EP1967036A2

EP1967036A2 - Bi-planar loudspeaker system with time-phased audio output

Info

Publication number: EP1967036A2
Application number: EP06848340A
Authority: EP
Inventors: Francis Allen Miller
Original assignee: Gaki Audio LLC
Current assignee: Gaki Audio LLC
Priority date: 2005-12-30
Filing date: 2006-12-29
Publication date: 2008-09-10
Also published as: WO2007079225A3; JP2009532921A; KR20080082663A; CN101444110B; WO2007079225A2; CN101444110A

Abstract

The present invention uses a system of three loudspeakers to achieve realistic stereophonic sound reproduction. The method uses a single enclosure for the left and right speakers positioned in front in a parallel plane, with a wedge shaped enclosure with the wedge affixed at the center of the single enclosure, and containing the third speaker positioned in parallel with the single enclosure containing the left and right speakers. The invention incorporates electronic circuitry to process the left and right audio input signals. The left and right channel signals are reduced to either channel, then summed and time- delayed to the center channel speaker. The wedge shaped enclosure interrupts the usual overlap of the left and right channels and fills this area with the specially derived center channel signal, such that the listener perceives a wider sound image space.

Description

TITLE

Bi-Planar Loudspeaker System With Time-Phased Audio Output

CROSS-REFERENCE TO RELATED APPLICATIONS

None

FEDERALLY SPONSORED RESEARCH

None

SEQUENCE LISTING OR PROGRAM None

BACKGROUND OF THE INVENTION

1. Field of the invention.

This invention deals with reproducing stereophonic sound realistically and dramatically through specially placed loudspeakers with a time-phased center channel derived from the two input channels.

2. Prior Art

The prior art for stereo loudspeaker systems is dominated by the use of two separate loudspeaker enclosures. One speaker enclosure is placed to the right of the listener's area. The other is placed symmetrically to the left of the listener's area. A listener at any point within the listening area that is equidistant from the two speaker enclosures will perceive a reasonably accurate stereo image.

The left channel information will appear to originate from the left speaker. The right channel information will appear to come from the right speaker. Center channel information will appear to come from a point located between the left and right speakers. Likewise, sounds recorded to appear just to the right or left of center will also be accurately perceived directionally.

If the listener is not at a point equidistant from the two speaker systems, i.e. not in the center between the two, this high degree of center-channel positional definition is lost. In this case, left sounds still appear to come from the left speaker system. Right sounds still appear to come from the right speaker system. But in the center channel information no longer appears to come from the position between the two speaker systems. Thus, without a highly defined center position, the entire stereophonic image is degraded significantly.

The cause of this loss of center channel position information is a relative time shift caused by a difference in distance to the listener from the left and right speaker systems respectively. Acoustic waves propagate at the velocity of Mach 1: or 334 meters per second. This value is usually considered constant, although changes in temperature, atmospheric pressure, and humidity can affect the velocity slightly. In any event, the propagation velocity will be the same for two sets of speakers sharing the same space. Although center channel information is applied to both speakers simultaneously, acoustic waves from the speakers that are closest will arrive at the listener's ears first. Acoustic waves from the speaker system farther from the listener will arrive later, delayed by the additional distance they are required to travel before they reach the listener's ears.

For instance, a listener is at a certain position in the listening environment which will be called "P" in this example. Position "P" is located approximately 167 cm (5.57 feet) from the left speaker(s) and 200.4 cm (6.68 feet) from the right speaker(s). Acoustic waves from the left speaker will arrive at the listening position (P) 5 milliseconds after being produced by the speaker. Acoustic waves from the right sρeaker(s) will arrive at position "P" 6 milliseconds after being produced by the right speaker, yielding an arrival time difference of one millisecond, which will be called "T". Audio information applied simultaneously to both left and right speakers (SIN theta) will combine at a listening position (P) as a composite of the sum of both signals: (SIN theta) from the left speaker(s) and (SIN theta + T) from the right speaker(s). The net acoustic energy perceived at position P will be (SIN theta) + (SIN theta +T). Acoustic energy from two sources can combine constructively, if it is in phase, and produce net energy larger than either component. It can also combine destructively, if the two sources are out of phase, and they can cancel each other. This depends on the relative phase difference produced by the time shift (T). The French mathematician J.D J. Fourier laid out the equations by which one may calculate the relative phase for any frequency for a fixed time shift (T). For the example given, where T= 1 millisecond, null frequencies would occur at 500HZ, 1.5KHZ₅ 2.5 KHZ, 3.5 KHZ, 4.5 KHZ, 6.5 KHZ, 7.5 KHZ, 8.5 KHZ, 9.5 KHZ, 10.5 KHZ, 11.5 KHZ, 12.5 KHZ and so on. This is known as the "comb effect", from the regular spacing of the null frequencies, and is a common problem in dual-enclosure stereo systems.

To compound the situation, a human being listens with two ears located approximately 12 centimeters apart. This means that perception actually happens at two discreet points in the listening environment. Each individual ear has a different response transform, which further alters the frequencies perceived by the listener. One of the ways human ears localize sounds is by comparing the arrival times of a sound between one ear and another. When the center channel information in a conventional dual speaker stereo system no longer strikes the listener's two ears simultaneously, the listener is no longer able to localize the direction of the center channel information and the stereo image collapses.

Audiophiles refer to the area of the listener's environment equidistant from the two speaker systems as the "Sweet Spot^". With a typical system set up in a room, the Sweet Spot is usually only large enough to accommodate one person. A common example would be a listening situation involving three people seated side by side on a couch; if the person in the center seat is in the Sweet Spot, enjoying an accurate stereophonic image, the people seated on the left or the right generally will not perceive stereo with any degree of accuracy. United States patent number 4,058,675, (November 15, 1977), "Loudspeaker System for use in a Stereophonic Sound Reproduction System" discloses a loudspeaker system, a main speaker adapted to be driven by audio input signal and radiate acoustic energies toward a listener for stereophonic reproduction, and a sub-speaker adapted to be driven by the input signal and radiate out-of-phase acoustic energies which are smaller in magnitude than the acoustic energies provided by the main speaker and reach the listener with a time delay.

United States patent number 6,069,962, (May 30, 2000), "Point Source Speaker System" was another attempt to expand the Sweet Spot. This patent discloses an arrangement using a dual voice-coil bass-rnidrange speaker with two high frequency speakers mounted coaxially at +/- 45 degrees off the center axis of the bass-midrange speaker. This system produces only a slight separation at high frequencies. Midrange and low frequency acoustic energy is produced monophonically by the single-cone speaker.

United States patent number 6,169,812 Bl, (January 2, 2001), "Point Source Speaker System" was an attempt to expand the Sweet Spot. The essence of this patent is to situate three speakers in a single enclosure such that the axes of the acoustic waves produced by each of the speakers have a common point of origin. The patent also teaches an alteration of the acoustic wave forms. The axis of each speaker to the one adjacent is set at 90 degrees. The left speaker is fed with a difference signal (Left minus Right). The right speaker is fed with a difference signal (Right minus Left). The center speaker is fed with a sum signal (Left plus Right). This arrangement produces a very distinctly located center channel image. However, separation is lost at the outer limits of the Sweet Spot due to the 180-degree placement of the axes of the left and right speakers.

United States patent number 5,557,680 (September, 1996) "Loudspeaker System for Producing Multiple Sound Images Within a Listening Area from Dual Source Locations" takes the approach of creating a center channel audio image derived from the two input left and right channels, and then positions two cabinets on either side and at an angle to the listener. The two cabinets house the speakers for the left/right channel inputs along with a speaker for the derived center channel. This patent attempts to eliminate time phasing problems by placing the center channel speakers in the same enclosures with the left and right channel speakers, but the speakers occupy different axes.

United States patent number 5,426,702 (June, 1995) "System for Deriving a Center Channel Signal from an Adapted Weighted Combination of the Left and Right Channels in a Stereophonic Audio Signal", teaches a weighted calculation method for deriving a center channel audio image from both the left and right channel inputs. However, the patent does not teach how to place the speakers to get an improved sweet spot from this method.

United States patent number 5,610,986 (March, 1997) "Linear-Matrix Audio-Imaging System and Image Analyzer" teaches a method for deriving a center channel audio image from both the left and right channel inputs. The teachings do not take into account the time- phasing due to speaker placement, nor the time-phasing required on the center channel in order to synchronize the center channel with the right and left images.

BRIEF DESCRIPTION OF THE DRAWINGS 1. Figures

Figure 1 shows the single rectangular shaped enclosure from a frontal angle, consisting of three speakers implementing the invention, with a right and left speaker and the center speaker contained in the centered wedge that diverts the sound from both the right and left speaker

Figure 2 shows the single rectangular shaped enclosure from a top view with the two cavities for the left and right speakers along with the third speaker in the center wedge, and the acoustic wave propagation patterns are disclosed Figure 3 depicts the audio signal processing and major connections between the audio signal inputs and the processed audio signal outputs to the speakers ^k

Figure 4 shows the single rectangular shaped enclosure from a top view with the two cavities for the left and right speakers along with the third speaker in the center wedge

Figure 5 depicts the front view of the single enclosure in the rear and the wedge shaped enclosure in the front

Figure 6 depicts the angled view of the single enclosure in the rear and the wedge shaped enclosure in the front

Figure 7 depicts the prior art showing the acoustic waves produced by a legacy two speaker stereo loudspeaker system

Figure 8 depicts the sound image area and the acoustic waves produced by an embodiment of the present invention without the time-delay feature

Figure 9 depicts the prior art showing the acoustic waves and the sound image space using the prior art point source loudspeaker system

Figure 10 depicts the apparent sound image and the acoustic waves produced by the present invention

DETAILED DESCRIPTION PREFERRED EMBODIMENT

The present invention consists of a single rectangular shaped speaker enclosure 10 containing both the left 16 and right channel 18 speakers located in a common plane. The speakers are mounted side by side as close together as possible. A speaker for the center channel 20 is mounted in a wedge 12, in front of the two coplanar speakers in a parallel plane. The wedge 12 extending from the front of the rectangular shaped speaker enclosure 10 incorporating the center channel speaker 20 separates the left 16 and right 18 channel speakers and reflects some of their acoustical energy. A temporal-delay crossover network 82 splits the left channel audio output signal 40, the right channel audio output signal 70 and the center channel audio output signal 55 by frequency to feed high-range left channel tweeters 15, right channel tweeters 17 and center channel tweeters 19, along with mid-range and/or low range sub-woofer speakers 25, and also delays the center channel output 55, creating a broader waveform which gives a listener the illusion of a wide soundstage existing behind the speaker enclosures 10 and 12.

The reason the signal applied to the center channel power amplifier 50 is delayed is that the center speaker lies closer to a listener (seated directly in front of it) by the distance between the plane containing the center channel speaker 20 and the plane containing the left channel speaker 16 and the right channel speaker 18. Without the temporal delay to the center channel speaker 20, the listener would perceive the sound from the center channel speaker 20 well before the arrival of the sound from either the right channel speaker 18 or the left channel speaker 16. This temporal displacement produces a corresponding relative phase displacement, which can be calculated using J.D. J. Fourier's formulas.

The additional acoustic energy produced by the center channel speaker 20, which is (1/2 {L+R})₅ unbalances the total sum and difference energy as the perceived energy. The system's acoustic energy would then be L + R + (1/2 {L+R)). To compensate for this unbalance, the right channel audio input 60 signal and the left channel audio input 30 signal's are processed as set forth in the descriptive details of Figure 3.

The total acoustic energy in the system is now (R - { 1 /2 L}) + (L - { 1/2 R }) + ({ 1/2L} +{ 1/2R}) — L + R, which returns the acoustic energy to balance. A diagram of the spatial energy distribution produced by the embodiment of the invention described in the previous figures.

In particular, Figure 4 shows the points at which electrical energy is supplied to the three main speakers. The resulting acoustical energy as propagated into the listening area by the speakers is shown in Figure 2. If acoustic level measurements are made from the furthest left edge (Figure 2) of the left channel energy area 42 to the furthest right edge of the right channel energy area 72, it will soon be seen that the left acoustic energy is greatest at the leftmost edge. The right acoustic energy is greatest at the rightmost edge of the right channel energy area 72. At the leftmost edge of the left channel energy area 42, the right acoustic energy is null [(1/2 R from center channel speaker 20) + (-1/2 R from left channel speaker 16) = O].

At the exact center of the center channel energy area 52, the right acoustic energy is (1/4 R) and the left acoustic energy is (1/4 L). This is the point in the listening environment where the Left and Right energy is equal. At all points right of the center, the Right energy is greater than the Left energy. At all points left of center, the Left energy is greater than the Right energy. Using Figure 2, it is obvious that any point in the shadow has a specific ratio of Left and Right energy.

For instance, a listener's left ear is located at some point P(Left) in the shadow, and his right ear is located at a second point P(Right) in the shadow. Point P(Right) is 12 cm (the width of the average listener's head) closer to the right edge of the acoustical area than point P(Left). P(Left) is 12 cm. closer to the left edge of the acoustical area than P(Right). From this information we can deduce the following:

The left acoustic energy perceived by the ear at P(Left) will be greater than the left acoustic energy perceived by the right ear at P(Right). Likewise the right acoustic energy perceived by the right ear at P(Right) is greater than the right energy perceived by the left ear at P(Left). The right ear hears more right energy, and the left ear hears more left energy. Therefore, the right energy will be perceived as originating at a phantom point R(Q) to the right of the enclosure, and the left energy will appear to come from a phantom point L(Q) to the left of the enclosure. This set of conditions holds true for all sets of two points located anywhere in the propagated energy areas of the wedge. The stereo image will be perceived as long as the two points are not equidistant to the two edges of the propagated energy area.

A special case exists that doesn't produce the perception of stereo. If the listener's line of sight is perpendicular to the direction of the rectangular shaped speaker enclosure 10 the two ears (P {Left} and P {Right}) will both be equidistant from both edges of the acoustical energy area. Therefore, no difference in level will be perceived for the left or right signals. This listener will not perceive stereo.

REFERENCE NUMERALS

5 enclosure circuitry depicts the major components of the circuits necessary to process and connect the audio components within the speaker enclosure

7 tweeter speaker support wire or other type of support for tweeter speakers mounted in the center of each channel speaker

10 rectangular shaped speaker enclosure containing the right channel speaker, the left channel speaker, the enclosure circuitry and the means for accommodating the wedge containing the center speaker

11 enclosure partition internally separating the left cavity from the right cavity

12 wedge to deflect the right and left channel acoustic waves and to hold the center speaker

14 wedge attachment point for affixing the wedge to the center of the speaker enclosure

15 left channel tweeter speaker for transmitting the high range acoustic waves sent to the left channel

16 left channel speaker for transmitting the acoustic waves sent to the left speaker

17 right channel tweeter speaker for transmitting the high range acoustic waves sent to the right channel

18 right channel speaker for transmitting the acoustic waves sent to the right speaker

19 center channel tweeter speaker for transmitting the high range acoustic waves sent to the center channel

20 center channel speaker for transmitting the acoustic waves directed to the center speaker

21 enclosure face plane is the front plane of the enclosure in which the two speakers are placed 22 wedge left suppression surface coated with or made of a substance to minimize the reflection of high frequency acoustic waves

23 wedge right suppression surface coated with or made of a substance to minimize the reflection of high frequency acoustic waves

24 wedge face plane is the front plane of the wedge in which the center channel speaker is placed

25 sub-woofer speaker is the sub-woofer for transmitting the low range acoustic waves

26 right cavity is the opening on the right side of the speaker enclosure to accommodate the right channel speaker

28 left cavity is the opening on the left side of the speaker enclosure to accommodate the left channel speaker

30 left channel audio input is where the audio signal for the left channel is input to the enclosure

32 left channel power amplifier accepts the input signals and amplifies them to the left channel audio output

34 left channel conductor is the direct left audio channel conductor from the left channel audio input to the left channel power amplifier

36 left channel attenuator is a component, consisting of resistors R3 and R4, that is applied to the left channel audio signal to reduce the signal by one half

38 left channel conducer is the connector combined with the attenuator that connects the original left channel input signal, now attenuated, to the right channel output amplifier

40 left channel audio output is where the audio signal for the left channel is output to the left channel speaker

41 left channel high frequency audio output is where the high frequency portion of the audio signal for the left channel is output to the left channel tweeter 42 left channel energy area where the acoustic energy from the left channel speaker is propagated and deflected by the wedge

50 center channel power amplifier accepts the input signals and amplifies them to the center channel audio output

52 center channel energy area where the acoustic energy from the center channel speaker is propagated between the left and right energy areas

55 center channel audio output is where the audio signal for the center channel is output to the center channel speaker

56 center channel high frequency audio output is where the high frequency portion of the audio signal for the center channel is output to the center channel tweeter

58 center channel summing conductor is the connection between the summing junction and the time delay network

59 center channel timing delay conductor is the connection between the time delay network component and the center channel power amplifier

60 right channel audio input is where the audio signal for the right channel is input to the enclosure

62 right channel power amplifier accepts the input signals and amplifies them to the right channel audio output

64 right channel conductor is the direct right audio channel conductor from the right channel audio input to the right channel power amplifier

66 right channel attenuator is a component, consisting of resistors Rl and R2, that is applied to the right channel audio signal to reduce the signal by one half

68 right channel conducer is the connector combined with the attenuator that connects the original right channel input signal, now attenuated, to the left channel output amplifier

70 right channel audio output is where the audio signal for the right channel is output to the right channel speaker 71 right channel high frequency audio output is where the high frequency portion of the audio signal for the right channel is output to the right channel tweeter

72 right channel energy area where the acoustic energy from the right channel speaker is propagated and deflected by the wedge

80 summing junction component takes the left and right audio signals and sums them, such that the output is one half of the combined left and right signals

82 time delay network component takes a signal as input, usually from the summing junction, and the input signal is then time-delayed by a factor T

83 sound image space is the area/space where the listener perceives that the acoustic energy is coming from

84 combined energy area is the acoustic energy from the right, left, and center channel speakers is propagated

FIGURES

Figure 1 The rectangular shaped speaker enclosure 10 is a hollow block. An internal partition 11 separates the inside of the block into a left cavity 28 and a right cavity 26, providing separate chambers for the rearward projections of the left channel speaker 16 and the right channel speaker 18. A hollow wedge 12 is mounted between the two speakers with its apex touching the rectangular shaped speaker enclosure 10 at a wedge attachment point 14 equidistant between the left channel speaker 16 and the right channel speaker 18. A third speaker, the center channel speaker 20, is mounted in the base of the wedge 12. The wedge 12 is positioned so that the wedge face plane 24 is parallel with the enclosure face plane 28. The base of the wedge 12 is parallel with the base of the rectangular shaped speaker enclosure 10. The top of the wedge 12 is parallel with the top of the rectangular shaped speaker enclosure 10. The distance between the enclosure plane 28 and the wedge plane 24 is equal to the altitude of the triangular sides of the wedge 12. The wedge left suppression surface 22 facing the left channel speaker 16 and the wedge right suppression surface 23 facing the right channel speaker 18 are made of (or coated with) a substance to minimize, "suppress", the reflection of high frequency acoustic waves. This reduces high frequency "spatter".

Figure 2 Depicts the left channel energy area 42, the center channel energy area 52 and the right channel energy area 72 produced by the three speakers. The left channel speaker 16 mounted in the rectangular shaped speaker enclosure 10 produces the left channel energy area 42. The right channel speaker 18 mounted in the rectangular shaped speaker enclosure 10 produces the right channel energy area 72. The sub-woofer 25 is mounted at the bottom of the rectangular shaped speaker enclosure 10. The center channel speaker 20 mounted in the wedge 12 produces the center channel energy area 52. The right channel energy area 72 produced by the right channel speaker 18 is diverted from mixing with the left channel energy area 42 by the interference of the wedge right suppression surface 22 and the wedge left suppression surface 23. The interference of the wedge right suppression surface 23 substantially shifts the maximum propagation axis of the right channel speaker 18 to the right of the wedge 12. Likewise, interference of the wedge left suppression surface 22 substantially shifts the maximum propagation axis of the left channel speaker 16 to the left of the wedge 12. This diversion of the left channel speaker 16 and the right channel speaker 18 acoustic energies produces a lowered energy zone directly in front of the enclosure. This zone corresponds with the major propagation axis of the center channel speaker 20 and the resulting center channel energy area 52.

Figure 3 is a block diagram for the speaker enclosure circuitry 5 supplying electrical energy to the three main channel speakers: left channel 16, right channel 18, and center channel 20. In addition, the high frequency output for the left channel 41, the right channel 71 and the center channel 56 are output respectively to the left channel tweeter 15, the right channel tweeter 17 and the center channel tweeter 19. The right channel audio input 60 is supplied directly to the input of the right channel power amplifier 62 hy way of the right channel conductor 64. Likewise, the left channel audio input 30 is supplied directly to the positive (non-inverting) input of the left channel power amplifier 32 by way of the left channel conductor 34. The left channel audio input 30 and the right channel audio input 60 are summed by a summing junction 80 the output of which is one half of Left plus Right. This signal (1/2 {L+R}) is fed to the input of a time delay network 82, by way of the center channel summing conductor 58. The output of the time delay network 82 is (1/2 {L + R}) delayed by time delay factor T. This delayed signal is applied to the positive (non-inverting) input of the center channel power amplifier 50 by way of the center channel timing delay conductor 59. The right channel audio input 60 is applied to the right channel attenuator 66 consisting of resistors R3 and R4. The output of the right channel attenuator 66 is 1/2 R and is applied to the "-" (inverting) input of the left channel power amplifier 32 by way of the right channel conducer 68. This changes the output of the left channel power amplifier 32 from L to L - (1/2 R). Likewise, the left channel audio input 30 is applied to the left channel attenuator 36 consisting of resistors R3 and R4. The output of the left channel attenuator 36 is 1/2 L, and is applied to the "-" (inverting) input of the right channel power amplifier 62 by way of the left channel conducer 38. This changes the output of the right channel power amplifier 62 from R to R - (1/2 L).

Figure 4 depicts the rectangular shaped speaker enclosure 10 from a top view with the left cavity 28 housing the left channel speaker 16, the right cavity 26 housing the right channel speaker 18 the enclosure circuitry 5 as a block diagram (described in detail in Figure 3), and the wedge 12, housing the center channel speaker 20, affixed to the speaker enclosure 10 at the wedge insertion point 14. The electrical inputs and outputs to the enclosure circuitry 5 are shown, with the left channel input 30, the right channel input 60, the left channel audio output 40, the right channel audio output 70 and the center channel audio output 55. Figure 5 depicts the rectangular shaped speaker enclosure 10 from a front view with the left cavity 28 housing the left channel speaker 16, and the left channel tweeter speaker 15, the right cavity 26 housing the right channel speaker 18, and the right channel tweeter speaker 17, and the wedge 12, showing the wedge face plane 24, and housing the center channel speaker 20, with the center channel tweeter speaker 19. Each of the tweeter speakers 15, 17 and 19 are supported in the center of the respective left channel speakerl6, right channel speaker 18 and center channel speaker 20 by two perpendicular cross supports 7 on the face of each of the respective speaker enclosures 28, 26 and 24. The sub-woofer speaker 25 is shown in profile, projecting from the base of the rectangular shaped speaker enclosure 10.

Figure 6 depicts the rectangular shaped speaker enclosure 10 from an angled perspective with the left cavity 28 housing the left channel speaker 16, and the left channel tweeter speaker 15, the right cavity 26 housing the right channel speaker 18, and the right channel tweeter speaker 17 (not shown), and the wedge 12, showing the wedge face plane 24, and housing the center channel speaker 20, with the center channel tweeter speaker 19, affixed to the speaker enclosure 10 at the wedge insertion point 14. The wedge left suppression surface 22 facing the left channel speaker 16. The sub- woofer speaker 25 is shown in profile, projecting from the base of the rectangular shaped speaker enclosure 10.

Figure 7 depicts the prior art of a legacy two enclosure stereo system with left channel energy area 42, right channel energy area 72 and the perceived sound image space 83 as experienced by the listener.

Figure 8 depicts the Bi-planar Single Enclosure without the time delay network 82 engaged. This figure shows the perceived image space 83 as experienced by the listener. The rectangular shaped speaker enclosure 10 is depicted with the left channel speaker 16, the right channel speaker 18 and the center channel speaker 20 enclosed in the wedge 12. Figure 9 depicts the prior art Point Source System with the perceived image space 83 as experienced by the listener. The single speaker enclosure and the combined energy area that is produced by that technology.

Figure 10 depicts the Bi-planar Single Enclosure with the time delay network 82 engaged. This figure shows the perceived image space 83 as experienced by the listener. The rectangular shaped speaker enclosure 10 is depicted with the left channel speaker 16, the right channel speaker 18 and the center channel speaker 20 enclosed in the wedge 12. The figure also depicts the combined energy area 84 emanating from the right, left, and center channel speakers with the time delay network 82 (not shown) engaged.

Claims

CLAIMSI claim,

1. An audio output acoustic energy system comprising: input means, for receiving first and second channel audio input signals, said first and second channels being designated respectively, the left audio input signal channel (L) and the right audio input signal channel (R); first, second and third audio output channels for producing first, second and third audio output signals; three loudspeakers, each of the same size and input/output specifications, each capable of receiving said first, second and third audio output signals and producing acoustic energy output therefrom; an electrical circuit incorporating deriving means coupled to said input means, for deriving said first audio output signal on the left channel output as L-{1/2R}, for deriving said second audio output signal on the right channel output as R-{1/2L}, and for deriving said third audio output signal on the center channel output as ^{L+R} - T where T is a temporal time delay applied to balance the third output channel with the first and second output channels; a single loudspeaker enclosure divided into two cavities in which each of two of said loudspeakers are placed symmetrically, in the front of each cavity, close together, in the same plane, facing the listener; and a wedge shaped loudspeaker enclosure affixed at the apex of the wedge to the center of said single loudspeaker enclosure between the two single loudspeaker enclosure cavities, the front of the wedge shaped loudspeaker enclosure being the same width as each , of the two single loudspeaker enclosure cavities, with the depth from the front of the wedge shaped loudspeaker enclosure to the apex of the wedge being the same depth as that of the cavities in said single loudspeaker enclosure, with the angled sides of the wedge shaped loudspeaker enclosure incorporating acoustic energy suppression means, with the third loudspeaker being placed in the wedge shaped loudspeaker enclosure in a parallel plane with the two speakers in the single loudspeaker enclosure, in the front portion of said wedge shaped loudspeaker enclosure, facing the listener.

2. An audio output acoustic energy system according to claim 1, in which said single loudspeaker enclosure and said wedge shaped loudspeaker enclosure include means for deriving multiple feed high-range, mid-range, and/or low range audio output signal channels and specialized loudspeakers for outputting each audio output frequency range on respective left, right and center channels.

3. An audio output acoustic energy system according to claim 1, in which said single loudspeaker enclosure and said wedge shaped loudspeaker enclosure are both incorporated into a single enclosure.

4. An audio output acoustic energy system according to claim 1, in which said single loudspeaker enclosure is divided into two separate enclosures wherein said wedge shaped loudspeaker enclosure is equidistant between said two separate enclosures wherein the loudspeakers affixed within said two separate enclosures and said wedge shaped enclosure are in parallel planes with each other.

5. An audio output acoustic energy system according to claim 1, in which said three loudspeakers are supplemented with sub-woofer and tweeter output loudspeakers.