SIRENS AND SPEAKERS AND THERE TYPES What is a Siren? Siren is a device which makes loud prolonged signal or warning sound, In more simple words it is a loud noise making device. Sirens are basically used in vehicles, specially emergency vehicles such as ambulance, fire trucks and police cars.
Sirens are of two types, "mechanical" and "electronic" sirens. What is a mechanical siren? Mechanical sirens or Q-Siren are designed for far distance as they have high tone range and they project sound in all directions. Mechanical Sirens pumps air, compressing and accelerating it to many miles per. Basically the siren which is widely used are mechanical sirens, they consists of an electric motor which turns a rotor or impeller, which spins inside a slotted drum known as the stator. Rotor works as a centrifugal fan which pulls air into the siren axially through the intake portion, which then blows it though the holes in the stator. Now, the rotor chops the incoming air flow into impulsive bursts. When rotor and stator holes aligns, a burst of air is forced through and the frequency of these air bursts is known as the pitch of the siren. Volume and pattern of sound waves can be controlled by the operator.