I was recently trying to record some internet radio at work using Audacity. I say trying because it would not capture the audio despite my mucking with every possible setting. There was simply no option to record "What you hear" or "Stereo Mix". These were options I was accustomed to seeing on my home machine so why were they missing? Was my work PC somehow locked down?
Countless Google searches later I came across a posting in a tech forum where someone figured out that the feature was actually still available -- it's just disabled. Most audio drivers are built to do everything. It's less expensive to have a do-it-all driver with features disabled in a config file than to design a driver from scratch with limited features. As a result, many of the commodity PCs with onboard audio have their "Stereo Mix" feature disabled. They assume you are going to steal audio streams; how nice of them.
We can change the situation. We just need to edit a config file and reboot. The process is generally the same for any AnalogDevices-based audio chipset...
1. Go to your PC manufacturers web site and download the audio driver that shipped with your machine.
2. Be careful to get the correct driver for your current OS. For example, your PC may have shipped from the manufacturer with Windows XP but maybe now it has Windows Vista. Get the correct one.
3. Save this driver and unzip the contents somewhere you'll remember.
4. Go to the folder where you unzipped the driver contents. Drill down to C:\...i386\SMAXWDM\W2K_XP or whatever the path is for your driver.
5. Look for a file called ADIHDAUD.inf and make a backup copy of it. I called mine "ADIHDAUD_inf.org" so I know that it is the original file. This is insurance in case we make a mistake in our upcoming edits.
6. Open ADIHDAUD.inf in Notepad. Time to make some changes.
7. On line 303 I made a change
before: HKR,AD1983\\Disable, OutR, 1, 01
after : HKR,AD1983\\Disable, OutR, 1, 00
8. On line 304 I made a change
before: HKR,AD1983\\Disable, MonR, 1, 01
after : HKR,AD1983\\Disable, MonR, 1, 00
9. On line 352 I made a change
before: HKR,AD1984\\Disable, MonR, 1, 01
after : HKR,AD1984\\Disable, MonR, 1, 00
10. By changing that 01 to a 00 you are now going to have an install that includes the Stereo Mix feature.
11. Click Save (not Save As) to keep the edits we just made. ADIHDAUD.inf should now be updated
12. Uninstall the current SoundMAX Audio driver. When you reboot Windows will say that it found new hardware (sound card) and try to start the driver install process. Just click Cancel.
13. Install the driver you downloaded and unzipped from step 3. It's usually a setup.exe file
14. Reboot to make sure the modified install worked