Classification of Musical Instruments

The international classification of instruments was in 1914 prepared by Austrian scientists Curt Sachs and Eduard Hornbostel in order to provide a system for the instruments of the peoples of the world according to their sound creating principle.
That classification has four groups: aerophones (wind instruments), cordophones (stringed instruments), idiophones (that produce their sound from the body of the instrument itself) and membranophones (instruments with a vibrating membrane). Proceeding from this both wind instruments and instruments with bellows belong to the same group (aerophones) because the sound isi n both cases created by the air moving in the instrument. However, as diatonic accordions are, in Estonian cultural landscape, a wide-spread instrument type, we devote a separaate chapter on them in our present publication.
There are two groups of rhythm instruments widely known in the world: one is primarily made up by drums (membranophones) and the other comprises very different instruments that vibrate with their full body of the instrument (idiophones). Some of the idiophones allow playing a melody to some extent, e.g. clappers or the Jew's harp emitting harmonic tones.

Estonian ethnomusicologist Herbert Tampere (1909–1975) categorised musical instruments according to their function into two main groups:

- traditional instruments – instruments created by the folk, and instruments of professional origin that people use traditionally while developing them spontaneously (e.g. kannel, bagpipe, mouth harp);

- popular instruments – instruments of professional music that have entered folk tradition, that is factory productions not evolved the people (e.g. violin, quitar).

Since the person involved in folk music does not generally draw a strict line between the terms mentioned above, the present publication applies a common term "folk instrument".