Musical Instruments Critic Blog

The Four Classes Of Musical Instruments

March 29th, 2007 Subscribe To Our Feed

The musical instruments had a big influence over the human evolution over time, they appeared long before writing or any other cultural element. At first, instrument sounds were used primarily for communication between people and later they evolved in an act of cultural or religious ceremonial. Nowadays, the classification need characteristic to our society led to a study of the musical instruments, and this curiosity resulted in what we know as the four classes of musical instruments.

The first in the four classes of musical instruments are the chordophones that produce sounds by using one or several vibrating strings. It is in this category that many include the well known guitars, harps and violins. But when it comes to the musical bow or the piano, also called a keyboard or percussion instrument, musicians are more reluctant to include them here. The chordophones can be divided in two primary groups: the ones that have a resonator, and the ones without the resonator. Unlike the guitar and the violin the piano can be played even without the resonating casing.

The second group of the four classes of musical instruments are the aerophones, consisting of any instrument that produces sounds by vibrating a mass of air without the using strings or membranes. The most important feature is that the instrument doesn’t have to vibrate by itself. The bullroarer is an aerophone instrument that doesn’t contain the air inside, another example is represented by the wind instruments like the sirens that appeared on the medieval ships. The musical instruments that contain the air inside are more widely known: trumpets, flutes and oboes.

Next category from the four classes of musical instruments are the idiophones, which are percussion musical instruments. They don’t use any vibrant material such as string or membrane, the instruments vibrate by themselves. There are four sub-groups in this class, the struck idiophones (the marimba, wood block, singing bowl or triangle) they vibrate when being hit with the hand or a stick.

The other forms are very rare: they can be plucked idiophones (the Jew harp), blow idiophones extremely rare, the Aeolsklavier is a good example here, and the last: friction idiophones like the singing bowl or the glass harmonica. The concept of the four classes of musical instruments are based on the original Hornbostel-Sachs scheme and include as a last category all electronic tone synthesizers, vacuum tubes that produce tones by using transistors.