<P> A double reed is a type of reed used to produce sound in various wind instruments . The term double reed comes from the fact that there are two pieces of cane (or, less commonly, some other material) vibrating against each other . A single reed consists of one piece of cane which vibrates against a mouthpiece made of metal, hardened rubber, resin, or some other material . The term double reeds can also refer collectively to the class of instruments which use double reeds . </P> <P> There are several differences, the most obvious being size, between various types of double reeds, for example between that for a bassoon and that for an oboe or a cor anglais (sometimes called an English horn). </P> <P> Typically, Arundo donax cane is used for the making of double reeds . For bassoon reeds, tubes of this cane are first split lengthwise then gouged to a certain thickness . The chosen piece of cane is then cut to shape and the centre portion is thinned (profiled). The cane is folded end to end to form the two blades of the reed . The unprofiled end of the cane is shaped into a tube with the aid of a mandrel and bound with three (or four in some reed making techniques) strategically placed wires . A turban made out of thread is added on the third wire . It provides a hand hold for the reed that isn't a sharp wire . The folded tip is cut off to allow the blades to vibrate and final adjustments to the interior of the reed using a reamer, and to the exterior using a reed - scraping knife, are carried out . The reed is then ready to fit to the bocal of the bassoon . Note that there are many schools of thought and processes for making reeds . </P>

What is an example of a double reed instrument