Virtual Audio Cable is a Windows multimedia driver allowing you to transfer audio (wave) streams from one application to another. It creates a pair of Wave In/Out devices for each cable. Any application can send audio stream to Out device, and any other application can receive this stream from In device. All transfers are made digitally, providing NO sound quality loss. VAC is a "wave-version" of the "MIDI loopback cable" like MultiMid or Hubi's Loopback drivers. If more than one applications are sending audio to VAC, it will mix all streams together. If more than one applications are receiving audio from VAC, it will share the same audio data between all targets.
VAC is useful to record application's audio output in real time (for example - Generator, Reality or other software synth), or transfer a sound stream to another application processing it. You can, for example, use two or more software audio generators/synthesizers/sequencors to produce audio streams sending them to VAC Out, and record the mixed stream from VAC In using any recording software - Windows Sound Recorder, Sound Forge, WaveLab, Cool Edit, Gold Wave, Cakewalk, Cubase etc.
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 "thief" an output sound stream from the application that doesn't allow to write it into WAV file directly. Unlike Total Recorder allowing you to simply save audio stream, VAC allows to route it in real time. 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.
