SOYO SY-KT400 Dragon Ultra User Manual page 175

How to Adjust the Microphone Volume
You have to use the microphone when availing yourself of the "Echo"
function. If the microphone is on and is very close to the speakers, it
will cause feedback between the two. Also, unusual high frequencies
or buzzing sounds might be heard from the speakers. To avoid this,
you have to adjust the microphone volume in both recording and
playback. Sometimes you might have to adjust the main and Wave
volume as well. Please left-click the mouse to adjust the microphone
(MIC) in both Volume and Recording Control.
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