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Classification and Pitch of Musical Instruments

Musical instruments are classified by the way they produce sound. Since sound is the result of vibration, the three main categories of instruments are distinguished by how they are made to vibrate. They are percussion, string, and wind. Percussion instruments make sound when force, such as hitting, shaking, or rubbing, causes vibration. Strings on a string instrument vibrate when they are plucked. The tubular shape of wind instruments holds a column of air that vibrates when it is stirred by wind, in the form of breath.

By far the most common, percussion instruments include drums, a vital part of communication between Halls and Holds, as well as bells and rattles. String instruments, such as gitars and lap harps, are often used by Harpers to entertain and teach others. Flutes and pipes are popular wind instruments, but rare metal bugles and trumpets kept at the Harper Hall are also part of this instrument family.

The vibration of percussion instruments occurs in one of two different ways. Either a membrane or a solid piece of material will vibrate, such as in the case of drums or bells, respectively. The pitch of a drum depends on the thickness and tension of the leather drumhead, while the pitch of a bell depends on how much material is vibrating, i.e. how big it is. Therefore, the sound of a drum can be altered by changing the leather weight or tension in the drumhead, whereas a separate bell is needed for every different pitch required.

Fast vibration in string instruments results in higher pitch, slow vibration in lower pitch. The pitch can be changed by altering the length, thickness, tension, and density of the strings. Short, thin, tight, and lightweight strings will create faster vibration than long, thick, loose, and heavy strings. Changing the vibrating length of the string, either by having strings of differing length or by using frets to foreshorten the vibrations, allows for a variety of pitches on one string instrument.

The column of air inside wind instruments is made to vibrate, and thus produce sound, by blowing across an edge, forcing some air across and some inside the opening. Pitch depends on the volume of air that is vibrating with higher pitches requiring a smaller volume of air due to the faster vibration that is produced. Single-tube wind instruments usually have holes along the instrument's length that allow the player to change the pitch by covering them and, therefore, increasing the volume of air. Multi-tube wind instruments generally do not have holes; instead, the tubes are of distinct, descending length, raising the pitch by reducing the volume of air in each one.

While only three types of instruments may seem limiting, these are just the main categories. Numerous instruments with widely varied shapes and sounds are found in each and provide their own unique challenges to instrument makers and players alike. Played alone or with accompaniment, musical instruments are a skillful method of communication, a vital aid in training, and a beautiful means of evoking emotion.

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Written by Journeywoman Lysa, SouCon MUSH