Vehicle horn of vehicle horns are used by percussionists as sound effects, or even melodically, in musical works. For example, George Gershwin's 1928 orchestral work "An American in Paris" calls for the use of 4 taxi horns. György Ligeti's opera "Le Grand Macabre" features two "Car Horn Preludes" scored for 12 bulb horns, each one tuned to a specific pitch. Klaxon is a trademark for a brand of electromechanical horn or alerting device. Mainly used on cars, trains and ships, Klaxon horns produce an easily identifiable sound, often transcribed onomatopoeiacally in English as "ahoooga." Like most mechanical horns, the klaxon has largely
Sound from ultrasound to have sounds audible to only one person, or that which a group wants to listen to. The navigation instructions for example are only interesting for the driver in a car, not for the passengers. Another possibility are future applications for true stereo sound, where one ear does not hear what the other is hearing. Directional audio train signaling may be accomplished through the use of an ultrasonic beam which will warn of the approach of a train while avoiding the nuisance of loud train signals on surrounding homes and businesses. This technology was originally developed by the US Navy