So you want to split certain audio sources so you can hear them but without the viewers on the stream hearing this, and got recommended to use something like VoiceMeeter Banana? But due to the somewhat complicated (advanced) setup you do not want to use this? This guides will explain how you can split audio so only you can hear it but your viewers cannot by only using a single Virtual Audio Cable.
Start by downloading CABLE (VB-CABLE Virtual Audio Device) offical website and install it. You get one virtual audio cable for free, which is enough for this guide but if you need more, you can get up to two extra virtual cables if you Donate to the developers. After you installed CABLE, please do reboot your computer to properly setup the new virtual audio device.
After the reboot the first thing you are going to do is to set the newly created audio device, CABLE INPUT (VB-AUDIO Virtual Cable) as your default output device in Windows. For Windows 10 users, right-click the speaker icon in the system tray and select "Open Sound Settings". In here you can set the cable as your audio device, and make sure that the volume is set to 100 as this will be used for OBS Studio or Streamlabs OBS and will not be your headphones or speaker volume!
For those that would like to open the older Windows Sound Panel they can easily reach this by selecting "Sounds" instead of "Open Sound Settings" and navigate to the "Playback" tab.
Now that the virtual audio cable is your default device in Windows, you need to patch this audio also to your headsphones or speakers to hear it. Open the Windows Sound Control Panel and navigate to the "Recording" tab, as we will use the other end of this virtual audio cable to patch this to your headset. Select and open the properties of CABLE Output (VB-AUDIO Virtual Cable) and navigate to the "Listen" tab. In here check Listen to this device and select the headset or speakers you want to use. Now if you play audio, YouTube video for example, you should now hear it again!
It might now to be a bit more difficult to adjust your own volume on the fly as you generally do not want to adjust the volume of CABLE as this will also lower the total volume the stream receives. Via the properies of your headset or speakers via the Windows Sound Control Panel you can adjust your own volume on the "Levels" tab.
To capture the desktop audio in OBS Studio or Streamlabs OBS is not changed and you will either select Default or CABLE Input (VB-Audio Virtual Cable as your Desktop Audio Device to capture all audio that is send to the virtual audio calble, like alert sounds and other application that do not have a selectable audio output.
Now anything that you send directly to the headphones or speakers, wherever possible, you will hear but the viewers on your stream will not. For example in Discord, a popular VOIP application, you can manually set the output device you want to use and thus in this case select your headphones or speakers as device and do not use default. As default will be the virtual audio cable that is being captured by the streaming application.
Now you want to hear the audio of a certain application, Spotify (Windows Store version) for example, without the viewers on stream hearing this but the application does not have a selectable output device in its settings. Luckely since Windows 1803 (April 2018) update you can enforce the output device that an application needs to use, without relying on complicated or unstable 3rd party audio routing applications to enforce an output. Start by opening the Windows Sound Settings, by right-clicking the speaker icon in the system tray and select "Open Sound settings". Then scroll down till you see "App volume and device preferences" which you need to click on.
In here you have various options per application to enforce an output or even the input device. For this example, we enforce Spotfy to our headphones or speakers so we can hear Spotfy music but the viewers cannot. If an application is not listed you want to enforce the output, let it play some audio as it will appear then!