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"Method and device for converting sounds into colours or colour
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The present invention relates to a method and device for displaying sounds, particularly musical sounds, by means of colours or colour patterns. In other words, the present invention relates to a method and device for transcoding (converting) sounds into colours or colour patterns.
Various attempts have been made to make music visible. These attempts have also been made with the primary aim of enabling persons without hearing to "see" and appreciate music.
The first known attempt to make music visible was that of Isaac
Newton, who sought a connection between optical and acoustic phenomena. He understood that there could be a direct
correspondence between the seven colours of the rainbow and the seven notes of the musical scale. The frequencies of the colours making up the visible light spectrum are harmonically connected to each other in the same way as the notes of a piano. Specifically, they are arranged in a natural scale, called the diatonic scale.
At the end of the eighteenth century, the German physicist Chladni discovered a method for displaying patterns and vibratory paths of sand grains. The so-called "Chladni patterns" appear as a waveform when sand is sprinkled uniformly over a glass panel made to vibrate by a violin bow.
The Chladni apparatus is only one of many different devices which have been constructed and presented over the years by physicists and musicians to enable man to realize the dream of displaying music and achieving a superior emotional experience to add to that provided by the conventional hearing of a piece of music.
Recently, owing to the development of electronic technologies, software programs have been devised for converting musical notes into colours. However, these programs, while theoretically achieving the general aim of displaying music, usually consist of a simple direct and linear conversion of the music, and therefore provide a "cold" and predictable representation of the said music, which is not considered to be capable of giving rise to emotion.
The present invention also has the object of converting acoustic sequences, particularly musical sounds, into colours or colour patterns. However, the present invention makes use of a principle which differs from those adopted in the past, and which makes it possible to obtain spectacular and unexpected representations of musical sounds. These representations are synchronized with the sound field which stimulates them, and can produce fascinating synaesthetic effects on the emotional level.
The present invention comprises a method according to Claim 1 , a device according to Claim 10, a storage medium according to Claim 19 and a computer program according to Claim 21. Further advantageous characteristics of the invention are stated in the corresponding dependent claims. All the claims constitute an integral part of the present description.
The present invention is based on the use of a member which at least partially reflects light and has a variable thickness. The thickness of the at least partially reflective member is varied by the acoustic pressure of the sounds emitted by at least one sound source, located in the proximity of or in acoustic contact with the member. In all cases, the variable thickness member is caused to vibrate by the music and the consequent variation of the thickness of the member, which is illuminated by a light source, produces colour patterns in a dynamic way.
According to a first aspect, the present invention provides a method for converting sounds into colours or colour combinations, comprising the steps of:
providing at least one source of sounds to be transcoded;
providing an at least partially reflecting member having a thickness; varying the thickness of the at least partially light-reflecting member by means of an acoustic pressure of the said sounds, and directing light against the said variable thickness member.
Conveniently, the step of providing an at least partially light-reflecting member comprises the step of providing a film with variable thickness, preferably a film of a surface active solution.
Preferably, the surface active solution comprises glycerine and/or triethanolamine.
Preferably, the images created by means of the light reflected by the at least partially reflective member are recorded on a storage medium. In a second aspect, the present invention provides a device for transcoding (converting) sounds into colours or colour combinations, characterized in that it comprises: at least one source of sounds to be transcoded, and an at least partially light-reflecting member having a thickness, in which the thickness of the at least partially light-reflecting member is varied by means of an acoustic pressure of the said sounds and light is directed against the said variable thickness member.
The present invention will be made completely clear by the following description, provided by way of example and without restrictive intent, to be read with reference to the attached figures, in which:
- Fig. 1 is a schematic lateral view of an embodiment of the device according to the present invention;
- Fig. 2 is a plan view from above of the device of Fig. 1 ; and
- Fig. 3 is a view of the image display screen of Fig. 1.
Fig. 1 shows schematically an embodiment of the device according to the present invention. The device 1 comprises a light source 2 which produces a light beam 3, a lens 4 for suitably collimating the light beam

3, an at least partially light-reflecting member 5 with a thickness which is preferably variable, and a sound diffuser 6. Conveniently, the sound diffuser 6 is connected to a source of sound 7, such as a hi-fi system, a reader of magnetic and/or optical media, or the like. In the embodiment of Fig. 1 , the device also comprises a screen 8.
Conveniently, the light source 2, the lens 4 and the variable thickness member 5 are supported by supports 9, 10 and 11 respectively. The screen 8 is also conveniently supported by a support 12. Finally, the sound diffuser 6 is also held by a support 13 which if necessary can be connected to (or can be an integral part of) the support 11 of the variable thickness member.
The light source 2 can be any light source capable of producing sufficiently intense and white light. Purely by way of example, it is possible to use a lamp with a power of approximately 200 W to produce white light at approximately 6000 Kelvin. In a device 1 according to an experimental embodiment of the invention, a lamp of an ordinary slide projector, readily available on the market, was used.
Thus, according to the invention, what is provided is an optical system comprising a positive lens 4 for collimating the light 3 leaving the source 2, and uniformly illuminating the central part of the variable thickness member 5.
The light beam 3a leaving the collimating lens 4 strikes the variable thickness member 5. The member 5 is a substantially elastic member, at least partially light-reflecting, of variable thickness. Advantageously, the member 5 comprises a film (or membrane) of a surface active solution (such as soap) or the like.
The member 5, or film of surface active solution, is mounted on the at least partially rigid support 11. The support 11 for the member 5 can be made, for example, from a plastics material, and comprises an aperture 110. Conveniently, the aperture 110 has a substantially circular shape, but other shapes, for example oval, rectangular (particularly with the sides in the ratio defined by the golden section) or triangular, can be used according to the present invention. Conveniently, the membrane support 11 comprises a concave body 111 , which may be substantially hemispherical if necessary, closed by a wall 112. The aperture 1 10 is provided in the wall 112. The internal surface of the body 111 is conveniently blackened to eliminate any possible reflections.
The sound diffuser 6 comprises an acoustic transducer based on a piezoelectric effect. According to the invention, the sound diffuser 6 is in acoustic contact with the member or membrane 5. In other words, according to the invention, the sound diffuser 6 is in direct physical contact with the membrane 5 or is placed at a suitable distance in such a way as to create acoustic impedances' and impedance matching. This is because, according to the present invention, one of the most important factors affecting the variation of the thickness of the film 5 is the acoustic pressure of the sounds emitted by the diffuser 6. For the purposes of the present patent application, the term "acoustic pressure" denotes at least one of the intensity, frequency and timbre of the sounds emitted by the said diffuser.
The sound diffuser can be a loudspeaker and is connected to a source of sound, for example a hi-fi system, a reader of magnetic and/or optical media (discs, tapes, CD-ROMs, DVDs), a musical instrument, a plurality of musical instruments (musical groups, orchestras, bands) or the voice of one or more singers or speakers. In the embodiment of Figs. 1 and 2, the light at least partially reflected by the membrane or film 5 is conveniently projected on to the display screen 8 in a display area 14. The images 15 created on the screen 8 can be recorded, if required, on a storage medium (not shown) and displayed in places other than the place in which these images were originated. Conveniently, the corresponding sounds which gave rise to these images can also be simultaneously recorded on the same storage medium (which can be of any type, for example magnetic or optical) as that on which the images are recorded. Thus, for example, the colours or colour patterns produced by transcoding a piece of music transcoded by a device according to the invention could be seen by more than one person in different places.
The membrane 5 can be positioned with any inclination with respect to the horizontal plane. In Figures 1 ,.2 and 4 it is vertical, and the images 16 produced in the display area 14 are substantially
symmetrical about an axis of symmetry 15. If the membrane 5 is positioned horizontally, the images 16 will be symmetrical about a vertical axis passing through the centre of the membrane (if it is circular).
The vibration of a circular membrane of surface active solution can be described by the following equation of motion (1 ), in which the plane x-y is the plane in which the membrane lies and z is the direction of excitation of the said membrane.
d2z/dx2 + d2z /dy2 = (Uc)2dzz/dt2 (1 )
The constant c in equation (1) is measured in units of velocity (for example m/s) and c2 = γ/p, where y is the surface tension and p is the surface area density, a constant given by p = m/A, where m is the mass and A is the area of a membrane of surface active solution. The general solution of equation (1) can be written thus:
z = W(x,y) exp(iγt) (2)
This provides the normal modes of vibration of the membrane: the vibrations take place with a constant frequency y in the direction z.
Additionally, W(x,y) depends on the conditions at the profile set for the membrane.
When the membrane 5 is not excited by acoustic pressure and is in a vertical position, its thickness or profile increases gradually in the downward direction. Naturally, the thickness of the membrane and its vibratory behaviour are also affected by other characteristics and factors. These include the dimensions of the aperture 110, its shape, the fluid dynamic characteristics of the surface active solution, the geometry and the nature of the support 11. The environmental conditions (humidity, temperature, presence of atmospheric
precipitation, wind, etc.) to which the device is exposed also modify the response of the membrane.
The sound pressure transferred to the membrane causes vibrations and movements of liquid in the said membrane. The incident white light is reflected by the membrane. The interference between the rays reflected by the outer surface of the membrane and those reflected by its inner surface produce colour patterns which change in a dynamic' way. When the membrane becomes resonant, the material of the membrane is put into motion and highly spectacular effects are produced.
The vibratory movements of the membrane in resonant conditions can reach dimensions of the order of a millimetre, while the thickness of the membrane, of the order of the wavelength of visible light, is considerably smaller.
A device 1 according to the present invention was constructed for experimental purposes. In the experimental embodiment of the device 1 , an ordinary slide projector was used as the light source 2, and a positive lens 4, with a diameter of 3 cm and a focal length of 12 cm, was placed between the projector and a surface active membrane to
- collimate the light and provide uniform illumination of the central part of the membrane. The inventors found that the flat surface active membrane, positioned vertically and illuminated by the collimated white light, operated substantially in the same way as a mirror. The reflected light was projected on to a screen by means of a flat-convex lens with a diameter of 10 cm and a focal length of 30 cm, in such a way as to optimize the clearness of the image of the membrane on the screen. In the experimental device, the membrane was attached to the circular aperture of a hemispherical cover of a plastic desiccator having a diameter of 14 cm. As is known, a desiccator is a device (generally made from plastics or glass) used in chemistry to dry chemical substances at a reduced pressure. A ring with a diameter slightly greater than that of the circular aperture of the desiccator was used to place the surface active solution in position. A small loudspeaker was mounted on the desiccator to act as the sound diffuser.
The frequency response of the loudspeaker used in the experimental system covered the range from 70 to 6400 Hz, with an impedance of 16 Ω, a sensitivity of 85 dB and a maximum power of 0.2 W.
The interior of the desiccator was painted black to eliminate internal reflections. To change the curvature of the membrane for particular purposes, the support (desiccator) was provided with means for regulating the air pressure in the cavity between the membrane and the loudspeaker.
A ring with a diameter slightly greater than the said support was used to apply the surface active film to the edge of the support. In the experimental system, the ring was made from a tube with a wall thickness of 6 mm. The edge was carefully wetted with a cotton swab impregnated with surface active solution before the membrane was applied. To deposit the membrane, the ring with the surface active solution was carefully moved until it was parallel with the edge of the membrane support. The membrane support was fixed to a rotatable support which could be rotated to bring the membrane into a vertical, or at least an inclined, position.
To provide the surface active membrane with sufficient durability for a certain number of cycles, it was essential to select a surface active solution having the correct composition. Good results were achieved with a solution containing approximately 1.4 g of triethanolamine which was reacted chemically with 2.0 g of oleic acid and then dissolved in 100 g of glycerine. It was found statistically that a circular membrane with a diameter of approximately 10 cm produced by this solution could last for more than half an hour without any need for special protective measures.
A flat surface active membrane fixed vertically has a thickness which is substantially trapezoidal in shape and becomes gradually thicker towards the bottom of the said membrane. Immediately after the formation of a new film, the liquid solution slides towards the lower part, mainly under the effect of gravity. In all cases, a state of equilibrium is soon reached. The thickness of the membrane, measured at any . height, is theoretically identical.
In the unstressed state of the membrane, streaks of spectral colours appeared on it whenever there was constructive interference between the incident light reflected by the front surface and that reflected by the rear surface. In other cases, the membrane was not coloured, and no coloured streaks were visible.
The relationship between the particular incident wavelength of light and the thickness of the membrane determined whether the
interference was constructive or destructive.
In particular, it was found that, conveniently, there was no decrease in the thickness of the membrane when a glycerine-based surface active solution with a composition as described above was used. This was due to the absence of evaporation. Another benefit provided by the use of a surface active solution as described above is the absence of turbulence. Consequently, this type of membrane proved to be highly stable immediately after its formation, showing a sequence of stationary horizontal streaks or spectral colours.
On the other hand, when the membrane was excited, for example by the impact of sounds, its thickness changed, creating movements of liquid in the said membrane. Colour variations were observed as a result.
To summarize, the present invention is based on the use of a surface active membrane (of soap for example), through which an intense beam of white light is passed, and a microphone (or other sound diffuser) which transfers the instantaneous pressure p(t) of the music, the diffuser being placed in acoustic contact on the support of the said membrane. The acoustic stress changes the thickness of the
membrane, substantially in real time. The membrane acts as an interference filter. Thus, the spectral colours are selected and are closely correlated, although in a linear way, with the frequency, intensity and timbre of the sounds responsible for the variation of thickness, and these colours tend to take on unusual shapes which are also closely correlated with the music which activates the membrane. Conveniently, the image produced by the performance of a piece of music is projected on a screen and is acquired by cinematographic recording from the screen. The chaotic bursts of colour caused by musical passages of greater intensity and drama are particularly impressive and even unforgettable.
The present invention provides an impressive display of musical sounds and pieces as originally predicted in the days of Newton. The proposed technology makes use of a fluid dynamic system (a surface active membrane) which is highly sensitive and rapidly responsive to acoustic pressure.
The present invention is suitable for many different applications. In the first place, it is proposed as an alternative to conventional music for people with impaired hearing or with no hearing at all. This is because such people could appreciate music (when it is displayed) even though they cannot hear it.
The present invention proposes the recording of the images produced by the performance of a piece of music or the like on a recording medium (for example a disc), together with the corresponding piece of music if required (on a digital audio-video disc, for example).

The present invention makes it possible to create "ecological" psychedelic effects in places of entertainment (for example
discotheques, dance halls, theatres, amphitheatres, pubs, bars, disco bars), in which it would be possible and pleasant to reduce the intensity of sounds which are frequently deafening and therefore dangerous for the hearing, while still arousing the same emotions. It is even
considered that the images produced by means of the present invention enrich the spectacle provided by concerts of classical or modern music, by using the synaesthetic effect of the non-linear combination of sound and colour.
The images produced by means of the present invention can be a useful educational aid in the teaching of music in schools and academies.
The present invention can be modified in various ways. All modifications, adaptations, variations and replacements of parts with other functionally equivalent parts are to be considered as lying within the scope of protection of the present invention. The possible modifications which can be made include the following.
It is advantageous to use a digital camera as an alternative to an analogue camera for recording the images produced by means of the device and method according to the invention. Among other
advantages, this will make it possible to filter and eliminate, by means of a suitable software program, chromatic components associated with the membrane's resonant frequencies (interference fringes). Since the process of filtering or eliminating these fringes is a slow process, it is preferable to carry it out on a recording rather than during a live performance.
Although the light source used (that of an ordinary slide projector, for example) is adequate, better results can be obtained by the use of a light source which supplies whiter light.
Although the device described in detail above uses only one sound diffuser to activate a single membrane, it is also possible to use two or more membranes in parallel, the membranes possibly having different sizes, in order to obtain different chromatic effects which, in some ways, are even more spectacular. Each membrane can oscillate in a specific frequency range. If more than one diffuser is used, their location is also important.
Although the geometrical shape of the membrane is conveniently circular, other shapes can be used according to the present invention, for example oval, rectangular (particularly with the sides in the ratio defined by the Golden Section), triangular, regularly polygonal, etc.