How to Capture Audio from a Specific VM in OBS

Capturing audio from a specific virtual machine (VM) without recording your entire system audio is a crucial setup for streamers, tutorial creators, and security researchers. This guide provides a direct, step-by-step walkthrough on how to isolate and capture sound from a single VM instance using OBS Studio’s native Application Audio Capture feature. By following these steps, you can route your VM’s audio directly into OBS while keeping your desktop notifications, music, and voice chat apps completely silent on your recording or stream.

Step 1: Prepare Your Virtual Machine

Before configuring OBS, you must ensure your virtual machine is running and actively capable of producing sound. 1. Launch your virtualization software (such as VirtualBox, VMware, or Hyper-V) and start your specific VM instance. 2. Inside the guest operating system, play a continuous audio source (such as a YouTube video or a system test sound) so you can visually monitor the audio levels in OBS later.

Step 2: Add the Application Audio Capture Source in OBS

OBS Studio (version 28.0 and newer) includes a native tool to capture audio from individual applications. 1. Open OBS Studio. 2. Locate the Sources dock at the bottom of the screen. 3. Click the + (Add) icon at the bottom of the Sources dock. 4. Select Application Audio Capture from the list. 5. In the pop-up window, name the source (e.g., “VM Audio”) and click OK.

Step 3: Target the Virtual Machine Process

Now you must tell OBS to target only the window process of your virtual machine. 1. In the properties window that appears, locate the Mode dropdown menu and select Capture specific window. 2. Click the Window dropdown menu. 3. Select your virtual machine’s process from the list. * For VirtualBox, look for the process running the guest OS window (usually named VirtualBox VM or similar). * For VMware, look for vmware-vmx.exe or the specific window title of your running VM. 4. Leave Window Match Priority at its default setting (“Match title, otherwise find window of same type”) and click OK.

Step 4: Isolate the Audio in the Mixer

To ensure you are only capturing the VM audio and not duplicating it through your system audio, you must disable global desktop audio. 1. Look at the Audio Mixer dock in OBS. You should now see a dedicated volume slider for your “VM Audio” source. 2. If you have a global “Desktop Audio” source active in the mixer, click the speaker icon next to it to mute it, or remove it entirely from Settings > Audio > Global Audio Devices. 3. Verify that the green and yellow level bars are bouncing only under your new VM Audio source when sound plays inside the virtual machine.