Audacity Forum

It is common on Vista and 7 that not all recording inputs are automatically enabled in the Recording tab. This means they are invisible in that tab, and also invisible to recording applications like Audacity. So you need to make them visible, then enable and make default the one you want to use, thus:

1. Right-click anywhere inside the Recording tab and choose "Show disabled devices" then right-click again and check "Show Disconnected Devices"
2. For a device having a physical input like line-in or microphone, connect the required cable and make sure it fits tightly - a physical device not connected may show as "currently unavailable"
3. Right-click specifically over the input device you want to record with (for example, line-in or "Stereo Mix"), and if visible, choose "Enable"
4. Right-click once again over the input device you want to record with, and choose "Set as Default Device"
5. Right-click once again over the input device you want to record with, click Properties then the Levels tab and ensure the volume slider is turned up
6. Optionally, right-click again over the desired device and choose "Set as Default Communication Device" - this is desirable if you are using a microphone for Skype or other VoIP program; also it is sometimes another required step to make the "stereo mix" device work
7. To prevent possible sample rate or recording channel discrepancies, right-click again and click Properties then the Advanced tab, and make sure the "Default format" matches both with the project rate bottom left of the Audacity screen, and with the number of "recording channels" in the Audio I/O tab of Audacity Preferences (Devices tab in current Audacity Beta); now click "OK"
8. Click the Playback tab of Sound, right-click over the "Speakers" or "Headphones" device for your computer sound device and set it as "Default Device" or "Default Communication Device" as required; then right-click and click Properties then the Advanced tab, and set "Default Format" to match with the settings in Step 7 above