Vehicle horn horn. Bicycles often have a classic "bulb horn", operated by squeezing a rubber bulb attached to a metal horn. Squeezing the bulb forces air through a steel reed located in the throat of the horn, making it vibrate, producing a single note. The flaring horn matches the acoustic impedance of the reed to the open air, radiating the sound waves efficiently, making the sound louder. Other types of horns used on bicycles include battery-operated horns (sometimes even car horns on 12-volt circuits are incorporated) and small air horns powered by a small can of compressed gas. Oliver Lucas of Birmingham,
French horn the assistant is asked to play a passage after resting a long time. Also, he or she may be asked to enter in the middle of a passage, exactly matching the sound, articulation, and overall interpretation of the principal, thus enabling the principal horn to rest a bit. The French horn was at first rarely used in jazz music (Note that colloquially in jazz, the word "horn" refers to any wind instrument). Notable exponents, however, began including French horn in jazz pieces and ensembles. These include composer/arranger Gil Evans who included the French horn as an ensemble instrument from the