YT1DL Only Digital

Virtual Audio Cabel (VAC) Setup

Virtual Audio Cable (VAC) is a third-party software program that allows the rerouting and the emulation of a sound card in software rather than having to use a second sound card for audio analysis or use with digital mode programs such as MixW and Dream. There are some significant advantages to using VAC over a second sound card.

•    The entire audio stream is maintained in the digital domain - there is no multiple conversions of the signal from digital to analog and from analog to digital.
•    There are no external cables to degrade the sound quality or possibly pick up RFI.
•    A computer PCI, Firewire or USB slot is not used.

Configuring VAC 4.0x

There are several steps involved in getting VAC installed and working properly with SDR transceiver software. Below is a summary of the steps required.

1.    Obtain and install VAC 4.0x on the same computer that is running SDR transceiver software from
2.    Configure VAC "cables"

Step 1. Install VAC 4.0x as per the installation directions. If VAC was previously loaded, you must first uninstall all versions before installing a new version of VAC 4.0x

Step 2. Once installed, set up a pair of VAC audio "cables" for use with SDR transceiver software by opening the VAC Control Panel.

Next step is to set input (recording) mixer. In same window go to Options and then Properties. As a mixer device choose audio input. Mixer console will change into Recording Control. Mute every signal source except Recording and Line Volume.


By default only one audio cable is defined. You will need to create two cables by changing the driver parameters to 2 cables then click SET and Restart. Highlight the appropriate cable and change the values to match the figure above. In the "Ms per int" box enter a value between 1 and 20 ms. The lower the value, the smaller the VAC audio buffer. In the example above, 7 ms was selected. Depending on your computer setup you may have to adjust this value to prevent the audio from dropping out or "popping".

NOTE: After completing all of the necessary changes, click on Set for each cable when completed.
NOTE: Repeat these changes for the second audio cable as well.
NOTE: Do NOT check the Volume Control box in the VAC control panel. This enables the Windows Mixer and can cause unpredictable results.
NOTE: VAC is not free software!