Virtual Audio Cable (VAC)

With Virtual Audio Cable (VAC) free utility, you can connect Windows PC audio applications, routing audio signals between them.



You definitely know that traditional hardware audio devices (CD/LP player, FM receiver, equalizer tool, amplifier, etc.) may be connected by electrical (analog or digital) cables.

It provides a set of virtual audio devices named Virtual Cables. The "Virtual Cable" term is used only in the VAC description; actual device/endpoint names are different.

You could create the same path, connecting the analog output of any audio adapter (sound card) to its own analog input by a plain electric cable. Then, you can select playback and recording endpoints in source and destination applications, so they become connected.

This software performs such signal transfer completely inside the computer, with no audio hardware, and with no quality loss (if no format conversion and/or volume control are involved).

Download Virtual Audio Cable for Windows PC now!

However, the digital audio signal produced by the source application will come through a digital-to-analog converter, then through the electric cable, then through an analog-to-digital converter, and finally be recorded by the destination application.



Therefore, double digital-to-analog and analog-to-digital conversions are performed in case of such a connection, and audio quality is degraded.

VAC behavior is similar to the "Stereo Mix" ("What You Hear" or "What U Hear") feature of some hardware audio adapters (cards). But it is only similar, not equivalent.

If you simply need a function like "Stereo Mix" under Win7/Win8/Win10/Win11, it could be better to try to enable it in your audio adapter.

How to Use Virtual Audio Cable (VAC)

1. Install this tool and restart your computer if required.
2. Open VAC Control Panel and create at least one virtual cable (Line 1).
3. Set the first application’s audio output device to “Line 1 (Virtual Audio Cable)”.
4. Set the second application’s audio input device to “Line 1 (Virtual Audio Cable)”.
5. Play audio in the source application and verify it appears in the destination application.
6. Adjust buffer size and latency settings in VAC Control Panel if needed.
7. Use additional virtual lines if you need to route multiple audio streams simultaneously.

No audio hardware required
You need no audio hardware (sound adapter/card), either built-in or external, to use VAC for digital audio transfer. Audio hardware is required only to hear the results or to record signals from external sources. On a computer with no audio adapter (card), you still can use VAC to record audio signals produced by applications (for example, testing audio broadcast on a virtual server).

Control panel application
VAC Control Panel application allows you to change the number of Virtual Cables, view/modify VAC driver and cable settings, and watch for cable/stream activity.

Device-to-device audio transfer
Virtual Cable devices (endpoints) allow you to organize application-to-application audio transfer only. To perform the endpoint-to-endpoint transfer, use the Audio Repeater application included in the product package.

Driver-based solution
The app contains a Windows WDM/KS virtual device driver that creates virtual audio devices. This driver is a kernel-mode module and needs to be installed with administrator rights. Being a WDM/KS filter, it represents the lowest-level audio layer in Windows. It can be effectively used by any upper-level layer (KS-aware applications, WASAPI, MME or DirectSound subsystems, ASIO wrappers, and so on).

Comprehensive user manual
It user manual is included in the free trial package available on the download page. It contains many details useful for a better understanding of the product and for using it correctly. You don't have to install the trial version to open and read the user manual. Just download the ZIP archive, open it to see the contents, and double-click on the file named "vac" marked by the question mark icon (the "chm" extension).

Features and Highlights

• Windows 11, 10, 8.1, 8, 7 (32-bit and 64-bit).
• Up to 256 Virtual Cables, allowing to transfer of up to 256 independent audio signals at the same time.
• Latency can be reduced to 0.5 milliseconds.
• Almost any of the fixed-point PCM audio formats (1000..384000 samples per second, 8..32 bits per sample, 1..32 channels).
• PCM format conversion (sampling rate, bits per sample, number of channels).
• RT Audio (WaveRT) protocol support with notification events, packet mode, clock, and position registers. Clock registers are bound to Virtual Cables, so all streams in each cable are coherent.
• An unlimited number of Kernel Streaming clients. You can share each Virtual Cable between any number of KS-aware audio applications or ASIO wrappers.
• Signal mixing from all streams of each Virtual Cable, allowing to mix signals from several applications in real-time.
• Volume control features (both attenuation and boost).
• Channel scattering/gathering mode. Using KS-aware applications, you can map particular channels in a stream.

Applicability

VAC can be used with a wide range of audio software and application categories, including:

Internet Telephony / VoIP / SIP / Voice Messaging
Compatible with communication platforms such as Viber, Zoom, Discord, Ventrilo, and MicroSIP for routing call audio between applications.

Live Mixing and DJ Software
Works with tools like vMix, Mixxx, VirtualDJ, and VoiceMeeter Banana/Potato to manage and redirect live audio streams.

Live Broadcasting
Integrates with streaming and broadcasting software including OBS Studio, Wirecast, VidBlasterX, and SAM Broadcaster.

Speech Synthesis and Recognition
Supports text-to-speech and speech-to-text engines such as Google TTS/STT and Dragon NaturallySpeaking for audio input/output routing.

Software Synthesizers and Digital Audio Workstations (DAWs)
Compatible with professional music production tools like Ableton Live, ACID, AudioMulch, Band-in-a-Box, Bidule, Cakewalk/Sonar, Cubase, FL Studio, GarageBand, Logic, MiniMoog, n-Track, Nuendo, Reaktor, REAPER, Reason, Samplitude, Traktor, and Vegas.

Audio Editors and Recorders
Functions seamlessly with editing software such as Audacity, Adobe Audition, GoldWave, WaveLab, and Sound Forge.

Virtual Machines
Enables audio routing inside environments like VMware Player/Workstation, VirtualBox, and Hyper-V.

Amateur and Software-Defined Radio (SDR)
Useful for radio communication software including Flex Radio, PowerSDR, HAM Radio Deluxe, HamSphere, HDSDR, Fldigi, SDR-Radio, WSJT-X, and JTDX.

Audio Application Development
Ideal for developers who need to monitor audio operations, analyze playback data, or inject specific audio streams for testing and recording purposes.

Alternatives 

VoiceMeeter – A virtual audio mixer and routing tool that offers advanced control over multiple audio inputs and outputs.

VB-Cable for PC – A simpler virtual audio cable solution for basic routing without extensive mixing features.

ASIO4ALL – A universal ASIO driver that improves audio performance and routing for low-latency applications.

PROS

• High Audio Quality Routing
• Minimal Latency Performance
• Customizable Audio Channels
• Compatible with Most Audio Apps
• Easy Installation Process

CONS

• Complex Setup for Beginners
• Limited Free Version Options
• Occasional Audio Lag Issues
• No Built-In Audio Effects
• Resource-Intensive on Low-End PCs

Note: Limited functionality in demo version.