A membranophone, in the Hornbostel-Sachs classification system, is an instrument that produces sound through the vibrations of a membrane. Membranophones, in some form, have existed for more than 4,000 years. Usually a membranophone is a drum which makes a sound when the membrane is hit by hands or sticks. Some drums can be set to different pitches by tightening or loosing the tension on the skin.

 

There are four basic types of drums:

 

Frame drums, in which one or two membranes are stretched over a frame such as the tambourine or bass drum.

Friction drums, in which the membrane vibrates when a string is pulled through it, the membrane is not struck.

Vessel drums, in which a membrane is stretched across a vessel such as the kettledrum.

Tubular drums, in which a membrane is stretched over one or both ends of a tubular form. Tubular drums are often classified by the shape of their body:

 

    · Barrel: a drum with bulging sides such as the conga.
    · Conical: a drum whose head is larger than its base.
    · Cylindrical: a drum with a long, narrow body and straight, even sides, like the timbales.
    · Waisted: a drum that is narrower in the center than at both ends.
    · Goblet: a drum that stands on a narrow base.
    · Footed: a drum with feet carved from its body.
    · Long: a drum whose length significantly exceeds its diameter.

Kazoos are also considered among the membranophones because the sounds they generate are the result of a vibrating membrane stretched. This places in a class of instruments known as mirlitons.