Sound setting only apply to TV mode, either LPCM 48/16 or Dolby 2.0 signal on optical/coaxial port. Those sound setting doesn’t affect surround 5.1 mode and CD mode.
Treble level
Set speakers treble level, total 15 level of 0.5dB each step.
Subwoofer level
Set subwoofer(s) level, total 15 level of 1dB each step.
Speaker sound timbre
Select speaker sound timbre : Natural, Vivid, Vocal and Comfort
Subwoofer bass
Select pseudo LFE channel bass effect : Off, Soft, Comfort, Strong
TV virtual 5.1 mode
Go to speaker setup page, enable TV play speaker. You can enable center speaker to have TV 3.1 sound, or enable rear speaker to have TV 5.1 sound.