US3873779A

US3873779A - Electronic sound distribution system

Info

Publication number: US3873779A
Application number: US256516A
Authority: US
Inventors: Gary L Wedan
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-05-24
Filing date: 1972-05-24
Publication date: 1975-03-25
Anticipated expiration: 1992-03-25

Abstract

A sound distribution system for giving the effect of physical dimensions to sound by sequentially and cyclically distributing the sound input signal among a plurality of output channels to which are connected corresponding speakers located along the perimeter of a listening area. The sound distribution system comprises an electronic apparatus that sequentially ungrounds the speakers by sequentially turning off gates that are connected between ground and the output channels. The gates are sequentially turned off by a plurality of trains of switching signals that are phased apart so as to present the individual switching signals to the gates in sequence.

Description

[4 Mar. 25, 1975 1 ELECTRONIC SOUND DISTRIBUTION SYSTEM [75] Inventor: Gary L. Wedan, Duluth, Minn.

[73] Assignee: Robert Urbick, Duluth, Minn. a

part interest 22 Filed: May 24,1972

[21] Appl. NO.Z 256,516

[52] US. Cl...... 179/1 GQ, 179/1 G, l79/l00.4 ST,

179/100.l TD [51] Int. Cl. H04r 5/00 [58] Field of Search 84/D1G. l, DIG. 27; 179/1 G, 1 GP, 1 GQ, 100.1 TD

[56] References Cited UNITED STATES PATENTS 2,114,680 4/1938 Goldsmith 179/1 GP 2,792,449 5/1957 Bottini l79/l00,l TD 2,832,829 4/1958 Reynolds... 179]] GP 2,927,963 3/1960 Jordan 179/1001 TD 2,931,862 4/1960 Vermeulen et a1. 84/DlG. 1 2,941,044 6/1960 Volkmann 84/D1G. 1 3,018,335 l/l962 De Rosa 179/1 G 3,272,906 9/1966 De Vries..... 3,374,315 3/1968 Gladwin 179/1 G 3,375,329 3/1968 Prouty l79/l00.l TD 3,586,783 6/1971 Brickner.. l79/l GQ 3,654,394 4/1972 Gordon 179/15 BL 3,665,105 5/1972 Chowning 179/1 J 3,684,835 8/1972 Orban 179/1 GP 3,757,046 9/1973 Williams l79/l GQ Primary Examiner-Kathleen H. Claffy Assistant Examiner-Thomas DAmico Attorney, Agent, or Firm-Larson, Taylor & Hinds [57] ABSTRACT A sound distribution system for giving the effect of physical dimensions to sound by sequentially and cyclically distributing the sound input signal among a plurality of output channels to which are connected corresponding speakers located along the perimeter of a listening area. The sound distribution system comprises an electronic apparatus that sequentially ungrounds the speakers by sequentially turning ollgates that are connected between ground and the output channels. The gates are sequentially turned off by a plurality of trains of switching signals that are phased apart so as to present the individual switching signals to the gates. in sequence.

18 Claims, 7 Drawing Figures PAIENIEDMRZS

197s sum

2 or 4 3 mm we 1 iT /zfllll MENTEUMRZS i975 SPEAKER '0 I I l I snmaurq XPEAKER "A" SPEAKER B" I I90 SYNC l 7 g OUT o scum) DIST 3 (I76 SYSTEM [4 A AMP. s CHANNEUA" *1 l rlfil M 1?? |ss smc sgg z B I 4 AMP, CHANNEL B souuo DISTES SYSTEM#24 c R 1AMP. CHANNEL 0 *1 :79 I85 smc i D W CHANNEL D scum) DIST3 SYSTEM#34 FIG. 6

W'EMEUH z a sum u q PHASE H 13 ROTATION 2nd ROTATION 1 3rd ROTATION ELECTRONIC SOUND DISTRIBUTION SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an electronic system for c'yclically distributing an input sound among a plurality of speakers to thereby give the sound as heard by a listener added dimensions of form, motion and space.

2. Description of the Prior Art The concept of selectively distributing sound to variously located speakers is, of course, conventional. An early system employing this concent was used to create a stereo effect from a monoaural recording. Reference is made to a U.S. patent to Palladino', U.S. Pat. No. 3,219,759 which discloses a system using two speaker channels and an electronic circuit for splitting the phase of a monoaural sound input and for delaying one of the channels by an amount that varies in a non-linear manner with the frequency.

Other patents have discussed the use of a plurality of speakers to simulate a large-area sound source as opposed to a point source that results from the use of only one speaker. In U.S. Pat. No. 2,114,680 to Goldsmith, one embodiment of the invention employs a plurality of speakers connected in parallel to a sound input signal through corresponding amplifying tubes. Superimposed on the grids of the tubes are auxiliary alternating voltages that have a phase difference such that when one tube is conducting at a maximum, the other tubes are at a minimum, and the source of the sound effect shifts from speaker to speaker at a frequency equal to that of the applied alternating grid voltage. A U.S. patent to Reynolds, U.S. Pat. No. 2,832,829 discloses a mechanical system for achieving sound distribution. The system rotates a circular ring through a plurality of equally spaced coils each coil being connected between ground and a corresponding speaker. The ring is basically formed from a dielectric material, but an arcuate sector of the ring is made up of an iron slug so that when the slug passes through the coil, the speaker is grounded. Systems like those disclosed in these two patents have a number of disadvantages. For example, switching noise is induced into the speakers when the switching between speakers occurs. Further, such systems provide very poor control over the switching fre quency. Mechanical systems suffer obvious disadvantages regarding wear, reliability, cost, size and weight.

SUMMARY OF THE INVENTION According to the present invention, a completely electronic sound distribution system is provided which cyclically distributes an input sound signal among a plurality of speakers. The cycle or switching frequency among the speakers is both easily adjustable in' small increments and continually adjustable over a continuous range of frequencies. In addition, the system of the invention is such that no perceptible switching noise is picked up by the speakers.

The preferred embodiment of the invention employs four speakers which are normally grounded through a switchable gate. A plurality of switching signals are generated for sequentially turning off the gates, thereby sequentially ungrounding the speakers'and permitting the corresponding ungrounded speaker to respond to a sound input signal which is coupled in parallel to all the speakers.

A system in accordance with this embodiment of the invention accomplishes the desired sound distribution through the provision of a coupling network for coupling the sound input signal to the system in parallel to a plurality of speakers. Each of a plurality of signal responsive electronic switching devices, equal in number to the number of speakers, selectively grounds a corresponding speaker, each speaker when ungrounded, being responsive to the sound input signal. A plurality of trains of switching signals are generated which are equal in number to the number of speakers, and which differ in phase so that switching signals or pulses are presented sequentially to corresponding switching devices and hence that the switching signals sequentially actuate the corresponding switching devices thereby producing a cyclic distribution of the sound input signal to the speakers.

Other features and advantages of the present invention will be set forth in or apparent from the detailed description of the preferred embodiment of the invention found hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic block diagram of one embodiment of the invention;

FIG. 2 is a detailed schematic circuit diagram of the embodiment of the invention shown in FIG. 1;

FIG. 3 is a graph of the voltage wave forms at various points in the circuit of FIG. 2;

FIG. 4 is a plan view of a schematic representation of travelling sound waves produced by the speakers of the system of the invention with different parameters held constant;

FIG. 5 is a graphical representation, in polar coordinates, of the wave forms of several musical sounds;

FIG. 6 is a schematic block diagram of a system combining three synchronized embodiments of the invention;

FIG. 7 is a graph of the voltage wave forms which are presented sequentially to corresponding switching devices.

DESCRIPTION OF THE PREFERRED EMBODIMENT Although the structure and operation of the invention will be described with respect to a presently preferred embodiment of the invention, it will, of course, be understood that the particular values of the components given are merely illustrative and that these values may, of course, be varied without departing from the scope of the invention.

Referring to FIG. 1, a block diagram of a system in accordance with a presently preferred embodiment of the invention includes a high impedance terminal 11 and a low impedance terminal J2 for receiving the sound input signals. A preamplifier l3, connected to terminals 11 and J2, amplifies the input signal and is, in turn, connected in parallel to a plurality of signal responsive switch means, such as

electronic gates

16, 17, 18 and 19. Gates I6, 17, 18 and 19 either pass the input signal to respective outputs, such as output terminals JA, 18, JC and JD, or ground the input signal, at respective grounds indicated at 26, 27, 28 and 29, depending upon the presence or absence of a switching signal at the respective gate. Alternatively, the input signal can be directly coupled to gates l6, l7, l8 and 19 by bypassing preamplifier 13 through an auxiliary input output terminal J8.

Four signal trains of switching signals, one signal train corresponding to each of the four gates l6, l7, l8 and 19 and consequently to each of the four output terminals JA, JB, JC, and JD are generated by further circuitry, the signal trains differing in phase such that the switching signals from the individual signal trains are presented sequentially to

gates

16, 17, 18 and 19. More specifically, an oscillator 40 generates a train of timed pulses which are delivered, through a switch S4, when the contact arm of switch S4 is positioned at a first terminal denoted 41, to a transistor driver circuit 42. Transistor driver 42 amplifies the pulses which are then applied, through a switch S2, to a first frequency divider network 45 when the contact arm of switch S2 contacts a first terminal 43, i.e., with switch S2 in position 43, or to a second frequency divider network 49 with switch S2 in the second position thereof, in contact with terminal 47. With switch S2 in the first position thereof, divider 45 divides the frequency of the train of pulses generated by oscillator 40 in half. The train of pulses is then transmitted to divider 49 which further divides the frequency in half by generating, from alternate pulses in the train, first and second subtrains of timed pulses. The first sub-train of pulses is applied to square wave generator 50 whereas the second sub-train of pulses is applied to a square wave generator 51. The first pulse from divider 49 is applied to square wave generator 50, which in turn transmits a square wave switching signal from a first output thereof to a first controller 53. The next pulse from divider 49 is applied to square wave generator 51 which transmits a square wave switching signal from a first output thereof to a second controller 56. Similarly, the third pulse from divider 49 is applied to square wave generator 50 which transmits a square wave switching signal from the second output thereof to a third controller 54, while the fourth pulse from divider 49 is applied to square wave generator 51 which transmits a square wave switching signal from the second output thereof to a fourth controller 57. Hence, the first four input pulses to divider network 49 are squared up by

square wave generators

50 and 51 and applied to separate

controllers

53, 56, 54 and 57.

Controllers

53, 56, 54 and 57 are individually coupled to, and control switching of, gates l6, 17, 18 and 19, respectively. Because each controller is actuated by a train of switching signals which differs in phase from the switching signals in the other trains,

controllers

53, 56, 54 and 57, in turn, sequentially actuate the corresponding gates l6, 17, 18 and 19 to thereby produce a revolving or cyclic distribution of the input signals to the output terminals JA, JB, JC, and JD. Thus, to review the system so far described, a trainof timed pulses is used to generate four trains of square wave switching signals, which differ in phase from one another and which produce the cyclic distribution of the sound input discussed herein above. Although the. preferred embodiment uses four speakers, the invention is not to be limited to this number.

It may also be desirable to connect a number of individual sound distributions systems in parallel, such as is shown in FIG. 6. This can be accomplished by switching switch S4 from position 41 to position 60, thereby disconnecting oscillator 40 from the circuit and connecting in a synchronizingpulse inputreceived at a sync" input terminal J5. A synchronizing output signal can be transferred to other sound distribution sys tems through a further sync output terminal J4 that is tapped off at the input to controller 53 from the switching signal generated by square wave generator 50.

In addition, switch S2 may be used in selective ones of the parallel connected sound distribution systems to provide a different frequency of cyclic distribution of the input signals, i.e., a frequency of either one-half or double the frequency of the non-selected sound distri bution systems.

The cycle frequency can be defined as either the number of times any one gate is turned on per second or as the number of revolutions among the four outputs that the input signal makes per second. This cycle frequency can be varied by a manual frequency control input 65 connected to oscillator 40 through a switch S3 which is in the first position in contact with a first terminal 66. Alternatively, with switch S3 in the second position thereof in contact with a second terminal 68, a foot pedal controlled input 69 is connected to oscillator 40 to control the frequency thereof. Both foot pedal frequency control input 69 or manual frequency control input 65 can be variably adjusted to provide a variable output frequency thereby varying the cycle frequency, or can be continually adjusted to provide a varying output frequency, thereby producing a varying timed relationship between switching signals in the same cycle in addition to producing a variable output frequency between cycles. The cycle frequency can be monitored through a scanner 70 having a visual indication 71, which blinks once per cycle corresponding to each time a switching signal from square wave generator 50 actuates controller 54.

Referring to FIG. 2, there is shown a schematic circuit diagram of the block diagram of FIG. 1. Although the circuit will be described only in general terms and reference will be made only to major components, all components are identified to that respectative values thereof can be obtained by reference to the list of components found hereinbelow. Where applicable, like components in FIGS. 1 and 2 are designated by like identifying symbols. I

As desired, high impedance and low impedance sound inputs are provided at input terminals J1 and J2, respectively. An electrical ground G1, corresponding to

individual grounds

26, 27, 28 and 29 in FIG. 1, is connected to terminal J2 through ground line or bus 201 and a resistor R35. The high impedance input terminal J1 is connected through a conductor 202 to the pre-amplifier referred to above which includes a coupling capacitor C56 and first and second field effect transistors (FETS) T1 and T2. The output of this preamplifier which taken at the collector of transistor T2 is connected through a gain control resistor R60 and input line 204 to output terminals JA, JB, JC, and JD. Alternatively, as mentioned above, the pre-amplifier can be bypassed and the input signal can be directly coupled to the outputs through auxiliary terminal J8 and an isolation resistor R20. Output terminals JA, JD, JC and JDiare connected in parallel to input line 204 through respective isolation resistors R21, R22, R23, and R24 and coupling capacitors C31 and C41, C32 and C42, C33 and C43, and C34 and C44. The other line 201.

' sistors have both a high input impedance and a high output impedance, thereby minimizing the amount of switching noise induced into the corresponding output terminal and use a very small signal at the gate to control a very large signal through the transistor, further tending to minimize induced switching noise.

As described hereinabove, the signal trains of switching signals are developed from a single train of timed pulses by a plurality of successive stages. The train of timed pulses is generated in oscillator 40 that includes transistors T3 and T4 in a conventional astable multivibrator circuit. Also as described, the frequency of the output signal of oscillator 40 can be varied manually or with a foot pedal control, and, more specifically, is in part determined by the resistance of a manually controlled resistor R10A or by the resistance of a foot pedal controlled resistor R10B, depending on the position of switch J3.

The output of oscillator 40 is connected through switch S4, in the first position thereof, through coupling capacitor CS1 to the transistor driver 42 which was referred to above and which includes cascaded transistors T and T6. Alternatively, the input to driver 42 can be taken through sync input terminal J5 if switch S4 is the second position thereof. The driver output, which is an amplified train of timed pulses, is connected through switch S2 to a network of four bistable multivibrators or flip-flops FFl, FF2, FF3 and FF4 which are formed by transistors T to T17 and resistor packs RPl, RP2, RP3 and RP4.

Flip-flops FH and FF2 are used as frequency dividers and flip-flops FF3 and FF4 are used as square wave generators. With switch S2 in the terminal 47 contact position flip-flop FFl is bypassed and the output from driver 42 triggers flip-flop FF2. with switch S2 in the terminal 43 position, the output from driver 42 is applied to flip-flop FFl which divides the frequency of the signal by half. The signal from the righthand output of flip-flop FFI is applied to flip-flop FF2 through coupling capacitor C53. As is well known in the art, provision can be made for taking the output of a flipflop at either side of the flip-flop circuitry and, at any one time, one side of the flip-flop will be in a high state while the other side will be in a low state. Thus a single input signal can generate two output signals that are exactly 180 out of phase. In this manner, the right-hand output of flip-flop FFZ is applied through coupling capacitor C55 to flip-flop FF3 and the left-hand output of flip'flop FF2 is applied through coupling capacitor CS4 to flip-flop FF4. The right-hand and left-hand output from flip-flop FF3 is respectively taken by conductor 211 and conductor 213 and the right-hand and lefthand outputs from flip-flop FF4 are respectively taken by conductor 212 and conductor 214.

Controllers

53, 54 56 and 57 shown in FIG. 1 are identical and include, respectively, switching transistors T21, T22, T23 and T24 shown in FIG. 2. Only the circuit components connected to switching transistors 21 will be described in detail with reference to FIG. 2, the circuit components connected to the other switching transistors being identical. Corresponding circuit components connected to the switching transistors are identified with the same numeral in the tens position of the identifying symbol, and all circuit components connected to the same switching transistor are identitied with the same numeral in the ones position" of the identifying symbol. Switching transistor 21'!" is an npn transistor having a collector 301, an emitter 302 and a base or gate 303. Emitter 302 is connected to the gate of gating transistor T31 through an output resistor R41 and a shaping capacitor C11 is connected across collector 301 and emitter 302. Connected to gate 303 is the parallel combination of a shaping capacitor C21 and a control signal input resistor, or control resistor R31. A wave shaping integration network is connected between ground line 201 and the junction between output resistor R41 and gating transistor T31 and comprises a resistor R51 and a capacitor C61 connected in parallel. A positive signal appearing at a control resistor R31 turns on switching transistor T21 which, when conducting, provide a low impedance path between collector 301 and the emitter 302, thus passing any signal appearing at the collector to the gate of gating transistor T31.

Scanning network includes cascaded transistor T7 and T8 and a light B2 connected at terminals J6. The input to scanning network 70 is taken from the lefthand output of flip-flop FF3 through a resistor R25.

The power supply for the circuit is a standard DC power supply comprising an AC input connected through a power control switch S1, a power indicating light B1, a step-down transformer Trl, a full wave rectifier comprised of diodes D1 and D2, and a wave shaping filter comprised of capacitor C1 and C2 and resistor R16.

The flip-flops FFl through FF4 function so as to produce four out of phase trains of square wave switching signals from a single train of timed pulses, each switching signal being a half cycle (180) in duration and differing in phase by a quarter cycle or from the corresponding signal from the preceding signal train. For simplification, it is assumed that switch S2 is in the terminal 47 position, thereby bypassing the flip-flop PH and effecting a doubling of the frequency that would have resulted had flip-flop FFl been in the circuit. The first pulse from the driver changes the output from the right-hand output of flip-flop FF2 to, for example, the high state and the left-hand output to the low state. Coupling capacitors C55 and C54 respectively differentiate these two square wave signals producing, respectively, a first signal that triggers flip-flop FF3 and a second signal which is transmitted to but does not change thestate of flip-flop FF4. The triggering of flipflop FF3 produces, for example, a high state square wave switching signal from the right-hand output that is transmitted by conductor 211 to collector 301 of switching transistor T21, to shaping capacitor C23 at the base of switching transistor T23, and to the control resistor R34 connected to the base of switching transistor T24. If this switching signal isi arbitrarily designated the first switching signal and switching transistor T21 is the first controller, it can be seen that the switching signal is distributed to the first, third and fourth switching transistors (i.e., T21, T23 and T24) which correspond to the first, third and fourth controllers (i.e.,

controllers

53, 54 and 57) in FIG. 1.

The next pulse from driver 42 switches the states of flip-flop FFZ such that the left-hand output is at a high state and the right-hand output is at a low state. The high state output is differentiated by coupling capacitor C54 and is applied to flip-flop FF4 to cause triggering thereof and the low output is differentiated by coupling capacitor C55 and results in a second signal which is applied to but does not change the state of, flip-flop FF3. Thus, whereas the state of flip-flop FF3 is not affected by the second pulse from the driver. this second pulse will change the states of the outputs of flip-flop FF4. For example, the right-hand output of flip-flop FF4 is switched to a high state and the left-hand output to alow state. Connector 212 transmits the right-hand output of flip-flop FF4 as a square wave switching signal to the collector of switching transistor T22, shaping capacitor C24 of switching transistor T24 and control resistor R31 of controller 53 (i.e., to the second, fourth and first controllers). Switching transistor T21, normally in the offstate, did not transmit the first switching signal from the RP3 flip-flop to the gate of gating transistor T31 the instant it was transmitted thereto. However, as soon as the second switching signal, generated as a square wave switching signal from the right-hand output of flip-flop FF4, is transmitted, 90 later in the cycle to control resistor R31, switching transistor T21 is turned on and the first pulse that was earlier applied to collector 301 is now transmitted through switching transistor T21 to the gate of gating transistor T31. Due to the effects of capacitor C11 and the parallel combination of resistor R51 and capacitor C61, the square wave switching signal is given a rounded leading edge and a lengthened trailing edge, thereby reducing the switching noise induced in output terminal JA. and gradually turning off gating transistor T31, as explained below. Thus, the width or time duration of the square wave switching signal, as generated, is decreased by chopping off the leading portion of the signal an amount equal to the time lag or phase difference between the sequential generation of the square wave switching signals.

Gating transistor T31 is normally conducting and thus the input signal to output terminal IA is grounded. However, when the first switching signal is applied to the gate of gating transistor T31, transistor T31 is back biassed and gradually turned off, thereby gradually increasing the amplitude of the input signal transmitted to the outputterminal JA. 7,

In a similar manner, the third pulse from driver 42 is applied to flip-flop FF2, which again changes its states, the positive pulse from the right-hand output being applied to and triggering flip-flop FF3. The states of the flip-flop FF3 are then changed and a square wave switching signal appears at the left-hand output which is coupled, through connector 213 and capacitor C21, to control resistor R32, turning on switching transistor T22, and to the collector of switching transistor T23 as a square wave switching signal. The square wave switching signal at transistor T21 now disappears and the trailing edge of the square wave that is applied to gating transistor T31, as shown in FIG. &, is rounded off by capacitor C21 and the parallel combination of R51 and C61. Thus, the amplitude of the input signal transmitted to output terminal IA is gradually decreased thereby permitting a mementary, simultaneous presentation of the input signals to output terminals JA and J B.

Referring to FIG. 3, the square wave switching signals are shown as they would appear at the output of the respective controllers 53, S6, 54 and 57. if there were no rounding of the square wave. Rounded square wave switching signals are shown in FIG. 7 as they appear at the input to the gates of gating transistors T31 to T34 At 0 and time zero, no switching signal has been produced. later the first square wave switching signal and the train of signals B1 appears at the output of controller 53, FIG. 1. Then the square wave switching signals B2, B3 and B4 sequentially appear at the outputs of, respectively,

controller

56, 54 and 57, FIG. 1, at times of 180, 270 and 360 in the first cycle, respectively.

Thus, with reference to FIG. 1, as was described in somewhat different terms hereinabove, the first square wave switching signal generated by the first pulse from driver 42 is delayed for approximately 90 before being applied to gate 16 because controller 53 has not been turned on. The second square wave switching signal turns on controller 53 and allows the remaining approximately 90 of the first square wave switching signal to pass through to gradually turn off gate 16 thereby ungrounding output terminal JA. Each square wave switching signal is consequently delayed for approximately 90 at the respective controller before the controller is turned on by the next subsequent square wave switching signal. The net result of the switching signal circuitry is that described above, i.e., the sequential turningoff of the gates, causing a sequential ungrounding of the output terminals and a resultant rotational or cyclic distribution of the input signal among the output terminals.

Referring to FIG. 4, the rotational or cyclical sound distribution of three different types of signals among four speakers A, B, C and D is shown schematically. FIG. 4 illustrates that through a change in the rotational speed of the signal, such as provided by adjustment of resistor R10A or R108 of FIG. 2, and/or an independent change in the input signal amplitude, and/or a change in the input signal timing, the effects of motion or movement, form and musical structure can be sensed by a listener located in a listening area 155, the perimeter of which is defined by the location of speakers A, B, C and D. More specifically, path indicates the motional effect produced by a continuous signal without a change in the signal amplitude. Path 152 indicates the effect produced by a broken signal or one intermittently applied to the input of the sound distribution system, the amplitude of the signal still remaining constant. Path 154 indicates the effect created by a signal having both changes in amplitude and in the rotational speed. The changes in the amplitude of the signal move the signal in and out from the center 156 of listening area 155.

The examples of sounds that can create the signal paths depicted in FIG. 4 are shown in FIG. 5. In the FIG. 5 graph, is equivalent to one measure of musical time notation and exemplary sound levels are indicated by concentric circles 100 of decreasing amplitude in decibels (db). Wave form 111 is a constant low frequency square wave sound signal changing 15db in amplitude every six cycles, four equal times every half measure. If gain control resistor R60 in FIG. 2 were set at the 15db level, the low amplitude signal, denoted 113, FIG. 5 would be attenuated and onlythe spikes, denoted 114, would be audible at the speakers. Further, if the rotational distribution rate among speakers were set equal to the musical timing, the result would be similar to that illustrated by path 152 in FIG. 4. The dimension of distance or space can be obtained with the same signal by increasing the gain of the signal and rendering the low amplitude part 113 audible.

Other forms" of musical sounds are depicted at 120 and 125 in FIG. 5. Form 120 is a pulsed mid-frequency half note that is centered about the 20db gain and form 125 is a sharp sixteenth note that can be obtained, for example, from the pluck of a guitar string. It will be appreciated that by systematically varying the resistances of resistors RIOB or RNA in FIG. 2, the sound distribution of a musical score can be given an infinite variety of physical" dimensions.

Through the use of the sync inputs and outputs and the proper positioning of switch S4, FIGS. 1 and 2, one sound distribution system can be set up as the master and can be coupled to a plurality of slave sound distribution systems. It is to be understood that the masterslave relationship refers only to the generation of switching signals and does not refer to the sound input that is to be distributed among the plurality of speakers. Thus, referring to FIG. 6, a master sound distribution system 160 is coupled by connector 165 to a slave sound distribution system 161. Sound distribution system 161, in turn, is coupled through the sync output terminal thereof, by connector 167, to a second slave sound distribution system 162. The embodiment of the invention described above utilizes four outputs, and thus the same numerical output terminal from each of the sound distribution systems is coupled to the same channel in a multichannel mixer 175. Each channel of mixer 175 provides a corresponding output. Each output can be fed to an amplifier, such as amplifier 176 for channel A, amplifier 177 for channel B, amplifier 178 for channel C and amplifier 179 for channel D or can be taken from an amplifier as indicated by taps 190. Each amplifier is connected to a corresponding speaker, such as

speakers

182, 183, 184 and 185.

By appropriately intercoupling a number of sound distribution systems, each having a sound input'representing, for example, one plane of sound, one channel of a multioral recording, a different instument in an orchestra playing the same music and/or different musical tunes and coupling these sound distribution systems through a mixer, such as mixer 175, an infinite number of variations can be produced in the total sound effect sensed by a listener located with in the listening area.

The values for the components shown in FIG. 2 are given hereinbelow:

Component Value Component Value R1 510 C-l lKuf Electrolytic R2 270 K C-2 500 uf do. R3 750 G3 250 uf do. R4 100 K C-4 10 uf do. R5 47 K C-5 uf do. R6 47 K C-6 10 uf do. R7 1K C147 10 uf do. R8 10 C-8 25 uf do. R9 22 K C-1 1 .22 Paper Rl0 1 l M LIN C-12 .22 do. RIOB I M LIN C-13 .22 do. R11 750 C-1 4 .22 do. R12 330 K C-21 .22 do. R13 330 K C-22 .22 do. R14 1 K C-23 .22 do. R15 500 C24 .22 do. R16 750 C3] 1 uf Electrolytic R17 2 K LIN C-32 luf do.

-Contmued Component Value Component Value R18 7.5 K C-33 1 uf do. R19 7.5 K C-34 l uf do. R20 1.5 M C-4l 1 uf R21 47 K 0-42 1 uf R22 47 K C-43 l uf R23 47 K C-44 l uf R24 47 K C-51 .02 Ceramic R25 100 K C- 52 .02 do. R26 12 C-53 .02 do. R27 1.2 K C54 .02 do. R28 100 K C-55 .02 do. R29 K C-56 .001 R30 C-61 .47 Paper R31 50 K C-62 .47 do. R32 50 K C-63 .47 do. R33 50 K C-64 .47 do. R34 50 K Tl 2N5l63 R35 25K T2 2N5163 R36 68 M T3 2N2400 R41 6.8 K T4 2N4105 R42 6.8 K T5 2N3904 R43 6,8 K To 2N3904 R44 6.8 K T7 2N3904 R50 T8 2SC485 R51 1.5 M T9 R52 1.5 M T10 2N4105 R53 1.5 M T1 1 do. R54 1.5 M T12 do. R60 200 K LIN T13 do. R61 K T14 do.

51 SPST S2 SPDT S3 SPDT S4 SPDT RPl A-509-032976 Sprague R1 2 do. RP3 do. RP4 do. J1 High Impedance Input Phone Jack .12 Low Impedance Input Phone Jack J3 Pedal, 3 Conductor .14 Sync Out RCA .15 Sync In RCA J6 Scanner Indication J7 Tape in RCA J8 Aux. Input/Output RCA JA Channel .A" Output RCA .18 Channel 8" Output RCA .IC Channel C" Output RCA JD Channel D" Output RCA TRl VAC to 12.6 VAC.5A B1 NE2 LAS B2 ZOQFilament T15 2N4105 T16 do. T17 do. T21 2N3904 T22 do. T23 do. T24 do. T31 2N5462 T32 do. T33 do. T34 do. D1 1 ET3 D2 1 ET3 Although the invention has been described in detail with respect to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that variations and modifications may be effected within the scope and spirit of the invention.

I claim:

1. A sound distribution system for cyclically distributing sound radiation in a plurality of different directions comprising:

a plurality of speakers located so as to define the perimeter of a listening area;

an input for receiving an electrical input signal corresponding to a sound signal;

means for connecting said input in parallel with said plurality of speakers;

a plurality of switch means, individual to said speakers, for selectively actuating a corresponding said speaker responsive to a switching control signal;

means connected to said switch means for generating a plurality of trains of said switching control signals, equal in number to the number of said speakers, which differ in phase such that the switching control signals from the individual trains are presented sequentially to individual of said switch means so that said switch means are cyclically actuated to cause sequential actuating of said speakers and hence produce a cyclical distribution of sound radiation from said plurality of speakers; and

control means individual to said switch means and coupled to said generating means for selectively coupling one of said trains of switching signals to a corresponding said switch means, said control means being operably responsive to switching signals from a further of said trains of switching signals generated by said generating means.

2. A sound distribution system in accordance with claim 1 and further including preventing means connected in series between each said input and the corresponding said speaker for preventing the grounding of the corresponding said speaker upon the grounding of any other said speaker; and wherein each said switch means comprises a field effect transistor electrically connected in parallel across said speaker, said field effect transistor having a source electrically connected between said preventing means and said speaker, a drain electrically connected to ground and a gate for receiving a corresponding said switching control signal, said field effect transistor, when conducting thereby grounding said speaker.

3. A sound distribution system in accordance with claim 1 wherein said switching control signals are substantially square waves and said switching control signal generating means comprises:

pulse responsive means responsive to a train of pulses applied thereto for sequentially generating first and second subtrains of pulses from alternate pulses in said train; and

square wave generating means-responsive to said subtrains of pulses for generating said plurality of trains of switching signals.

4. A sound distribution system in accordance with claim 3 wherein said switching control signal generating means further comprises oscillator means connectable to the input of said pulse responsive means for generating a train of timed pulses, said oscillator means comprising a variable frequency oscillator which is adjustable to provide a variable cycle frequency.

5. A sound distribution system in accordance with claim 4 which is completely electronic and further comprising means for continuously varying the output frequency of said variable frequency oscillator.

6. A sound distribution system in accordance with claim 3 wherein said switching signal generating means further comprises a frequency dividing means for dividing the frequency of said train of timed pulses in half such that one pulse is generated for every two pulses in said train of timed pulses, and means for selectively connecting said dividing means between said oscillator and said signal generating means.

7. A sound distribution system in accordance with claim 3 wherein each said control means comprises an electronic switch having a conducting and nonconducting state for, in the conducting state, selectively coupling said one signal train to said corresponding switch means, each said electronic switch being turned on by the leading edge of the switching signal signal in said further signal train, said further signal train containing the next switching control signal in sequence so as to provide a phase delay in the switching signal equal to the phase difference between successive signal trains.

8. A sound distribution system in accordance with claim 7 and further comprising wave shaping means for rounding off the leading and trailing edges of said phase delayed square waves thereby permitting a gradual operation of each of said switch means and consequently a gradual actuation of the corresponding said speaker.

9. An electronic system for cyclically distributing a sound input signal to a plurality of outputs, said system comprising:

an input for receiving the sound input signal;

a plurality of output terminals;

means for connecting said sound receiving input in parallel to each of said output terminals, including means for preventing the grounding of each output terminal upon the grounding of any other said output terminal;

a plurality of switch means individual to said output terminals, each switch means connected in parallel across said output terminal and between said preventing means and said output terminals for normally grounding said terminal and, in response to a switching control signal ,for undergrounding said terminal; and

means connected to said switch means for generating a plurality of trains of said switching control signals, equal in number to the number of said output terminals which differ in phase such that the switching control signals from the individual trains are presented sequentially to individual of said switch means so that said switch means are cyclically actuated to cause sequential undergrounding of said output terminals.

10. An electronic system in accordance with claim 9 wherein each said switch means comprises a field effect transistor electrically connected in parallel across said output terminal, said field effect transistor having a source electrically connected between said preventing means and said output terminal, a drain electrically connected to ground and a gate for receiving a corresponding said switching control signal, said field effect transistor when conducting thereby grounding said output terminal and, when actuated in response to said switching control signal, ungrounding said output terminal. I

11. An electronic system in accordance with claim 9 wherein said switching control signals are substantially square waves and said switching control signal generating means comprises:

pulse responsive means responsive to a train of pulses applied thereto for sequentially generating first and second subtrains of pulses from alternate pulses in said train;.and

square wave generating means responsive to said subtrains of pulses for generating said plurality of trains of switching signals.

12. An electronic system in accordance with claim 11 wherein said switching control signal generating means further comprises oscillator means connectable to the input of said pulse responsive means for generating a train of timed pulses, said oscillator means comprising a variable frequency oscillator which is adjustable to provide a variable cycle frequency.

13. An electronic system in accordance with claim 12 which is completely electronic and further comprising means for continuously varying the output frequency of said variable frequency oscillator.

14. An electronic system in accordance with claim 11 wherein said switching signal generating means further comprises frequency dividing means for dividing the frequency of said train of timed pulses in half such that one pulse is generated for every two pulses in said train of timed pulses, and means for selectively connecting said dividing means between said oscillator and said signal generating means.

15. An electronic system in accordance with claim 11 wherein each said control means comprises an electronic switch having a conducting and non-conducting state for, in the conducting state, selectively coupling said one. signal train to said corresponding switch means, each said electronic switch being turned on by the leading edge of the switching signal signal in said further signal train, said further signal train containing the next switching control signal in sequence so as to provide a phase delay in the switching signal equal to the phase difference between successive signal trains.

16. An electronic system in accordance with claim 15 further comprising wave shaping means for rounding off the leading and trailing edges of said phase delayed square waves thereby permitting a gradual operation of each of said switch means and consequently a gradual grounding of the said corresponding speaker.

17. An electronic apparatus for cyclically distributing a plurality of sound input signals to a plurality of sound outputs, said apparatus comprising:

a plurality of sound distributions devices, each sound distribution device comprising:

means for receiving a sound input signal;

a plurality of sound output terminals;

first means for connecting said sound input means in parallel to each of said sound output terminals, including means for preventing the grounding of each sound output terminal when any other sound output terminal is grounded;

a plurality of signal responsive switch means equal in number to the number of said output terminals and connected in parallel between said preventing means and said sound output terminal, for normally grounding a corresponding output terminal, each switch means responsive to a signal for undergrounding a corresponding said sound output terminal; means for generating a plurality of trains of switching signals differing in phase, whereby the generation of a first signal to the generation of a second signal within any signal train defines a cycle and the signal trains are generated such that the switching signals from the individual signal trains are presented sequentially within one cycle to a corresponding said switch means, the number of signal trains being equal to the number of sound output terminals; and

second means for connecting each said switching signal generating means to said corresponding switch means such that said switching signals sequentially actuate said corresponding switch means thereby producing the cyclic distribution of the sound input signal to said plurality of sound output terminals;

said apparatus further comprising a mixer means for mixing a plurality of sound input signals and for providing a plurality of sound output signals, said mixer means comprising a plurality of channels whereby each channel mixes a plurality of input signals and provides one output channel; and

further means for connecting at least one of said sound output terminals of each said sound distribution device to the same one of said channels in said mixer means.

18. An electronic apparatus in accordance with claim 17 wherein each said sound distribution device further comprises means for synchronizing the generation of said plurality of signal trains with the generation of said plurality of signal trains of at least one other sound distribution device, said further connecting means comprises a plurality of sets of conductors, each conductor set connecting a corresponding said sound distribution device to said mixer means such that each sound output terminal corresponding to the same phase signal train is connected to the same one of said channels of said mixer means.

Claims

1. A sound distribution system for cyclically distributing sound radiation in a plurality of different directions comprising: a plurality of speakers located so as to define the perimeter of a listening area; an input for receiving an electrical input signal corresponding to a sound signal; means for connecting said input in parallel with said plurality of speakers; a plurality of switch means, individual to said speakers, for selectively actuating a corresponding said speaker responsive to a switching control signal; means connected to said switch means for generating a plurality of trains of said switching control signals, equal in number to the number of said speakers, which differ in phase such that the switching control signals from the individual trains are presented sequentially to individUal of said switch means so that said switch means are cyclically actuated to cause sequential actuating of said speakers and hence produce a cyclical distribution of sound radiation from said plurality of speakers; and control means individual to said switch means and coupled to said generating means for selectively coupling one of said trains of switching signals to a corresponding said switch means, said control means being operably responsive to switching signals from a further of said trains of switching signals generated by said generating means.

3. A sound distribution system in accordance with claim 1 wherein said switching control signals are substantially square waves and said switching control signal generating means comprises: pulse responsive means responsive to a train of pulses applied thereto for sequentially generating first and second subtrains of pulses from alternate pulses in said train; and square wave generating means responsive to said subtrains of pulses for generating said plurality of trains of switching signals.

7. A sound distribution system in accordance with claim 3 wherein each said control means comprises an electronic switch having a conducting and non-conducting state for, in the conducting state, selectively coupling said one signal train to said corresponding switch means, each said electronic switch being turned on by the leading edge of the switching signal signal in said further signal train, said further signal train containing the next switching control signal in sequence so as to provide a phase delay in the switching signal equal to the phase difference between successive signal trains.

9. An electronic system for cyclically distributing a sound input signal to a plurality of outputs, said system comprising: an input for receiving the sound input signal; a plurality of output terminals; means for connecting said sound receiving input in parallel to each of said oUtput terminals, including means for preventing the grounding of each output terminal upon the grounding of any other said output terminal; a plurality of switch means individual to said output terminals, each switch means connected in parallel across said output terminal and between said preventing means and said output terminals for normally grounding said terminal and, in response to a switching control signal for undergrounding said terminal; and means connected to said switch means for generating a plurality of trains of said switching control signals, equal in number to the number of said output terminals which differ in phase such that the switching control signals from the individual trains are presented sequentially to individual of said switch means so that said switch means are cyclically actuated to cause sequential undergrounding of said output terminals.

10. An electronic system in accordance with claim 9 wherein each said switch means comprises a field effect transistor electrically connected in parallel across said output terminal, said field effect transistor having a source electrically connected between said preventing means and said output terminal, a drain electrically connected to ground and a gate for receiving a corresponding said switching control signal, said field effect transistor when conducting thereby grounding said output terminal and, when actuated in response to said switching control signal, ungrounding said output terminal.

11. An electronic system in accordance with claim 9 wherein said switching control signals are substantially square waves and said switching control signal generating means comprises: pulse responsive means responsive to a train of pulses applied thereto for sequentially generating first and second subtrains of pulses from alternate pulses in said train; and square wave generating means responsive to said subtrains of pulses for generating said plurality of trains of switching signals.

15. An electronic system in accordance with claim 11 wherein each said control means comprises an electronic switch having a conducting and non-conducting state for, in the conducting state, selectively coupling said one signal train to said corresponding switch means, each said electronic switch being turned on by the leading edge of the switching signal signal in said further signal train, said further signal train containing the next switching control signal in sequence so as to provide a phase delay in the switching signal equal to the phase difference between successive signal trains.

17. An electronic apparatus for cyclically distributing a plurality of sound input signals to a plurality of sound outputs, said Apparatus comprising: a plurality of sound distributions devices, each sound distribution device comprising: means for receiving a sound input signal; a plurality of sound output terminals; first means for connecting said sound input means in parallel to each of said sound output terminals, including means for preventing the grounding of each sound output terminal when any other sound output terminal is grounded; a plurality of signal responsive switch means equal in number to the number of said output terminals and connected in parallel between said preventing means and said sound output terminal, for normally grounding a corresponding output terminal, each switch means responsive to a signal for undergrounding a corresponding said sound output terminal; means for generating a plurality of trains of switching signals differing in phase, whereby the generation of a first signal to the generation of a second signal within any signal train defines a cycle and the signal trains are generated such that the switching signals from the individual signal trains are presented sequentially within one cycle to a corresponding said switch means, the number of signal trains being equal to the number of sound output terminals; and second means for connecting each said switching signal generating means to said corresponding switch means such that said switching signals sequentially actuate said corresponding switch means thereby producing the cyclic distribution of the sound input signal to said plurality of sound output terminals; said apparatus further comprising a mixer means for mixing a plurality of sound input signals and for providing a plurality of sound output signals, said mixer means comprising a plurality of channels whereby each channel mixes a plurality of input signals and provides one output channel; and further means for connecting at least one of said sound output terminals of each said sound distribution device to the same one of said channels in said mixer means.