See also:

Office
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Multi-channel playback, surround
Choose between stereo and multi-channel playback, surround. Setting multi-channel playback, surround 1. "CD/Multimedia", "Radio" or "Settings". 2. "Tone" ...

Resetting the tone settings
1. "CD/Multimedia", "Radio" or "Settings" 2. "Tone" 3. "Reset" ...