METHOD OF AND APPARATUS FOR REALISING SPATIAL SOUND EFFECTS

Abstract: A method and apparatus for realising spatial sound effects. The essence of the invention is the division of one or more recorded signals before amplifying prior to reproduction into more parts with summarized power substantially equal to that of the recorded signal and reproduction of the divided signal parts with at least four acoustic radiators. The apparatus includes a transformation unit (A) and a reproducing or recording unit (B) wherein the transformation unit (A) includes controlling means (5) and controlled dividing means (2) wherein the controlled dividing means (2) are equipped with a circuit connected to the output of the controlling means (5) for dividing the electric signal forwarded from the input (6) of the transformation unit (A) substantially without losses for at least four advantageously eight outputs (7).

Description: METHOD OF AST) -APPARATUS FOR REALISING SPATIAL SOϋl * TO EPF3CTS The invention relates to a method of and an apparatus for realising spatial sound effects especial- ly as a part of a program controlling a theatre performance. The proposed method and apparatus are capable of involving conditions in which the acoustic impression of spatial movements is gained by the listeners. The listeners of a recording made on a gramophone record or on a magnetic tape gain the impression of an acoustic space by different methods. The best known methods are the stereophony and the quadrophony prescribing the use of two and four acoustic radiators, respectively, or by embodiments improved for theatre and other large scale performances of the methods, twice more. In the case of the basic embodiments the selected acoustic space is divided into parts and these parts comprise the sound detector units producing electromagnetic signals to be recorded. The recording should be reproduced in an arrangemen of the acoustic radiators which is similar to that of recording. This requires complicated arrangements not only in recording, but in reproducing. Another requirement to the stereophonic and quadrophonic recordings is to ensure the possibility of reproducing them in monophonic and stereophonic systems and this involves the necessity of taking into account the phase relations in the space in order to avoid the disturbing interference effects during recording. OMPI - 2 - It is kno7/n that in the stereophony there is a straight linear section between the acoustic radiators where the impression of an acoustic space can be gained with relatively high fidelity. The quadrophony can be suggested for gaining better subjective impressions, however, with more complicated equipment and higher costs,_ where it is a special problem that there is no recommendation accepted by the manufacturers and the users which of the possible non-compatible systems should be preferred. Another problem of the stereophony and the quadrophony is the case when a small acoustic space should be reproduced in a large space. The high-quality reproduction requires expensive methods of determining the place and the parameters of the acoustic radiators. This relates especially to the different theatre and -other performances realised in large * spaces uuder requirement of high sound fidelity, A further problem of the theatre technique lies in the possible lack of synchronous applying the special light, stage, sound and other effects required during the performances. The mentioned effects are controlled generally by different controllers, however, the cooperation between them is given up-to-date only by visual way. This is the source of many problems. The aim of the present invention is to realise a method and an apparatus for induction the high fidelity impression of an acoustic space especially in large spaces, a method and an apparatus which can be a part of a complex system controlling the special effects of a performance. The invention is based on the recognition that the large space reproduction does not really require the application of stereophonic or quadrophonic solutions. A simple recording can be reproduced by means of a higher number of acoustic radiators under the requirement that the sequence of the work and the loudness of the acoustic radiators be given and altered for inducing the impression that the source of the sound is in a well-determined point or in movement. The object of the invention is to make use of the above recognition and to create a method and an apparatus capable of inducing the impression of a sound space especial¬ ly of a moving sound source on the basis of a simple record- ing which can be also monopionic. Thus, the object of the invention is a method of realising spatial sound effects, especially for use during theatre and other large space performances, comprising the step of amplifying a signal recorded in an acoustic space and reproducing the amplified signal on more acoustic radiators, and according to the invention including the steps of dividing the recorded signal before amplifying into more parts with summarised acoustic power substantial¬ ly equal to that of the recorded signal, and reproducing the amplified signals corresponding to the divided signals - in known manner -, wherein using at least four, advantageously eight acoustic radiators for reproducing. The summarized power of divided signal can be less than the power of the recorded signal, however, only with the losses caused by the dividing operation. More complicated sound effects can be realised when reproducing signals recorded according to the acoustic space of more sound sources. The sound effect can be repeated very easily when recording the signal on a more-track magnetic tape and record¬ ing a control program on another track of the magnetic tape and performing " the program during reproduction. The complex control of effects and other operations required in a theatre not only during performances can be realised in this way it is especially advantageous to control the light effects and the stage craft during realising the spatial sound effects. The object set can be reached also by an apparatus, comprising a transformation unit with inputs forwarding acoustic information in form of electric signals and a reproducing or recording unit connected to the inputs of transformation unit, 7/herein according to the invention the transformation unit includes controlling means and controlled dividing means wherein the controlled dividing means are equipped with a circuit connected to the output of the controlling means for dividing the electric signal forwarded from the input of the transformation unit substantially without losses and for giving them to at least four, advantageously eight outputs. It is advantageous for reproducing more recordings when the ' transformation unit comprises respective integrators before each output, wherein each integrator is connected via the controlled dividing means and/or directly to at least two inputs of the transformation unit. More complicated sound effects can be realised, if necessary by mixing, when the transformation unit includes a multiplexer unit and at least two controlled dividing means connected to the outputs of the controlling means to at least two inputs via the multiplexer means and to the outputs over the integrators. In another advantageous embodiment of the invented apparatus the transformation unit comprises a different number of inputs, controlled dividing means and integrators. Well-defined sound effects can be realised jf the controlling means comprise a circuit for periodic generating a sound effect, e.g. a four-phase generator. The complex control of the work of different kinds of equipment used in a theatre can be realised when the controlling means is based on a microprocessor. , -°2≤ Λ In this case it is advantageous to equip the transformation unit with controlling outputs connected to outputs of the controlling means and to units generating control signals for a light controller, a stage craft controller and other equipment. The method and apparatus as proposed by the invention are capable of displaying an electric signal between more .acoustic radiators in order to ensure the impression of different, if desired moving souαd sources with high fidelity. On the basis of the method the apparatus can be used for controlling different visual and technical elements of a performance, too. The invention will be described now, purely by way of example, on the basis of some embodiments with reference to the accompanying drav/ings including a unique Figure: the arrangement of the apparatus according to the invention realised with a higher number of inputs. In order to realise the proposed method an arrangement should be completed comprising a higher number, e.g. eight acoustic radiators, a signal source and a dividing unit. The signal source is e.g. a more-track magnetic tape recorder with a tape comprising monophonic recording on at least one track. This recording is the basis of the sound effect to be realised. The signal recorded on the tape is reproduced and the signal won by this way is forwarded to the dividing unit. This unit is characterised by the fact that the signal can be divided substantially without losses into more parts as desired, These parts can be of equal or different power values according to the .equirements. The obtained part signal can be amplified and so should be forwarded into the acoustic radiators. The division means that the s unds taken fron the monophonic recording are reproduced on the acoustic radiators in a time sequence and with acoustic /•* o - power chosen according to the sound effect to be realised. This requires of course that the spatial arrangement of the acoustic radiators be taken into account. Having a monophonic recording of a moving plane to be reproduced with the spatial effect of moving at least two, e.g. seven acoustic radiators should be arranged on each side of the auditorium along a straight line. During reproduction the recording the acoustic radiators on the both side should be driven after each other with equal acoustic power. The listener sitting between the two lines of the acoustic radiators gains the impression of a plane flying over his head and moving away to the middle line of the radiators. If changing the acoustic power of the radiators the impression of movement along a curved line can be induced in the listener, The method according to the invention can be - used for recording acoustic signals to be used later during the performances. " In this case it is desired to use a ore- -track magnetic tape recorder and a track of the tape can be applied for recording a program. It is also possible to record on the tracks the different signals to be reproduced on different acoustic radiators. The signals of the different tracks can be performed by different dividing units the output signals of which can be integrated according to a predetermined program. In this way very sophisticated acoustic spatial effe cts can be realised. The apparatus according to the invention (Figure) is capable of realising the proposed method and consists of two main parts, i.e. a transformation unit A and a reproducing or recording unit B. The transformation unit A is connected over inputs 6 with sound signal sources 1, e.g. magnetic tape recorders and/or sound sensitive means, as microphon. It includes a multiplexer M connected to a controlled dividing means 2 driven by controlling means 5-» The outputs of the controlled dividing means 2 are connected directly or over integrators 3 to outputs 7 of the transformation unit A and thereby to the inputs of the unit B. This unit includes amplifiers 4 for dividing sound radiators 9 or a magnetic tape recorder for registrating on more tracks. The desired sound effects can generally be realised on the basis of four acoustic radiators 9, however, according to the experience it is more convenient to use a higher number, e.g. eight radiators 9. Of course the sound effect to be realised may require a higher and a lower number of the acoustic radiators, then eight, however, their number is not lower then four. There is a variety of circuit arrangeπe rats of the transformation unit A possible. The main distinguishi feature can be seen in the number of the controlled dividing means 2 used. If o y one controlled dividing means 2 are in the apparatus there is no need to use the multiplexer M and the controlled dividing means 2 are connected direct- ly to the inputs β for dividing the electric signals which should correspond to only one sound source. This is the most simple embodiment and the outputs 7 of the transforma¬ tion unit A can be connected directly to the controlled dividing means 2 for driving the unit B. Wit a higher number of controlled dividing means 2 it is possible to have sound effects on the basis of higher number of sound signal sources 1. Of course this embodiment should allow the realisation of more • complicated sound effects then that comprising one controlled dividing means 2. In this case the multi¬ plexer M is arranged between the inputs 6 and the corresponding controlled dividing means 2. The multi¬ plexer M and the controlled dividing means 2 may have control inputs and can be connected thereby, too. The multiplexer M has the object to combine the signals received from the inputs 6 in a predetermined manner, i.e. the outputs of the multiplexer M forward signals produced by mixing the signals of different inputs 6. The mixed signals are divided in the controlled dividing means 2 connected to the integrators 3, The number of the integrators 3 is advantageously equal to the number of the inputs of the unit B, i.e. the sound radiators 9 with amplifiers 4 or the tracks to be used in a magnetic tape recorders. The integrators 3 are connected to a higher number of the controlled dividing means 2. All embodiments of the transformation unit A can be characterized by lack of amplifying or attenuation wherein the only energy dissipation is the consequence of the use of passive different electric elements. The number of the controlled dividing means 2 * * and integrators 3 can be different. It is possible to use more integrators 3 wherefrom several are connected to some of the controlled dividing means 2. This is also a possibility of realising special sound effects. ' An- other embodiment will include integrators 3 connected directly to respective inputs 6, This is an advantageous solution when a special noise or music should be reproduced without any spatial effect (background noise or music), As mentioned the multiplexer and the controll¬ ed dividing means 2 shouldn't cause any information. losses - they are neither amplifiers nor attenuators and are aimed only for dividing the input signals into respective parts. This division can be done with continouos change of the acoustic power (the impression of dissolving one sound into another or of continouos movement) or in discrete steps, if necessary at the same time for the different acoustic radiators. The controlling means 5 can be a very simple unit with potentiometers for regulation of the acoustic power if the apparatus should be used only for realisation of simple sound effects. It may include also circuit elements for repeated applying a defined sound effect. For example a four-phase generator can be very helpful if the impression of a sound source moving along the line of the radiators around the listener should be realised. The more developed embodiment of the controlling means 5 includes a microprocessor unit having a program for controlling different units over controlling outputs 8. These units can be e.g. the sound signal sources 1 during recording or interface units 10, 11 producing commands for light controller and stage craft controller in a theatre. In this way it is possible to create a complex controlling system for a theatre which can realise according to a predetermined program all special effects required during the performance. Of course, a smoke generator and other units can be controlled in this way, too, and if required the other mechanical theatre equipment as well. The equipment can include e.g. the ventillation and heating, etc. The most developed embodiment of the controlling means 5 is a computer the use of which is required, horarer, in cases when a high amount of information should be processed during realisation different tasks, as special sound, light and other effects, operating the stage craft etc. In a realised embodiment of the proposed apparatus the noise/signal value has been as high as 90 dB, the distortion of the signal has remained as low as 0,2 % * In this apparatus signals corresponding -to two sound sources can be divided into eight parts, for respecϋve eight acoustic radiators. The method and apparatus according to the inven- tion render realisation of high fidelity spatial sound effects possible.

Claims: CLAIMS: 1. Method of realising spatial sound effects, comprising the steps of amplifying a signal recorded in an acoustic space and reproducing th-e-amplified signal on more acoustic radiators, c h a r a c t e r i s e d in the steps of dividing the recorded signal before amplifying into more parts with summarized acoustic power substantial¬ ly equal to that of the recorded signal, and reproducing the amplified signals corresponding to the divided signals, wherein using at least four, advantageously eight acoustic radiators for reproducing. 2. Method of claim 1, c h a r a c t e r i s e d in reproducing signals recorded according to the acoustic space of more sound sources. 3, Method of claim 1 or 2, c h a r a c t e r i s ¬ e d in recording the signal on a more-track magnetic tape and recording a control program on another track of the magnetic tape and performing the program during reproduc¬ tion. 4. Method of claim 3, c h a r a c t e r i s e d in controlling the light effects and the stage craft during realising the spatial sound effects. 5. Apparatus for realising spatial sound effects, especially for theatre performances, comprising a transforma¬ tion unit with input forwarding acoustic information in form of electric signals and a reproducing or recording unit connected to the inputs of transformation unit, c h a r a c t e r i s e d in that the transformation unit (A) includes controlling means (5) and controlled dividing means (2) wherein the controlled dividing means (2) are equipped with a circuit connected to the output of the controlling means (5) for dividing the electric signal forwarded from the input (β) of the transformation unit (A) substantially ' without losses for at least four, advantageous- - Il ¬ ly eight outputs (7), 6, Apparatus according to claim 5 » c h a r a c t e r i s e d in that the transformation unit (A) comprises integrators (3) before the outputs (7), where- in each integrators (3) is connected via the controlled dividing means (2) and if necessary directly to at least two inputs (6) of t ' he transformation unit (A), 7, Apparatus according to claim 5 or 6, c h a r a c t e r i s e d in that the * transformation unit (A) includes at least two controlled dividing means (2) connected to the outputs of the controlling means (5) over a multiplexer (M) to at least two inputs (6) and via the integrators (3) to the outputs (7). 8, Apparatus according to claim 6 or 7, c h a r a c t e r i s e d in that the transformation unit (A) comprises a different number of inputs (6), controlled dividing means (2) and integrators (3)» 9, Apparatus according to any of claims 5 to 8, c h a r a c t e r i s e d in that the controlling means (5) comprise a circuit for periodic generating a sound effect, e.g. a four-phase generator. 10, Apparatus according to any of claims 5 to 8, c h a r a c t e r i s e d in that the controlling means (5) is based on a microprocessor. 11. Apparatus according to claim 10, c h a r a c t e r i s e d in that the transformation unit (A) comprises controlling outputs (8) connected to the controlling means (5)» 12. Apparatus according to claim 11, - c h a r a c t e r i s e d in that the controlling outputs (8) are connected to units (10, 11) generating control signal or a light controller and a stage craft controller.

Inventors: BEKESNE GAAL EVA, LENGYEL MIHALY, POLYAK GABOR, BEKESNE GAAL, EVA, LENGYEL, MIHALY, POLYAK, GABOR
Applicants: BEKESNE GAAL EVA, LENGYEL MIHALY, POLYAK GABOR, BEKESNE GAAL, EVA, LENGYEL, MIHALY, POLYAK, GABOR
Application year: 1984
Main classification: H04S5
IPC codes: G11B5, H04R3, H04S5