Huene, and Wenner. French maker Philippe Bolton created an electroacoustic recorder and is among the last to offer mounted bell-keys and double bell-keys for both tenor and alto recorders. Those bell-keys extend easily the range of the instrument to more than three octaves. Invented by Carl Dolmetsch in 1957, he first used the bell-key system publicly in 1958. Use in schools In the twentieth century, Carl Orff used the recorder as part of his Orff-Schulwerk didactic approach. His five-volume Musik für Kinder, published between 1950 and 1954, contains pieces for recorders, often in combination with other instruments. Manufacturers have made recorders out of bakelite and other more modern plastics; they are thus easy to produce, hence inexpensive. Because of this, recorders are popular in schools, as they are one of the cheapest instruments to buy in bulk. They are also relatively easy to play at a basic level because sound production needs only breath, and pitch is primarily determined by fingering (though excessive breath pressure will tend to drive the pitch sharp). Recorder ensembles The recorder is a very social instrument. Many recorder players participate in large groups or in one-to-a-part chamber groups, and there is a wide variety of music for such groupings including many modern works. Groups of different sized instruments help to compensate for the limited note range of the individual instruments. Four part arrangements with a soprano, alto, tenor and bass part played on the corresponding recorders are common, although more complex arrangements with multiple parts for each instrument and parts for lower and higher instruments may also be regularly encountered. See also List of recorder music List of recorder players References Bibliography (e-book). External links Recorder Home Page A comprehensive website devoted to the recorder, from Nicholas Lander. How the recorder works Interactive Sheet Music for the Recorder Philippe Bolton's page of Historical recorder fingering charts Philippe Bolton's page of modern recorder fingering charts Recorder fingerings, Charts and trill charts, recorder-fingerings.com Recorder fingerings, Dolmetsch Online Recorder fingerings, Moeck Recorder fingerings, Mollenhauer Recorder fingerings, Woodwind fingering guide Recorder Bibliography, An interactive Zotero bibliographic database compiled by Nicholas Lander that contains details of some 4,000 references concerning the recorder. Baroque instruments Early musical instruments Renaissance instruments Internal fipple flutes