Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R5/00—Stereophonic arrangements
  • H04R5/02—Spatial or constructional arrangements of loudspeakers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R5/00—Stereophonic arrangements
  • H04R5/04—Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S3/00—Systems employing more than two channels, e.g. quadraphonic
  • H04S3/002—Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
  • H04R1/34—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means
  • H04R1/345—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means for loudspeakers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R2205/00—Details of stereophonic arrangements covered by H04R5/00 but not provided for in any of its subgroups
  • H04R2205/022—Plurality of transducers corresponding to a plurality of sound channels in each earpiece of headphones or in a single enclosure
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S2400/00—Details of stereophonic systems covered by H04S but not provided for in its groups
  • H04S2400/05—Generation or adaptation of centre channel in multi-channel audio systems
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S5/00—Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation 

Definitions

• 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.
• 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.
• 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.
• 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.
• 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 s ⁇ eaker(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 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).
• T time shift
• 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 " .
• 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.
• 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
• 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.
• 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.
• 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.
• 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.
• 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).
• 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).
• 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.
• 5 enclosure circuitry depicts the major components of the circuits necessary to process and connect the audio components within the speaker enclosure
• center channel speaker for transmitting the acoustic waves directed to the center speaker
• 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
• 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
• 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
• 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
• 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
• center channel power amplifier accepts the input signals and amplifies them to the center channel audio output
• 55 center channel audio output is where the audio signal for the center channel is output to the center channel speaker
• 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
• center channel summing conductor is the connection between the summing junction and the time delay network
• 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
• 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
• 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
• right channel audio output is where the audio signal for the right channel is output to the right channel speaker
• 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
• 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
• 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
• sound image space is the area/space where the listener perceives that the acoustic energy is coming from
• 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.
• 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.
• 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.
• 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.
• the left channel power amplifier 32 This changes the output of the left channel power amplifier 32 from L to L - (1/2 R).
• 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.

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• 2006
  • 2006-12-29 EP EP06848340A patent/EP1967036A2/de not_active Withdrawn
  • 2006-12-29 WO PCT/US2006/049577 patent/WO2007079225A2/en active Application Filing
  • 2006-12-29 CN CN200680049988.4A patent/CN101444110B/zh not_active Expired - Fee Related
  • 2006-12-29 JP JP2008548769A patent/JP2009532921A/ja active Pending
  • 2006-12-29 KR KR1020087015997A patent/KR20080082663A/ko not_active Application Discontinuation

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