After plugging the sensor in, it is necessary
to ensure that the computer sound card is not
monitoring an internal microphone instead. If it
is responding to sound, the internal microphone
should be muted or de-selected in the Windows
settings.
To find the WindowsTM settings follow Start
Menu—Programs—Accessories—Entertainment
—Volume Control. Once the Master Volume pane
opens, click on Options—Properties—Recording,
and here make sure that the microphone is
checked.