones, and not your stream.
  2. Send game audio, and other applications to your stream. Mumble will only go to your headset.

Let go over how you would setup the Audio Repeaters for these two examples.

Configuration 1.

1 – Audio Repeater: Wave In – Line 1, Wave Out – Headset/Speakers
1 – Audio Repeater: Wave In – Line 2, Wave Out – Headset/Speakers

This separates the audio into two distinct channels. Line 1 is configured to be picked up by OBS, and is now also setup to be sent to your headset/speakers. This allows your stream, and yourself to hear Line 1 (game audio). We already manually configured Mumble to be set directly to our headset/speakers. Line 2 will be other audio on your system, and it is now output to your headset/speakers.

Configuration 2.

1 – Audio Repeater: Wave In – Line 1, Wave Out – Headset/Speakers
1 – Audio Repeater: Wave In – Line 2, Wave Out – Line 1

This configuration shows how you can easily flip things if you want to stream the audio from a music app or a video, etc. These applications will all use Line 2 because we set it as the default device. We leverage this repeater to merge it with Line 1, and now our stream and we can hear it.

Microphone configuration. This really depends on the user. I’ve tried it two different ways. One, a push to talk for each application. One button to talk to stream, one button to talk to Mumble. You could also configure it so you PTT to send to Mumble, and regular talking over the Mic goes to your stream. That is really up to your preferences, and hopefully if you are reading this you know how to set that up how you prefer.


For Questions/Comments, message me on Twitter @Nicarras.

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