How to FIX Crippled Stereo Mix on a Laptop

Recently some manufacturers of notebook computers, particularly those produced or based in China, have been shipping laptops with the stereo mix feature disabled in firmware. A lot of discussion can be found online about it. On my particular ThinkPad, it can be enabled somewhat by a registry hack, but you have to disable the onboard microphone in order to use stereo mix, so it's not a great fix.

I think the manufacturers really had no idea how much they'd aggravate a whole swath of their users with this policy. I've read complaints ranging from disappointment over no longer being able to do karaoke with a newly purchased laptop, annoyance at not being able to do advertising voice-overs, to some real ire at not being able to perform audio mixing and recording by a church music director.

Virtual Audio Cable (VAC) has a reputation for being a tough program to learn and use. It can be. If you like to dig deep into the plumbing, there's enough theory, principles, background, associated content, and practices in the Help Guide to satisfy and bemuse. Here we're taking a more direct approach. We'll talk about what we need to set up VAC on a laptop that lacks the stereo mix feature and how to use it to record one or more sound sources, including "what u hear" and microphone mix, on a notebook.

VAC is a compact 272 KB download. You can find the download link here. You can read the entire page if you wish, or you can scroll down and click the link to download the 32-bit or 64-bit version. The version we tested was 4.09 32-bit, and the ThinkPad is running Vista Home Premium.

There are several files and a couple of folders present when the distribution file is unzipped. Of interest to us are "vac.chm" which is the compiled help file and the two executable files - setup.exe and setup64.exe.

I found no undesirable stipulations in the license. On the second setup screen, there is a check-box beside "I am an advanced user." You should only check this if a previous installation failed on your laptop. It also warns that previous versions, if any, should be uninstalled before continuing. The third image below is a warning from Vista that it can't verify the "publisher of this driver software." Microsoft still makes it impossible for private, single developers to get certificates, so you can click "Install anyway" and continue.

The final message is a small dialog that says, "Installation completed successfully."

The image below shows what is added to the Vista Start menu after VAC installation.

We can't completely avoid all program theory here, but the reason it's called "Virtual Audio Cable" is because it acts like what we used to call a "patch cord." It connects the output of something to the input of something else. In our case, we want it to connect the output of a sound producer on the laptop to the input of some recorder. We further want to connect more than ONE sound source to the recorder.

So don't feel overwhelmed when you see this startup screen.

We'll be leaving this control panel open and looking at it from time to time, but for now, let's adjust the primary settings. Currently recommended settings are:

• Maximum instances - 20
• Milliseconds per interrupt - 5
• Sampling rate range - 44100 to 48000
• Bits per sample - 8 and 6
• Number of channels range 1 and 2
• Stream format limiting - Cable range

The trial version is limited to two instances, or cables.

The next step is to find out if it's going to work on your notebook. To do this, we need to play back some sounds from an application that will recognize "Virtual Cable 1." This is not Windows Media Player, as it writes directly to Vista’s sound mapper service. Instead, we’ll use Nullsoft’s popular and free (for the basic version) Winamp player application as our sound source.

To redirect Winamp’s output to VAC, click Options, then Preferences. In the Preferences dialog, scroll down in the left-hand pane and find the Plug-ins section. Then click on Output. In the right-hand pane, click on “Nullsoft DirectSound Output” and then click Configure. In the “DirectSound output settings” dialog, under the Device tab, click the blue horizontal bar and select “Line 1 (Virtual Audio Cable).” Then click OK and Close.

At this point, I had to close and restart Winamp before the connection showed in the VAC Control Panel.

The images below show VAC without a connection and VAC with a song being played in Winamp. Notice that the rest of the first line (Cable 1) is now filled out.

But there’s no sound! That’s right. We haven’t established a recording connection yet, but VAC includes a utility program called Audio Repeater that can intercept the stream and play what’s passing through the cable.

Start Audio Repeater and set “Wave In” to “Line 1 (Virtual Audio Cable)” and “Wave Out” to “Microsoft Sound Mapper.” Then start your music player application, click the Start button in Audio Repeater, and you should have audio.

If using the trial version, you’ll hear a female voice saying “Trial” frequently. This is a gentle urge for us to register the program.

At this point, we’ve found out if VAC is compatible with our hardware. Audio Repeater’s playing the music stream tells us that the virtual cable is indeed connected to the sound source. Since we’re interested in both recording and mixing sources, let’s now see if VAC will work as the default audio handler on the laptop.

For this, you’ll need to click the speaker icon in the System Tray and select “Recording Devices.” Under the Recording tab, click “Line 1 – Virtual Audio Cable” and click “Set Default.” If using the trial version, which you should be at this point, you’ll see the level indicator bumping upward irregularly. This is VAC repeating “Trial” over and over (whether you can hear it or not).

To hear it, start up Audio Repeater and click “Start.”

Next: Testing Recording, What U Hear, Conclusion, Product Link, and Further Reading