Vehicle horn England, developed a standard electric car horn in 1910. Car horns are usually electric, driven by a flat circular steel diaphragm that has an electromagnet acting on it in one direction and a spring pulling in the opposite direction. The diaphragm is attached to contact points that repeatedly interrupt the current to that electromagnet causing the diaphragm to spring back the other way, which complete the circuit again. This arrangement opens and closes the circuit hundreds of times per second which creates a loud noise like a buzzer or electric bell, which sound enters a horn to be amplified. There
Horn (acoustic) the instrument more difficult to play. Acoustic horns are found in nature in the form of the burrows constructed by male mole crickets to amplify their song. "Gryllotalpa vineae" digs a carefully smoothed burrow with no irregularities larger than 1 millimetre. Its song is loud enough to make the ground vibrate; its 3.5 milliwatts of mechanical power delivers a peak of 92 decibels at a distance of one metre. The song can be heard up to 600 metres away. Horn (acoustic) An acoustic horn or waveguide is a tapered sound guide designed to provide an acoustic impedance match between a