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,
Alarm Will Sound current events, if only for two hours.”) "Canzonas Americanas", their 2012 release on Cantaloupe features music by Derek Bermel whose eclectic approach draws on the musical traditions of Europe, North and South America, and Africa. The San Francisco Classical Voice says about Alarm Will Sound, "It's hard to imagine another ensemble that could handle the vast range of musical ingredients – including rock, Conlon Nancarrow–style layered rhythms, jazz, and especially world music influences ranging from Brazilian choros to West African balafon – that inform this wildly eclectic new document…" The Guardian says, "Bermel tends to build his music layer by