Car alarm the main reason why loud bass frequency sound (loud music, other cars or motorcycles with loud exhaust systems, thunderstorms, etc.) can set off car alarms. The second possible reason is that some parts of the alarm system may be improperly installed. Car alarm A car alarm is an electronic device installed in a vehicle in an attempt to discourage theft of the vehicle itself, its contents, or both. Car alarms work by emitting high-volume sound (often a vehicle-mounted siren, klaxon, pre-recorded verbal warning, the vehicle's own horn, or a combination of these) when the conditions necessary for triggering it are
Air horn or plastic horn or trumpet (called the "bell") attached to a small air chamber containing a metal reed or diaphragm in the throat of the horn. Compressed air flows from an inlet line through a narrow opening past the reed or diaphragm, causing it to vibrate, which creates sound waves. The flaring horn serves as an acoustic "transformer" to improve the transfer of sound energy from the diaphragm to the open air, making the sound louder. In most horns it also determines the pitch of the sound. When vibrated by the diaphragm, the column of air in the horn vibrates