Samsung HW-S40T Full Manual page 12

 (Sound Control)
By pressing the button, you can select the desired audio mode. The desired item can be adjusted using
the Up/Down buttons. Each time the mode changes, the Multicolour LED blinks in white.
LED
Indicator
WOOFER (BASS) LEVEL

Push the button up or down to adjust the woofer (bass) between -6 to +6. To set the woofer (bass)
volume level to 0 (Default), press the button.
VOLUME

Push the button up or down to adjust the volume.
LED
Indicator
White Blinks X1
"Treble"  "Bass"  "Sync"
White moves to right X1
Volume Up
ENG - 12
White moves to left X1
Volume Down