An instrument for producing musical tones and for ascertaining the number of sound waves or vibrations per second which produce a note of a given pitch. The sounds are produced by a perforated rotating disk or disks. A form with two disks operated by steam or highly compressed air is used sounding an alarm to vessels in fog.
This is an OUTPUT DEVICE installed at the protected premises to audibly signal an alarm to the building's occupants.
A sound signal which uses electricity or compressed air to actuate either a disc or a cup-shaped rotor.
a warning signal that is a loud wailing sound
an acoustic device producing a loud often wailing sound as a signal or warning
A noisemaking device which sounds when the alarm system detects a breach of security.
Audible device alerts family and neighbors of an alarm condition.
A siren is sounded to indicate there is an inquiry into the running of the race.
Noise generating device usually installed in the engine compartment of the vehicle. It is responsible for generating the "chirps" you hear, as well as the six tones you hear while the alarm is triggered.
A special device for making a very loud and long signal or warning sound
A warning device that provides a high-pitched or an alternating high-pitched and low-pitched wailing sound, used by emergency vehicles.
A siren is a loud noise maker. The original version would yield sounds under water, suggesting a link with the sirens of Greek mythology. Most modern ones are civil defense or "air raid" sirens, tornado sirens, or the sirens on emergency service vehicles such as ambulances, police cars and fire trucks.