The pot you refer to will adjust the exit entry tones but depending on the software version the R8 can actually be programmed for silent set at night.
On pressing part there are no sounds at all from keypad or speaker.
On later models the keypad bleeps once at the end of the setting period. The Texecom panels are one of the few that also do soft entry clicks after a part setting so if you get up early you dont get the full sound bleeps like other panels.
You would need engineering access to reprogramme this feature.
Alarm Engineer Bristol, July 2008