Sony VGN-S380 VAIO User Manual page 192

Why is the stereo sound not recorded with a stereo microphone?
You may need to change the audio channel setting.
1.
Click Start and then Control Panel.
The Control Panel window appears.
2.
Click Sounds, Speech, and Audio Devices and then Sounds and Audio Devices.
3.
Click Volume under Sound recording on the Audio tab.
4.
Select Advanced Controls from the Options menu.
The Advanced button appears for Microphone Balance.
5.
Click the Advanced button and deselect the Mono Mic check box under Other Controls.
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