1. Field
The present invention finds its application in the technical field of the musical instruments and particularly relates to a percussion musical instrument.
2. Brief Description
As is known, the percussion musical instruments are essentially constituted by a hollow body defining the resonance chamber and having an upper opening closed by a suitably stretched membrane, made of leather or other natural or synthetic fiber, forming the striking surface.
An example of a percussion instrument is the darbuka, formed by a sound box having the form of a double opposing cones with a narrowing middle portion and an enlarged upper opening which the percussion membrane is fixed to.
The sound box may be made of natural materials, for example wood or clay as for the traditional instruments, or metals and metal alloys, for example aluminum and its alloys, in the case of modern instruments.
To allow the fixing of the membrane, the upper edge of the sound box is step-shaped so as to define a seat for housing a locking ring to be screwed to the sound box.
The anchoring of the ring to the sound box is provided by means of a plurality of through screws that pass through-holes made both at the outer ring and at the inner circular edge of the sound box.
It is also known in popular music culture to use water inside musical instruments in order to obtain a modification of the sound depending on the quantity of water and of the movement thereof inside the instrument.
These instruments, an example of which is the udu, are generally constituted by vessels or other containers in a material suitable for contact with water, for example earthenware, clay or other ceramic materials, designed to be stuck directly on the walls and that have no striking membranes of leather or other elastic material.
On the contrary, the known percussion instruments with membrane made of leather or other material, even synthetic, defining the striking surface, do not allow the use with water or other liquids thereinto, in order to modulate the sound by varying the level of liquid, as the own elasticity of the percussion surface necessarily would cause leakage as a result of vibrations.
For example, in the case of the darbouka described above, usually played with the striking surface facing down, the water would be in contact with the fixing screws of the ring, leaking through the threads.
Moreover, the materials typically used for the sound box are not suitable for contact with water and liquids in general and with time would deteriorate.
A further drawback of the known instruments is represented by the fact that their sound boxes are formed by several parts assembled together, so that in correspondence of the junction lines there are discontinuity lines that cause sound distortion.
U.S. Pat. No. 2,386,211 discloses a closure for metal drums which requires the application of a ring folded in such a way as to have a tight seal of the edge. The drum has a metallic percussion surface applied to the sound box in a fixed manner by welding. Such a system is not suitable to drums provided with flexible striking surface, i.e. in natural or synthetic leather, as it damages the same and would also not allow the correct tensioning.
However, besides this drum does not have a membrane but a metal surface, the type of tight sealing (which requires the welding of the folded edges) is not adapted to be applied to drums with membrane.