Hi Armos! Please ensure the firmware on your S40T Soundbar is up to date, as this will allow you to disable the voice guide feature. Ver. 1103 is available on Samsung.com
After your firmware update: With the Soundbar turned off, press and hold the source key on the Soundbar remote control for 5 seconds. The Soundbar will then turn of automatically. To re-enable the voice guide, repeat the above process.
I hope this helps. For further assistance, please contact Samsung Customer Support at 1-800-SAMSUNG. ^Gina