This invention relates to visual methods of representing sound involving colour. Attempts have been made to translate sound into visual displays of changing colour patterns. In some cases a relationship has been established between sound waves and light waves. However the available apparatus has not been well received owing to the poor fidelity of visual representation of the sound. It is an object of this invention to provide a high fidelity representation of sound by colour. In one form the method of this invention consists in dividing the colour spectrum into twelve hues and correlating each of the twelve notes of the musical octave with each hue in such a way that degrees of consonance and dissonance between notes correlate with that between the corresponding colours with a high degree of fidelity. A further refinement of this method is to represent ascending octaves of colours so correlated by ascending colour value so that the higher octaves are represented by pastel colours and the lower octaves by dark (i.e. low value) colours. Yet a further refinement of the method is to represent sounds corresponding to the superposition of a number of notes by the admixture of the colours corresponding to those notes. A refinement of the method when applied to a dynamic visual colour display is to represent an increase in intensity of the sound by an increase in the area of the colour of the display.

Following is an elaboration of the method with a

reference to the accompanying diagrams in which: Figure 1 is a colour circle showing a preferred correlation between the natural spectral order and the cycle of 5ths of the musical octave. Figure 2 is a colour circle showing another correlation between the natural spectral order and the cycle of 5ths of the musical octave.

Figure 3 is a keyboard showing the correlation of Figure 1. Figure 4 is a keyboard _. showing the correlation of Figure 2. In Figure 1 C is represented by a solid yellow, G by solid yellow and fifty percent magenta, D by solid yellow and solid magenta, A by fifty percent yellow and solid magenta, E by solid magenta, B by fifty percent cyan and solid magenta, F sharp, G flat by solid cyan and solid magenta, C sharp, D flat by solid cyan and fifty percent magenta, G sharp, A flat by solid cyan, D sharp, E flat by fifty percent yellow and solid cyan, A sharp, D flat by solid yellow and solid cyan, and F by solid yellow and fifty percent cyan. In Figure 2 C is represented by solid cyan and solid magenta and the other colours are correlated with the other notes in an order opposite to that of Figure 1. In fact the starting point of correlating the note C is quite arbitrary and the method encompasses all possible correlations between the order of notes shown, in both Figures 1 and 2, and the order of the hues of the natural colour spectrum.

Figures 3 and 4 show the correlated colours of

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Figures 1 and 2 respectively, set out on keyboards. They also illustrate another aspect of the invention, viz. ascending octaves of colour are represented by ascending colour value. The lower octaves on the left of the keyboards are marked with the colours of Figures 1 and 2 which are deep colours, while those on the right are marked with pastel colours which have had white added. Three octaves only are shown in Figures 3 and 4 but the method can be applied to the whole piano keyboard so that the lowest octave is represented by extremely dark colours and the highest octave by extremely light colours.

Whereas individual notes are represented by the particular colours shown, a number of notes sounded at the same time are represented by a mixture of those colours. A unique aspect of the method of the invention is that in nearly all cases the mixture of colours corresponding to consonant notes results in another pure colour whereas the mixture of colours corresponding to dissonant notes results in a murky or grey colour. Hence the colours represent the sounds with high fidelity which is not achieved in the various arbitrary correlations of sound and colour used previously.

A preferred application of the method resides in displaying sound on a dynamic visual display such as a colour television screen. Here the intensity of different notes is indicated by the area of the screen occupied by the colour corresponding to those notes. Various ways of

achieving this result are feasible. Such as by:-

(a) A uni-directional vertical expansion of a horizontal bar upon a portion of the screen.

(b) A bi-directional vertical expansion of a horizontal bar.

(G) From a single point bi-directional both horizontal and vertical expansion.

(d) A plurality of expanding colour displays referred to in (a) to (c) above in individually assigned areas on the screen.

(e) Concentrically arranged areas assigned to respective hues having both vertical and horizontal expansion and capable of overlapping.

The method of this invention also has other applica- tions. It may be used in the teaching of musical instruments By afixing correlated colours to keys or positions on a guitar stock for example, and annotating the musical score in the same manner, students have an immediate visual guide to their playing which is not mediated by the naming of the musical notes. Although this method of teaching musical instruments is already known for quite arbitrary colour correlations, the unique correlations of the method of this invention are much more effective. This and other applications are possible which embody the basic method of this invention.

OMPI