At its simplest, to make a double reed the end of a piece of reed or similar plant tube is flattened so its sides nearly touch. Putting this flattened end into the mouth and blowing causes the two sides to briefly close against each other then spring back, hundreds of times a second. This causes a regular stream of air puffs – a squeak.
When this squeaking reed is inserted in the top of a tube, the reed is forced to vibrate at a pitch determined by the length of the tube – the longer the air column, the lower the note – and this is effectively varied by making a series of finger holes.
Squashed-tube reeds are used in some instruments, but more often the reed is made by binding the narrow ends of two thin wedge-shaped pieces of reed, cane, or similar material to a small metal tube (known in English as the staple), which is then inserted into the top of the playing tube.
The global shawm
Members of the shawm family are by far the most numerous and widely played of the double-reed instruments across the globe. Details vary worldwide, but the prime features of a shawm are a double-reed fitted into a conical bored tube that usually ends in a flared bell. A strident sound is also characteristic. The western classical oboe and its orchestral relatives have key systems and a tamed tone, but are nevertheless types of shawm.
Turkey and the surrounding area are shawm heartland, and many other shawms of the world have their origins in the Ottoman Empire. The English name 'shawm' – that of a Renaissance instrument developed from the oriental form – could derive from the Latin calamus, meaning a reed or stalk, or (perhaps more likely since shawms seem to have arrived in Western Europe during the Crusades) from an old Arabic name for a reed instrument, salamiya or salameya, to which the Latin word also appears to be related. Some other instrument appellations are similar, such as the Italian ciaramella, which is characteristically played in duet with a zampogna (bagpipe) and chirimia, a historical instrument in Spain, and a folk shawm still played in Guatemala.
Eastern double-reed instruments
The Ukrainian shawm, introduced from Turkey or the Caucasus and once played by Cossack armies, is called zurna, which is believed to be a modification of the Persian name for the instrument, shahnai (from the Persian words shah and nai, meaning 'king' and 'reed' respectively).
Many other shawms – most of them very similar in design – share that derivation, with spelling or transliteration differences even within the same region: the Indian shehnai, Afghan, Iranian, central Asian, and north African shawms variously spelt sornai, surnai, sorna, and surnay. Greek Thracian zournas, Macedonian zurla, and probably also the Tunisian zokra.
The name of the Chinese shawm, suona, which usually has a metal bell, is in keeping with its Middle Eastern origins. Among the numerous other shawms of East and Southeast Asia are the Vietnamese ken, Korean p'iri, Thai pi, and Tibetan rgyaling. The sound of Egypt's mizmar, whose name derives from mzr, meaning 'to play', is ubiquitous in Egyptian music, although in today's Arabic pop it is usually synthesized on a keyboard.
European and African double-reed instruments
The Moorish invasion of Iberian resulted in the spread of instruments like the shawm. In much of central Spain it is known as the dulzaina. In Valencia as dolçaina, in Catalunya a gralla, and across the French border in Languedoc a graille. In the Basque country in the north, despite that region being less affected by Moorish culture than the rest of Iberia, it is called a gaita – a name that more usually across Europe refers to a bagpipe, but in the Moorish homelands of North Africa ghaita, ghaida, rhaita, or ghaita means a shawm, and it is a common instrument. Close relatives in Niger, Mali, Chad, Cameroon, and Nigeria – on which the wooden playing tube is sometimes covered in leather (rather like a cornett) – incorporate the Arabic definite article 'al' as algaita, alghaita, etc.
A common accompanying instrument for shawms, particularly among itinerant and Roma musicians, is drums. Also typical is support from another shawm, either in unison or providing a drone, as for example in the Karnatic tradition of the south Indian nadaswaram. The other member of the pair is sometimes a bagpipe, as in the Breton pairing of the very shrill bombarde with the bagpipe biniou, in which the bagpipe sustains the tune as the bombarde takes a breath.
Some of the more oboe-like shawms are played in ensembles of different sizes. The sapilla of Istria and the nearby island of Krk on the Adriatic exists in two sizes, both unkeyed, that play intertwining lines. Crucial to the sound of a cobla, the brass and woodwind band playing for sardana dancing in Catalunya, is a pair of oboe-like keyed tibles plus two lower tonoras.
Duduks and related instruments
There is a distinct group of double-reed instruments that, unlike the shawms, have a very seductive mellow, voice-like tone. In appearance they are all quite similar: a cylindrical playing tube with no bell, into which is fitted a very large reed of the squashed-tube variety, fitting directly into the top of the tube with no staple. Slipped over the reed is usually a tuning bridle of rattan.
The best known of these today – largely through the playing of Djivan Gasparyan – is the Armenian duduk. Made of apricot wood, the body has nine finger holes on the front, of which seven are fingered, and a thumb hole at the back. Normally a second player provides a continuous drone, using circular breathing. Close kin of the duduk are the Georgian diduku, Turkish may, Mongolian guan, Chinese kuan or guanzi, and a characteristic instrument of gagaku (Japanese court music), the bamboo hichiriki.