TITLE

ACCESSORY DEVICE FOR PERCUSSION MUSICAL INSTRUMENTS

Technical field

The present invention relates to an accessory device for percussion instruments, in particular for musical drums.

Specifically, the accessory device which is the subject of the present invention is a mechanical acoustic compressor and equaliser for percussion musical instruments.

A percussion instrument, specifically a musical drum, has a cylindrical case or shell, generally of wood or metal, but in the case of certain particular models, also in plexiglass or other materials, closed on both sides by natural or synthetic membranes called skins.

The upper skin on which the musician acts is called the batter skin, while the lower skin is called the resonant skin; both are tensioned by two rings (made of metal or wood), fixed to the shell by screw tie-rods and metal lugs.

On the principal drum in the battery, called the snare drum, there is, below the resonant skin, a snare, i.e. a bundle of cords (generally metal and twisted), which may be put into contact with the membrane, or distanced from it by means of an adjuster device with screw and tie-rods located outside the shell.

The snare has a very precise acoustic function.

The upper and lower membranes are coupled together both by the air enclosed inside the drum, and by the vibrations from the case. The cords are coupled substantially only to the lower membrane, because the vibrations of the case are substantially only radial.

In the case of the snare drum the shell is cylindrical and there is not very much included air. The effect of the air is sufficient to couple the upper and lower membranes together, but the resulting sound is always of indefinite pitch. The drum however produces a wide waveband sound, but rather "round", at least as long as the snare is not used. The upper membrane is excited directly by the percussion, and therefore moves according to a superposition of its normal modes.

The air located inside the drum is compressible, and therefore behaves like a spring with respect to the two membranes (they too being endowed with elasticity); said membranes can be considered in their turn masses connected by springs.

The drum roll is obtained by combining the blow of the drumsticks with the effect of the cords, which are stimulated to vibrate by the lower membrane, and add their dry, shrill character to the succession of blows, as well as an all-waveband background noise.

State of the art

The sound of a musical drum, and in particular of the "snare" drum, is notoriously rich in harmonic and resonant frequencies.

When a drum is struck, the skin vibrates producing, besides the fundamental sound, a wide range of fundamental frequencies and harmonics which sometimes, according to requirements, are undesired; often even annoying. Besides the fundamental frequencies, a wide range of frequencies are produced by way of the vibration of the snare, resting on the lower skin, which characterises it.

These vibrations, generally, must be limited or contained to return a clear and pleasing timbre . A clean sound is always useful, both in the orchestra and when studying the basic exercises of the battery.

Vibrations represent a problem when the sound of the drum has to be amplified at live concerts or at acoustic recordings in the recording studio. In fact, in studio recordings or recordings made at live concerts, the sound of the drum needs to be "clean" and defined according to the taste of the musician, the type of music being performed and the acoustic characteristics of the environment where the performance takes place.

The solutions hitherto adopted for reducing the disadvantages connected with the presence of these undesired frequencies and vibrations are numerous: from the use of a series of mechanical expedients which are nothing but artificial attenuators, made of rudimentary materials (foam rubber, cloth), resting on or glued to the skins, which function as mutes, to the burdensome use of various expensive electrical apparatus, such as sound equalisers, which can filter and attenuate the annoying frequencies or certain harmonic frequencies, and acoustic dynamics compressors.

The presence or otherwise of a snare makes no difference: the problem encountered with the snare drum can also be found in all musical drums, thus also in those without a snare.

Generally, in order to optimise the intervention of electronic devices, it is necessary to isolate the microphones placed around the drums inside a cumbersome "cage" (generally made of plexiglass) in order to avoid acoustic feedback from other instruments. These can give rise to annoying known disturbances such as the "Larsen effect", where a sound is progressively amplified in a closed system.

Object of the invention

An object of the invention is therefore to create an accessory device for percussion musical instruments capable of overcoming the disadvantages encountered in the prior art.

An object of the invention is therefore to create an accessory device for percussion musical instruments capable of functioning as a compressor and simultaneously as an equaliser for musical drums without altering in any way the intrinsic constructional characteristics of the skins and of the drum.

It is an object of the present invention to propose an accessory device for percussion musical instruments capable of attenuating and/or eliminating certain annoying frequencies and/or making them more identifiable and therefore selectable in order to obtain a cleaner sound.

Finally, a further object of the present invention is to propose an accessory device for percussion musical instruments capable of attenuating and/or eliminating certain annoying frequencies simply, rapidly and inexpensively. These and yet other objects are substantially achieved, according to the present invention, by creating an accessory device for percussion musical instruments comprising the characteristics expressed in claim 1 and/or in one or more of the subsequent claims.

Further characteristics and advantages of the present invention will appear more clearly from the detailed description of an accessory device for percussion musical instruments in accordance with the present invention. Brief description of the drawings

This description will be explained below with reference to the attached drawings, provided solely for exemplary and therefore non-limiting purposes, in which:

- figure 1 shows a plan view from above of an accessory device for percussion musical instruments according to the present invention and in accordance with a first embodiment;

- figure 2 shows a sectioned side view of the device illustrated in figure 1 ;

- figure 3 shows a plan view from above of an accessory device for percussion musical instruments according to the present invention and in accordance with a second embodiment;

- figure 4 shows a sectioned side view of the device illustrated in figure 3;

- figure 5 shows an accessory item of the object in accordance with the present invention according to the particular second embodiment illustrated in figure 3;

- figure 6 shows a sectioned side view of the item illustrated in figure 5;

- figure 7 shows an exploded perspective view of the device according to the configuration illustrated in figures 3, 4, 5 and 6;

- figure 8 shows a sectioned side view of the device which is the subject of the present invention in association with a percussion musical instrument.

Detailed description of preferred embodiments of the invention With reference to the aforementioned drawings, no. 1 comprehensively indicates an accessory device for percussion musical instruments T according to the present invention.

This accessory device 1 is a mechanical acoustic compressor and equaliser for percussion musical instruments, in particular for musical drums.

A musical drum comprises a cylindrical case closed by an upper skin, called the batter skin B, and a lower skin, called the resonant skin R, both put in tension by two rings (made of metal or wood), fixed to the shell by screw tie- rods and metal lugs.

The accessory device 1 which is the subject of the present invention comprises a base disc 2, having an upper surface 2a, a lower surface 2b, and a perimetral rim 3 extending in elevation from the upper surface 2a along the entire perimeter of the disc 2.

This device 1 is externally connectable to the bottom of a percussion musical instrument in such a way as to create, between the upper surface 2a and the resonant skin, located on the bottom of the musical instrument, a compression chamber 4 which compresses the air contained therein, limits the vibration of the resonant skin and eliminates annoying frequencies.

Preferably, the musical instrument T, in the case for example of use with snare drums, can simply rest on the perimetral rim 3 of the disc 1 , to which advantageously it can also be secured, or, in the case of application to hanging drums such as tom-toms, it can be removably constrained by special hooks, not illustrated in the attached drawings.

The perimetral rim 3 has a lower edge constrained to the upper surface 2a of the disc 2, and a free upper edge 3a on which is provided a step 5, advantageously equipped with a gasket 6 which improves the coupling between the metal ring which stretches the skin of the drum and the accessory device 1.

The gasket 6 can be made with a thickness in cloth, felt, polymeric material or other material capable of damping any further vibrations which could be produced following the coupling between the device 1 and the musical instrument T.

Preferably the disc 2 is a plate, made of wood or composite material or of malleable synthetic material, having diametral dimensions similar to those of the musical drum T to which it is attached; specifically, the disc 2 has a diameter equal to or slightly larger, preferably by an amount of the order of one or two centimetres, than the diameter of the drum to which it is desired to attach it.

The disc 2 can have a variable thickness comprised between 1 mm and 20 mm, preferably between 2 mm and 15 mm, even more preferably between 2 mm and 10 mm. Depending on the thickness, the disc 2 is more or less rigid: the choice of the optimal thickness depends on the necessary timbres which it is desired to obtain and on the intensity with which the musician normally plays (beats) the drum.

Besides the thickness, the quality and type of material with which the device is constructed represents a variable capable of influencing the final "voice" in terms of timbre. Preferably the disc 2 is made of wood, possibly woods of various type, while the rim 3 may be made of wood or composite materials or inert synthetics such as plastics and resins.

As has been said, between the lower resonant skin of the drum and the upper surface 2a of the disc 2 there is created an acoustic compression chamber 4.

This compression chamber 4 is an air chamber whose volume varies according to the height of the rim 3 on which the drum T rests (figure 8): specifically, the rim 3 has a height comprised between 5 mm and 30 mm, preferably between 10 mm and 20 mm.

There may also be provided, as a further accessory, a second annular rim, not illustrated, complementary to the perimetral rim 3 already fixed to the base of the disc 2, connectable thereto in order to increase as necessary the height of the compression chamber 4, and therefore its volume. This secondary rim has on one side, the one facing the rim 3, a profile in negative of the rim 3, while on the opposite side it has the profile in positive of the rim 3.

In use, the accessory device which is the subject of the present invention is attached externally to the bottom of the musical drum, resting the lower ring which stretches the resonant skin on the step 5 of the perimetral rim 3. In this way a compression chamber 4 is created with the resonant skin R.

The percussion exerted on the batter skin B reverberates on the resonant skin R below, due to the compressibility of the air contained in the drum T. The resonant skin R is thus made to vibrate.

The compression chamber 4 therefore acts as an "acoustic chamber" which presses on the resonant skin R and mechanically compresses the vibration of the resonant skin in a natural manner at each blow, so as to allow a simpler and more accurate search for the desired timbre without the need for excessive electronic controls.

This solution in no way alters the intrinsic constructional characteristics of the drum or of the skin. Its application is not therefore invasive.

The sound of the beaten drum is mechanically compressed by the air of the compression chamber 4: the peaks of some frequencies are attenuated and many frequencies, though present, are restricted.

Consequently, the compression chamber 4 contains the vibrations within itself and, at the same time, exerts a thrust on the resonant skin R, preventing it from vibrating freely.

In this way, spurious frequencies are eliminated and there remain only certain easily identifiable frequencies which the sound technician can decide in the course of the recording process or during a live show whether to leave or eliminate since they are damped, attenuated and selected.

Furthermore, in the particular case of application to a snare drum, the compression chamber 4 enables perfect and complete adherence of the snare over the entire surface of the resonant skin. The air thrusts the snare uniformly onto the surface of the resonant skin, creating an adherence which eliminates the annoying frequencies.

The elasticity of the air in the compression chamber 4, and therefore its action on the skin, depend essentially on factors such as the rigidity of the disc, determined by its thickness and the type of material of which it is composed. The timbre solutions which can be obtained by varying these factors are therefore extremely numerous.

The device 1 can be made in accordance with a second embodiment, illustrated in figures 3 and 4.

According to this alternative solution, the disc 2 has, on its upper surface 2a, in particular in the space contained inside the perimetral rim 3, at least one aperture or slot 7 passing from one side to the other through the thickness of the disc 2.

Preferably, this aperture 7 is at least partially closable.

Advantageously there is a plurality of through apertures 7, all at least partially closable, for the air to escape from the compression chamber 4.

These apertures, or slots, 7 return a frequency response, a more modulated and softer voice, comprised between the natural position (sound of the free drum) and that obtained with the equaliser plate (compressed sound) taking into account the identifying touch, i.e. the intensity with which the musician plays the drum.

The attenuation gradient, i.e. the ratio between the intensity of the blow of the drumstick on the resonant skin and the desired degree of compression and equalisation, can be regulated by these apertures 7, formed on the base of the disc 2; the opening of each aperture 7 can be regulated by an appropriate closure mechanism 10 for said apertures, which is capable of opening them completely or partially to various stages of opening, or closing them completely.

The apertures 7 are distributed over the surface of the disc 2, preferably regularly and at equal spacing from each other. Their shape and size can vary from disc to disc and can be defined on the basis of the sound effect which it is desired to obtain. Preferably, the apertures of a single disc have the same shape.

Advantageously, the total sum of the areas occupied by the apertures is equal at the most to a third of the total area of the disc 2; preferably it is less than a third of the total area of the disc 2.

The closure mechanism 10 for the opening of each aperture 7 comprises at least one panel 8, superimposed on the disc 2, located resting on the upper surface 2a of the disc 2 and slidably movable with respect to the disc 2, to completely or partially open, or completely close, the apertures 7.

The panel 8, concentric with the disc 2, preferably has apertures 8' identical and complementary to those present in the disc 2 and located in the same position with respect to the latter, in such a way that, in a particular angular position of the panel, the apertures 8' in the panel 8 can perfectly line up with and overlie those in the disc 2 to achieve the maximum opening of the compression chamber 4.

By rotating the panel 8 more or less and sliding it over the disc 2, it is possible to partially close the apertures 7 in the disc 2, disaligning the apertures 8' little by little with the apertures 7.

The closure mechanism 10, and in particular the panel 8, can also be made according to different embodiments, but conceptually all be capable of being moved between a plurality of positions which leave the slots 7 completely open or effect a partial or complete closure thereof.

For example, closure mechanism 10 can provide for a plurality of panels arranged wedge fashion and connected to each other, completely full, therefore without slots, which occupy the intermediate position between two successive slots 7 when it is desired to leave them completely open, and are gradually overlapped thereon until they have closed said slots.

The panel 8 is placed in contact with the upper surface 2a of the disc 2 to adhere and respond to the air pressure generated by the blow on the batter skin. The thrust of the air makes the panel 8 "adhere" better during percussion.

The movement of the panel 8 is preferably effected manually by means of a lever or other movement mechanism 9 activatable from outside the device 1. Partial opening to the external environment or complete closure of the compression chamber 4 makes the air imprisoned therein more or less active, and therefore compressive, on the resonant skin of the drum.

The degree of aperture of the slots 7 has the object of regulating, controlling and varying the pressure inside the chamber 4.

The timbre of the drum will vary by degrees, by a significant amount, according to the amount of aperture and compression of the air imprisoned in the compression chamber 4.

In each case the sound is always modified by comparison with that of the drum in the free position.

The device which is the subject of the present invention thus makes it possible to obtain a double effect since it is capable of acting both as a compressor, thus compressing the frequencies, levelling them and avoiding peaks upwards and downwards, softening the "noisier" parts of the percussion instrument so that the dynamic behaviour is a little more predictable and normalised, and as an equaliser since it makes it possible to emphasise or attenuate certain frequencies in particular, making them, in each case, easily identifiable and selectable.

The device acts therefore as a mechanical acoustic compressor and equaliser without the need for complicated electronic instrumentation but simply by means of mechanical compression of the vibration of the resonant skin in a natural manner, so as to allow a simpler and more accurate search for the desired timbre without the need for excessive electronic controls.

Furthermore, the device which is the subject of the present invention is capable of modulating certain parameters by which the sound response of the musical instrument is measured, such as for example attack, fade and sustaining times and/or other qualitative parameters such as voice and resonance.

The device which is the subject of the present invention is inexpensive, noninvasive, adaptable to any currently commercial or proprietary instrument and easy to use.

In the configuration equipped with slots, it permits a certain degree of adjustment of the compression by means of moving the panel and therefore partial opening of the slots, making it possible to vary the acoustic effect obtainable.