Girl With A Musical Instrument

- Aerophones, produce a sound by with a vibrating column of air; they are sorted into free aerophones such as a bullroarer or whip, which moves freely through the air, flutes, which cause the air to pass over a sharp edge, reed instruments, which use a vibrating reed, and lip-vibrated aerophones such as trumpets, for which the lips themselves function as vibrating reeds.
Sachs later added a fifth category, electrophones, such as theremins, which produce sound by electronic means. Within each category are many subgroups. The system has been criticised and revised over the years, but remains widely used by ethnomusicologists and organologists.
• Schaeffner
Andre Schaeffner, a curator at the Musée de l'Homme, disagreed with the Hornbostel-Sachs system and developed his own system in 1932. Schaeffner believed that the pure physics of a musical instrument, rather than its specific construction or playing method, should always determine its classification. (Hornbostel-Sachs, for example, divide aerophones on the basis of sound production, but membranophones on the basis of the shape of the instrument). His system divided instruments into two categories: instruments with solid, vibrating bodies and instruments containing vibrating air.