An "audible signal" refers to a sound or noise that is used to convey important information or warn people about something. It is a signal that can be heard by our ears and it is meant to alert, notify, or create awareness. Full definition
A bell or some other audible signal is used to let the speed daters know it's time to switch partners. (articlesfactory.com)
This system alerts the driver with visual cues on the dashboard, as well as audible signals. (topspeed.com)
Using ultrasonic sensors, Park Distance Control automatically engages when you're in reverse, alerting you with audible signals when there's something up to 1.6 metres behind you. (vw.ca)