How do car horns make sound?

Question

How do car horns make sound?

Answer 1

Car horns have a flat circular steel diaphragm that has an electromagnet pulling on it and is attached to a contactor that repeatedly interrupts the current to the electromagnet, somewhat like a buzzer. There is usually a s***w to adjust the distance or tension of the electrical contacts for best operation. A spiral exponential 'snail' horn shape is built into the body of the horn to project the sound effectively.

Sound levels are about 107-109 decibels, and they pull about 5 or 6 amps. They can be used singly, but are more often in pairs to produce a chord consisting of two notes, sounded together. This only increases the sound output by 3 decibels, but the use of two differing frequencies with their beat frequencies and missing fundamental is more perceptible than the use of two horns of identical frequency, particularly where there is a high ambient noise level. Typical frequencies of a pair of horns of this design are 500 and 405-420 Hz (approximately B4 and G#4).

Some cars, and many motor scooters and motorcycles use a cheaper and smaller alternative design, that doesn't have any actual horn ducting and instead relies on a large flat diaphragm. They have a sound level of about 109-112 decibels, and current draw about 2.5 to 5 amperes. Again, they can be either single, or in pairs; typical frequencies for a pair are 420-440 and 340-370 Hz (approximately G#4-A4 and F4-F#4) for this design.

Answer 2

Small vibrating unit in the center of the unit is amplified as the sound waves are pushed through the circular horn section. Basically the same as a woodwind instrument , the vibrating mouthpiece is amplified as the sound passes through the length of the horn tubing .

Answer 3

Like a vibrating reed in a clarinet, or saxophone, for example, when you blow it vibrates, the body of a clarinet, or saxophone is the horn that amplifies the sound. In a electric horn electricity makes the reed vibrate (press horn button), and the horn body amplifies the sound.