Membranophone

Membranophone (Latin - Greek coinage, " fur Klinger " ) refers to a musical instrument that has a diaphragm to create sound. This membrane may be a stretched animal skin, including parchment, plastic film, paper or the like. So that the sound membrane, it must be made ​​to vibrate. This is usually done by hitting as the beater drum. There is also grater drums, the membrane is coated with a subject, and known as Ektara in India plucks drums. When Kazoo and Mirliton the membrane is caused by blowing into vibration. All kinds of drums are among the membranophones.

Depending on the design of the Membranophone produced when striking a sound with an audible tone or a more diffuse mixture of different frequencies. Among the highly perceivable tonal instruments include the timpani, the Boo - bam and the tabla. Boo - bam and Tabla Tarang can be used because of their many individual instruments for the melodic structure.

Physics

The physical principles of sound development in membranophones are well known. However, in the specific case, it is extremely difficult to describe the various physical effects so that it could be used to describe the proportion of the sound shaping. At least there are some similarities between the behavior of electrodynamic loudspeakers and membranophones.

For simplicity, the word drum is used in the following explanations apply but for all types of membranophones.

The body has - as the housing the speaker - a major influence on the sound of the membrane, but in both cases no active function. Even if the body resonates, that radiates sound, this is so much quieter that it is not recognizable as sound source over the batter head mostly. The body works from a physical standpoint as an attenuator, ie " sound shaping ". Frequencies are attenuated mainly by the kinetic energy goes in part to the body. Some frequencies are amplified by resonance between the membrane system and air volume of the body.

The suspension of the diaphragm makes up the essential difference between speakers and membranophones. While the speaker cone is centered by a bead and otherwise can swing freely, the drum membrane is clamped firmly on the edge of the body. With this suspension gives rise to various vibrations of the membrane, radial, and concentric partiale. They are - in contrast to the speaker - in eardrums quite desirable as they contribute to shaping sounds. In drumheads one takes effect on these vibration characteristics - and thus on the overtone spectrum - through various thicknesses of the material, coatings, ply constructions as well as by additional bonded cushion rings or spots.

Membranophones can be divided into four categories:

• Frame drums (Example Roto - Tom, Tambourine )
• Tube drums, open at the bottom ( eg " Concert Tom," Octoban )
• Boiler drums ( timpani example )
• Tube drums, but the bottom closed by a resonant head (example: drums on drums )

The sound of a drum with or without an open base frame is determined by the acoustic short circuit. The larger the corpus, the fuller sounds the drum. This drum variant with a single coat also has a defined fundamental lack of interference.

The boiler drum also has a relatively clear root, but the boiler requires a large volume in order to achieve a proper sound volume. The closed drum behaves physically similar to a closed speaker box.

The drum resonant head uses basically similar physical effects such as the bass reflex box, here's a deeper tone is amplified by resonance, the body can still remain relatively small. The enclosed volume of air in the drum acts as a physical mass-spring element. The acoustic short circuit is also effective, comparable to the behavior of a bass reflex box frequencies are strongly attenuated below the resonance frequency.

An elaborate analysis of the vibration characteristics of membranes was carried out on the example of the timpani.