You can reset your Philips Soundbar's audio settings back to the defaults. To complete this you will need the remote of the Soundbar.
How to reset audio settings of my Philips CSS soundbar?
Reset the Soundbar with your remote control
Once you have the remote please press the following buttons: BASS+, VOL-, and TREBLE+. Please press these in that order and within 3 seconds. The Soundbar will automatically turn off and back on again. The sound settings are now set to default. The picture below shows the remote and the order the buttons need to be pressed.