Virtual — Audio Cable

A Virtual Audio Cable (VAC) is a software-based audio bridge that allows you to route digital audio streams between different applications on your computer without physical hardware. It functions like an invisible digital patch cord, connecting one program's output to another's input. Core Principles & Operation

The software installs a virtual device driver that creates "Virtual Cables" within the Windows environment.

Virtual Endpoints: Each cable consists of a pair of endpoints: a playback (output) side and a recording (input) side.

Digital Loopback: Audio sent to the playback endpoint is internally transferred by the driver to the recording endpoint in real-time. virtual audio cable

Mixing & Splitting: Multiple applications can play audio to the same cable (which then mixes the streams) or record from the same cable (each receiving an identical copy).

Bit-Perfect Transfer: As long as no format conversion or volume adjustments occur, the audio transfer remains bit-perfect with zero quality loss. Common Use Cases Simple cable usage - Virtual Audio Cable - user manual

VAC Control Panel may show a new recording/capture stream indicating that a recorder application has connected to Virtual Cable 1. Virtual Audio Cable Virtual Audio Cable (VAC) A Virtual Audio Cable (VAC) is a software-based

The Verdict

Virtual Audio Cable is not for everyone. If you just want to listen to music, skip it.

But if you are a creator, a gamer, or a tinkerer, VAC unlocks a superpower: complete control over the audio traffic on your PC. It turns your operating system into a flexible audio studio, where sound can go anywhere you want it to.

Whether you choose the original VAC, VB-Cable, or VoiceMeeter, mastering virtual audio routing will permanently change how you think about sound on your computer. The Verdict Virtual Audio Cable is not for everyone

A Virtual Audio Cable (VAC) is a software-based driver that acts as a digital bridge, allowing audio to be routed between applications without physical hardware. It functions by creating "Playback" and "Recording" devices, enabling users to direct audio output from one application into the input of another, commonly for content creation or voice processing. For a detailed 2025 guide on setting up Virtual Audio Cables for streaming and production, read the full article at Jingyi Audio

What is a Virtual Audio Cable?

In the physical world, if you want to connect a guitar to an amp, you use a physical cable. You plug one end into the guitar (Output) and the other end into the amp (Input).

A Virtual Audio Cable does the exact same thing, but entirely inside your computer. It acts as a "virtual bridge" between software applications.

When you install one, your computer sees it as a new pair of audio devices:

1. The Output (The Speaker): This is where you send audio into the cable.
2. The Input (The Microphone): This is where you pull audio out of the cable.

By connecting software A to the "Output" and software B to the "Input," you create a direct pipeline for sound.

Popular options

• Virtual Audio Cable (VAC) — long-established Windows driver-based tool.
• VB-Audio Virtual Cable (VB-Cable) and VB-Audio Voicemeeter — free/paid variants with mixing features.
• JACK Audio Connection Kit — advanced routing, cross-platform, low-latency pro use.
• Soundflower (macOS, older) and BlackHole (modern macOS) — virtual drivers for macOS.
• Loopback (Rogue Amoeba, macOS) — paid, user-friendly GUI for complex routing.

2.1. The Driver Stack (Kernel Mode)

• WDM/KS Driver: VAC installs a Kernel Streaming (KS) filter driver that registers itself with Windows as an audio endpoint. It adheres to the Windows Driver Model (WDM) for audio.
• Port Class Driver: VAC uses the standard PortCls.sys system driver to interface with higher-level Windows audio subsystems (MMDevice API, WASAPI).
• Ring Buffer: Each virtual cable allocates a circular buffer in kernel memory. This buffer holds audio samples (PCM) as they travel from the playback side to the capture side.