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  Virtual Audio Cable 4.60
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  source code and other options
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Price: $49.00


Virtual Audio Cable software allows you to transfer audio (wave) streams between applications and/or devices.

It creates a set of virtual audio devices named "Virtual Cables", each of them consists of a pair of the waveform input/output endpoints. Any application can send (play back) audio stream to an output side of a cable, and any other application can receive (record) this stream from an input side. All transfers are made digitally, providing NO sound quality loss (a bitperfect streaming).

VAC behavior is similar to "Stereo Mix" ("What You Hear", "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 Vista/Win7/Win8/Win10, there could be better to try to enable it in your audio adapter.

If more than one applications are sending audio to Virtual Cable device, VAC mixes all streams together. If more than one applications are receiving audio from Virtual Cable device, VAC distributes the same audio data among all targets.

VAC is useful to record application's audio output in real time (audio player, instant messenger or software synthesizer), or transfer a sound stream to another application processing it. You can, for example, use two or more software audio players/generators/synthesizers/sequencers to produce audio streams, sending them to Virtual Cablet device and record a mixed stream from the same Virtual Cable device, using any recording software - Windows Sound Recorder, Audacity, Sound Forge, WaveLab, Adobe Audition (formerly Cool Edit Pro), Gold Wave, Cakewalk/Sonar, Cubase/Nuendo etc.

With an ASIO wrapper like ASIO4ALL, you can use VAC with ASIO supporting applications.

If you use an audio encoder application that encodes a stream coming from a sound card, you can use VAC to supply such encoder with a stream produced by other application.

You can use VAC to capture an output sound stream from the application that doesn't allow to write it into WAV/MP3 file directly. Unlike Total Recorder allowing you to simply save audio stream, VAC allows to route it in real time.

VAC can be used with network audio/video broadcasting software like SAM Broadcaster or OBS Studio by Open Broadcaster Software, software-defined radio (SDR) applications like PowerSDR by FlexRadio. If you are using some Voice Over IP (VoIP) and/or Internet Telephony applications like Skype, you can use VAC to record your calls and conversations.

VAC needs no hardware audio card, it is a "virtual audio card" itself.

Since VAC 4 is an NT WDM driver, there are some benefits but some (generally older) applications that use MME (waveIn/waveOut) interface can work better with the older VAC 3 version. This version also supports Windows 98/ME.

If you need to simply share your In/Out wave ports among several applications under Windows 2000 and earlier Windows versions, take a look to the Wave Clone software.


  • Local (console) session only (does not work via Remote Desktop or Terminal Services).
  • Windows 5.x, 6.x and 10.x platforms (32-bit and 64-bit).
  • Up to 256 virtual cable devices (some systems limit number of MME devices).
  • 1..20 milliseconds per interrupt/event.
  • 1..100 pin instances.
  • Almost any of fixed point PCM audio formats (1000..384000 samples per second, 8..32 bits per sample, 1..8 channels). Floating point formats are not supported.
  • Almost no sound latency with maximal interrupt/event frequency.
  • RTAudio support with notification events, clock and position registers. Clock registers are bound to Virtual Cables so all streams in each cable are coherent.
  • Unlimited number of Kernel Streaming clients connected to each port.
  • Signal mixing (with saturation) between output port clients.
  • PCM format conversion (sampling rate, bits per sample, number of channels).
  • Volume control features (both attenuation and boost).
  • Channel scattering/gathering mode.
  • Watermark control technique to improve stream stability with unstable applications.
  • Stream buffering technique to partially compensate bad application buffering algorithms.
  • Control Panel application to configure cables and watch their state.
  • Audio Repeater application that transfers from any recording to any playback device.


System requirements
  • Win 5.1..10.x (Windows XP/2003/Vista/Server 2008/Win7/8/8.1/10) platforms, 32-bit or 64-bit.
  • Any hardware suitable for a host OS.
  • A native hardware or a fully virtualized environment (VMware Server/Workstation, VirtualBox, VirtualPC etc.). With partial virtualization (VPS, Virtuozzo etc.), only host OS installation is possible (see VAC user manual for details).
  • Hardware and OS must be suitable for real-time audio processing. You can check your system with LatencyMonVoIP and tune it using common guidelines.


Important notes
Please note that VAC is not a self-sufficient software that may work alone just under operating system control. VAC is a tool. Like hardware tools (for example, a screwdriver or a saw) that are used only together with other objects (screws or boards), VAC should be used only together with audio applications to route audio streams produced or consumed by these applications.
VAC package is distributed as a ZIP archive. Simply unpack it into an empty folder, run setup.exe application and follow the instructions displayed. If you use VAC for the first time, please read the readme.txt and vac.chm files before installation. If you have already installed previous version of VAC 4, don't forget to uninstall it before installation.


Source code and other options
VAC is a WDM driver miniport written entirely in MS C++ using object-oriented technology. No external assembly files or additional driver development tools like VtoolsD are used.

VAC also supports a custom (proprietary) version creation to be used together with a particular application only. Each of custom versions has an unique key to identify its "native" application. This "native" application uses a special way to open the driver. Such opening way is called a "open in the native mode". When the driver is opened in native mode, it transfers audio signal without any limitations. If not, it adds a noise to the signal to prevent unauthorized usage.

Please note that custom version of VAC has the same functionality as the common version. Customization includes only unique names and unique key, not additional custom functionality.

To purchase VAC sources, custom version and multiply license, contact us.