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DESCRIPTION JP2016516355

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DESCRIPTION JP2016516355
Abstract An audio receiver is described which performs crosstalk cancellation using a
loudspeaker array. The audio receiver detects the position of the listener in the room and
processes one audio program content output through the speaker array using one or more beam
pattern matrices. The beam pattern matrix is generated by one or more constraints. As a
constraint, increasing the right channel and decreasing the left channel in the listener's right ear,
increasing the left channel and decreasing the right channel in the listener's left ear And reducing
speech in all other areas of the room. These constraints cause the audio receiver to emit sound
primarily towards the listener, not to other areas of the room, so that crosstalk cancellation is
achieved with minimal impact of fluctuations on the room's frequency response. Do. Other
embodiments are also described.
Robust crosstalk cancellation with speaker array
[0001]
RELATED APPLICATIONS This application claims the benefit of the earlier filing date of US
Provisional Application No. 61 / 782,287, filed March 14, 2013.
[0002]
An audio receiver is described that performs crosstalk cancellation by achieving one or more
constraints using a speaker array.
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Other embodiments are also described.
[0003]
A single loudspeaker can produce sound on both ears of the listener. For example, the
loudspeaker on the left side of the listener still produces some sound on the listener's right ear.
The purpose of the crosstalk canceller is to be able to produce sound in one of the listener's ears
without producing sound in the other ear. This separation allows any sound to be produced in
one ear without spilling to the other ear. Controlling the sound independently at each ear can be
used to give the impression that the sound comes from a distance from the loudspeaker.
[0004]
In principle, the crosstalk canceller only needs two speakers (ie two degrees of freedom) to
control the sound separately with two ears. Many crosstalk cancelers control the sound in the
listener's ear by compensating for the effects (usually known as head-related transfer functions
(HRTFs)) generated by the sound that diffracts around the listener's head Do. Assuming that the
right audio input channel is d R and the left audio input channel is d L, the crosstalk canceller
can be expressed as:
[0005]
In this equation, the transfer function H of the listener's head due to the sound coming from the
loudspeaker is compensated by the inverse function H <-1> of the transfer function and the right
and left ears of the listener respectively have the right output channel f R And the left output
channel f L. Many crosstalk cancelers that use only two speakers suffer from poor conditioning
at some frequencies. For example, the loudspeakers of these systems need to be driven with large
signals to achieve crosstalk cancellation, and are very sensitive to changes from ideal conditions.
In other words, if the system is designed with an estimated transfer function H (representing the
propagation of sound from the loudspeaker to the listener's ear), a small change in H can cause
the crosstalk canceller to stop working There is sex. One example of this is that although the
transfer function H is measured in an anechoic environment (ie without acoustic reflections), it is
then the case of a real room with a large number of reflections .
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[0006]
One embodiment of the invention is an audio receiver that performs crosstalk cancellation using
a speaker array having a plurality of transducers. The audio receiver detects the position of the
listener in the room or listening area, and then processes a piece of audio program content using
one or more beam pattern matrices corresponding to the positions at which the listener was
detected. Output by the speaker array. Beam pattern matrices correspond to particular audio
frequencies and are generated according to one or more constraints. Then, it can be set in
advance to the audio receiver. The following can be mentioned as this constraint condition. (1)
Maximizing / increasing the left channel of a piece of audio program content with the listener's
left ear, and / or minimizing / reducing the right channel, (2) the listener's Maximizing /
enhancing the right channel and minimizing / reducing the left channel with the right ear, and
(3) minimizing the speech in all other areas of the room Making / reducing. Due to these
limitations, the audio receiver will mainly emit sound towards the listener. By emitting sound
towards the listener rather than in other areas of the room, crosstalk cancellation is achieved
with minimal or reduced impact of changes to the room's frequency response.
[0007]
The above summary does not provide an exhaustive list of all aspects of the invention. The
present invention includes all possible systems and methods from all suitable combinations of
the various aspects summarized above, as well as those disclosed in the following detailed
description, in particular the application. It is believed that what is pointed out in the claims is
included. Such combinations have certain advantages that are not specifically described in the
above summary.
[0008]
Embodiments of the invention are illustrated by way of example and not by way of limitation in
the figures of the accompanying drawings in which like references indicate similar elements. It
should be noted that references in the present disclosure to the "an" or "one" embodiments of the
present invention are not necessarily to the same embodiment and that they mean at least one.
[0009]
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1 illustrates a room or listening area with an audio system according to one embodiment. 7
illustrates a room or listening area with an audio system according to another embodiment. 3
illustrates a loudspeaker array housed in a single cabinet according to one embodiment. 7
illustrates a loudspeaker array housed in a single cabinet according to another embodiment. FIG.
6 shows a functional block diagram of an audio receiver according to one embodiment and some
constituent hardware components. Show the listener at the first place in the room. Show the
listener at the second place in the room. FIG. 1 illustrates a system for generating a beam pattern
matrix for a single listener using a set of microphones according to one embodiment. FIG. 1
illustrates a system for generating beam pattern matrices for multiple listeners using a set of
microphones according to one embodiment. FIG. 5B illustrates a method of generating a beam
pattern matrix using the microphone configurations shown in FIGS. 5A and 5B according to one
embodiment.
[0010]
Hereinafter, some embodiments will be described with reference to the attached drawings.
Although many details are described, it will be appreciated that some embodiments of the
present invention may be practiced without these details. In other instances, well known circuits,
structures and techniques have not been shown in detail in order not to obscure the
understanding of the present description.
[0011]
FIG. 1A shows an audio system 1 comprising an external sound source 2, an audio receiver 3 and
one or more loudspeaker arrays 4. The audio system 1 outputs the audio program content to the
room or listening area 7 where the intended listener 6 is located. The listener 6 customarily sits
at the target position where the audio system 1 mainly orients or targets. The target position is
usually at the center of the room 7 but may be any designated area of the room 7.
[0012]
External sound source 2 can be any device capable of transmitting one or more audio streams
(representing audio program content) to audio receiver 3 for processing. For example, the
external sound source 2 of the system 1 of FIG. 1A transmits one or more audio streams
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(representing audio program content) to the audio receiver 3 for processing either via a wired or
wireless connection It is a laptop computer. In another embodiment, the external sound source 2
may instead be one or more desktop computers, tablet computers, mobile devices (e.g. cell
phones or mobile music players), and remote media servers (e.g. internet stream music) Or a
movie service).
[0013]
As shown in FIG. 1A, the components of the audio system 1 are distributed and housed in
different units. In contrast, as shown in the embodiment of the audio system 1 of FIG. 1B, the
audio receiver 3 is integrated into the loudspeaker array 4 to provide a stand-alone unit. In this
embodiment, the loudspeaker array 4 receives one or more audio streams representing audio
program content directly from the external sound source 2 by either a wired or wireless
connection.
[0014]
Although described as receiving an audio stream from the external sound source 2, the audio
receiver 3 can access a storage medium with an audio stream stored locally. In this embodiment,
the audio receiver 3 reads the audio stream for processing from a local storage medium without
cooperation with the external sound source 2.
[0015]
As described in more detail below, the audio receiver 3 may be any device type or set of devices
for processing audio streams and driving one or more loudspeaker arrays 4. For example, the
audio receiver 3 can be a laptop computer, a desktop computer, a tablet computer, a mobile
device, or a home theater audio receiver.
[0016]
Referring now to the loudspeaker array 4, FIG. 2A shows a loudspeaker array 4 having a plurality
of transducers 5 housed in a single cabinet 6. In this example, the speaker array 4 has 32
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different transducers 5 uniformly aligned in eight rows and four columns in the cabinet 6. In
another embodiment, different numbers of transducers 5 can be used with uniform or nonuniform spacing. For example, as shown in FIG. 2B, ten transducers 5 can be aligned in a cabinet
6 to form a soundbar-style speaker array 4. Although shown aligned in a flat plane or in a
straight line, the transducers 5 can be aligned in a curved fashion along an arc.
[0017]
The transducer 5 can be any combination of full range driver, mid range driver, subwoofer,
woofer and tweeter. Each of the transducers 5 can use a cone that is connected to a rigid basket
or frame via a lightweight diaphragm or flexible suspension. The suspension limits axial
movement of the wire coil (e.g., voice coil) through the cylindrical magnetic gap. When an
electrical audio signal is applied to the voice coil, the current in the voice coil generates a
magnetic field to form a variable electromagnet. The magnetic system of the coil and transducer
5 interact to generate mechanical force that moves the coil (and hence the cone coupled to it)
back and forth. This reproduces the sound under control of an applied electrical audio signal
coming from a source (e.g. a signal processor, a computer and an audio receiver). Although
described herein as having multiple transducers 5 housed in a single cabinet 6, in another
embodiment, the speaker array 4 comprises a single transducer 5 housed in a cabinet 6 be able
to. In these embodiments, the speaker array 4 is a stand alone loudspeaker.
[0018]
Each transducer 5 can be individually driven separately to generate sound in response to
different individual audio signals. By allowing the transducers 5 of the loudspeaker array 4 to be
driven separately and individually according to different parameters and settings (including
delays and energy levels), the loudspeaker array 4 can be configured with a large number of
directivity patterns. Can occur. This directional pattern simulates or more fully represents the
respective channels of audio program content to be played back to the listener 6. For example,
beam patterns of different widths and directivity can be emitted by the speaker array 4.
[0019]
As shown in FIG. 1A, the speaker array 4 can include wires or conduits that connect to the audio
receiver 3. For example, each speaker array 4 can include two wiring points, and the audio
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receiver 3 can include complementary wiring points. The wiring points can be coupling posts or
spring clips behind the speaker array 4 and the audio receiver 3 respectively. Electrical wires are
separately wound or otherwise coupled around each wiring point to electrically connect the
speaker array 4 to the audio receiver 3.
[0020]
In another embodiment, as shown in FIG. 1B, the speaker array 4 receives audio such that the
array 4 and the audio receiver 3 are not physically connected but maintain a radio frequency
connection using a wireless protocol It can be connected to machine 3. For example, the speaker
array 4 may include a WiFi receiver for receiving audio signals from the corresponding WiFi
transmitter of the audio receiver 3. In some embodiments, the speaker array 4 can include an
integrated amplifier that drives the transducers 5 using wireless audio signals received from the
audio receiver 3. As described above, the speaker array 4 can be a stand-alone unit including
signal processing according to the technology described below and components for driving each
of the transducers 5.
[0021]
Although shown in FIG. 1A as including two loudspeaker arrays 4, the audio system 1 can
include any number of loudspeaker arrays 4 connected to the audio receiver 3 by wireless or
wired connection . For example, audio system 1 includes six speaker arrays representing front
left channel, front center channel, front right channel, rear right surround channel, rear left
surround channel and low frequency channel (eg, subwoofer) It can contain four. In another
embodiment, as shown in FIG. 1B, audio system 1 may include a single speaker array 4. This
single speaker array 4 may be a sound bar style speaker array.
[0022]
FIG. 3 shows a functional block diagram and some constituent hardware components of the
audio receiver 3 according to one embodiment. The components shown in FIG. 3 represent
elements included in the audio receiver 3 and should not be interpreted as excluding other
components. Each element of FIG. 3 will be described below as an example.
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[0023]
Audio receiver 3 may include a plurality of inputs 8 for receiving one or more channels of audio
program content using electrical, wireless or optical signals from one or more external sound
sources 2. The inputs 8 can be digital inputs 8A and 8B, and a set of analog inputs 8C and 8D
(including a set of physical connectors located on the exposed surface of the audio receiver 3).
For example, the input 8 can include high resolution multimedia interface (HDMI (registered
trademark)) input, optical digital input (TOSLINK), coaxial digital input and phono input. In one
embodiment, the audio receiver 3 receives an audio signal through a wireless connection with an
external sound source 2. In the present embodiment, the input 8 may be a wireless adapter for
communication with the external sound source 2 using a wireless protocol. For example, the
wireless adapter may be BLUETOOTH.RTM., IEEE.RTM. 802.11x, cellular wide area mobile
communication system (GSM.RTM.), Cellular code division multiple access (CDMA) or long term
evolution (LTE). It can be used to communicate.
[0024]
As shown in FIGS. 1A and 1B and as described above, the external sound source 2 transmits one
or more channels of audio program content to the audio receiver 3 by means of a laptop
computer or a wireless or wired connection. It can be any device that can. In one embodiment,
the external source 2 and the audio receiver 3 are integrated into one non-divisible unit. In this
embodiment, the loudspeaker array 4 can also be integrated into the same unit. For example, the
external sound source 2 and the audio receiver 3 can be mounted on one computer with
transducers 5 integrated on the left and right sides of the unit.
[0025]
Returning to the audio receiver 3, the general signal flow from the input 8 will now be described.
When first looking at the digital inputs 8A and 8B and receiving digital audio signals through the
inputs 8A and / or 8B, the audio receiver 3 uses the decoder 9A or 9B to voice the electrical,
optical or radio signals, Decode into a set of audio channels representing program content. For
example, the decoder 9A can receive a single signal comprising six audio channels (e.g., a 5.1
signal) and decode the signal into six audio channels. The decoder 9 uses any codec or technique
(including Advanced Acoustic Coding (AAC), MPEG Audio Layer 2, MPEG Audio Layer 3 and Free
Lossless Audio Codec (FLAC)) The encoded audio signal can be decoded.
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[0026]
Referring to analog inputs 8C and 8D, each analog signal received by analog inputs 8C and 8D
can represent a single audio channel of audio program content. Thus, multiple analog inputs 8C
and 8D may need to receive each channel of a piece of audio program content. The audio channel
may be digitized by each analog to digital converter 10A and 10B to form a digital audio channel.
[0027]
The digital audio channels from each of the decoders 9A and 9B and the analog to digital
converters 10A and 10B are output to the multiplexer 12. The multiplexer 12 selectively outputs
one set of audio channels based on the control signal 13. The control signal 13 can be received
from the control circuit or processor of the audio receiver 3 or from an external device. For
example, the control circuit that controls the operation mode of the audio receiver 3 can output
the control signal 13 to the multiplexer 12 that selectively outputs one set of digital audio
channels.
[0028]
Multiplexer 12 provides the selected digital audio channel to array processor 14. The channels
output by multiplexer 12 are processed by array processor 14 to produce a set of processed
audio channels. This process can operate in both time and frequency domains using transforms
such as fast Fourier transform (FFT). Array processor 14 may be a dedicated processor such as
application specific integrated circuits (ASICs), a general purpose microprocessor, a field
programmable gate array (FPGA), a digital signal controller, or a set of hardware logic structures
(eg, filters, arithmetic logic units) And dedicated state machines). The array processor 14
generates a set of signals for driving the transducers 5 of the speaker array 4 based on the input
from the position estimator 15 and / or the crosstalk matrix generator 16.
[0029]
The position estimator 15 determines the position of the listener who is one or more people in
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the room 7. For example, the position estimator 15 may determine the physical coordinates of
the listener 6 in the room 7 or the position of the listener 6 with respect to the loudspeaker array
4 (e.g. distance and angle with respect to the loudspeaker array 4 or coordinates). FIG. 4A shows
the listener 6 at the position of coordinates x A and y A with respect to the speaker array 4 in the
room 7. As the listener 6 moves through the room 7 and while sound is being emitted by the
speaker array 4, the position estimator 15 determines the position of the listener 6. Although
described with respect to a single listener 6, the position estimator 15 can determine the
positions of multiple listeners 6 in the room 7. Although the position estimator 15 described
herein adaptively determines the position of the listener 6 in the room 7, in one embodiment, the
position estimator determines the position of the listener 6 after the initial position
determination. Consider it to be fixed.
[0030]
The position estimator 15 can use any device or algorithm that determines the position of the
listener 6. In one embodiment, the user input device 17 is connected to a position estimator 15
which assists the position determination of the listener 6. The user input device 17 allows the
listener 6 to periodically input the position of the listener 6 relative to the speaker array 4 or
another known object in the room 7. For example, while watching a movie, the listener 6 may
first sit on the couch with coordinates x A, y A relative to the speaker array 4 as shown in FIG.
4A. The listener 6 can input this position to the position estimator 15 using the user input device
17. In the middle of the movie, the listener 6 may decide to move to a table located at x B, y B
relative to the loudspeaker array 4 as shown in FIG. 4B. Based on this movement, the listener 6
can input this new position into the position estimator 15 using the user input device 17. The
user input device 17 may be a wired or wireless keyboard, a mobile device, or any other similar
device that allows the listener 6 to input a position to the position estimator 15. In one
embodiment, the entered values are non-numeric or relative. For example, the listener 6 can
indicate that it is located to the right of the speaker array 4.
[0031]
In another embodiment, a microphone 18 can be connected to the position estimator 15 to assist
in determining the position of the listener 6. In the present embodiment, the microphone 18 is
located together with the listener 6 or in proximity to the listener 6. The audio receiver 3 drives
the speaker array 4 to emit a set of test audio which is detected by the microphone 18 and
provided to the position estimator 15 for processing. The position estimator 15 determines the
propagation delay of the test voice during propagation from the speaker array 4 to the
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microphone 18 based on the detected sound. This propagation delay can then be used to
determine the position of the listener 6 relative to the loudspeaker array 4.
[0032]
The microphone 18 can be connected to the position estimator 15 using a wired or wireless
connection. In one embodiment, the microphone 18 is integrated into a mobile device (e.g., a
mobile phone) and the detected sound is a position estimator 15 using one or more wireless
protocols (e.g., BLUETOOTH and IEEE 802.11x). Sent to The microphone 18 can be any type of
acoustic / electrical transducer or sensor (such as a microelectromechanical system (MEMS)
microphone, a piezoelectric microphone, an electret condenser microphone, or a dynamic
microphone). The microphone 18 can provide a range of polar patterns such as cardioid,
omnidirectional, and figure of eight. In one embodiment, the polarity pattern of the microphone
18 can fluctuate continuously with time. Although shown and described as a single microphone
18, in one embodiment, multiple microphones or microphone arrays can be used to detect the
sound in the room 7.
[0033]
In another embodiment, the camera 19 can be connected to the position estimator 15 to assist in
determining the position of the listener 6. The camera 19 may be a video camera or a still image
camera facing the room 7 in the same direction as the speaker array 4. The camera 19 records
video of an area in front of the speaker array 4 or a set of still images. Based on these records,
the camera 19 tracks the face or other part of the body of the listener 6 alone or in conjunction
with the position estimator 15. The position estimator 15 can determine the position of the
listener 6 based on the tracking of the face / body. In one embodiment, the camera 19
periodically tracks the form of the listener 6 so that the position of the listener 6 can be updated
and remain accurate while the speaker array 4 outputs audio program content. For example,
while the song is being played through the speaker array 4, the camera 19 can continuously
track the listener 6.
[0034]
The camera 19 can be connected to the position estimator 15 using a wired or wireless
connection. In one embodiment, the camera 19 is integrated into a mobile device (e.g. a mobile
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phone) and the recorded video or still images are located using one or more wireless protocols
(e.g. BLUETOOTH and IEEE 802.11x) It is sent to the estimator 16. Although shown and
described as a single camera 18, in one embodiment, multiple cameras can be used for face /
body tracking.
[0035]
In yet another embodiment, one or more infrared (IR) sensors 20 are connected to the position
estimator 15. The IR sensor 20 captures IR light emitted from an object in the area in front of the
speaker array 4. Based on these detected IR measurements, the position estimator 15 can
determine the position of the listener 6. In one embodiment, the IR sensor 20 operates
periodically so that the position of the listener 6 can be updated and remain accurate while the
speaker array 4 outputs sound. For example, while a song is being played through the speaker
array 4, the IR sensor 20 can continuously track the listener 6.
[0036]
The infrared sensor 20 can be connected to the position estimator 15 using a wired or wireless
connection. In one embodiment, the IR sensor 20 is integrated into a mobile device (e.g. a mobile
phone) and the detected infrared radiation is position estimated using one or more wireless
protocols (e.g. BLUETOOTH and IEEE 802.11x) Is sent to the transmitter 15.
[0037]
Although described above with respect to a single listener 6, in one embodiment, the position
estimator 15 can determine the positions of multiple listeners 6 relative to the speaker array 4.
In the present embodiment, each position of the listener 6 is used to adjust the sound emitted by
the speaker array 4.
[0038]
Using any combination of the above mentioned techniques, the position estimator 15 calculates
the position of the listener 6 and supplies it to the crosstalk matrix generator 16 for processing.
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The crosstalk matrix generator 16 reads the beam pattern matrix based on the detected position
of the listener 6. The read beam pattern matrix achieves one or more predefined constraints for
emitting sound through the loudspeaker array 4. In one embodiment, the constraints include: (1)
Maximizing / increasing the left channel of one piece of audio program content and minimizing /
decreasing the right channel in the left ear of listener 6; (2) listener With the right ear of 6,
maximizing / enhancing the right channel, and minimizing / reducing the left channel, and (3) in
all other areas of room 7 Minimizing / reducing speech. The method of generating the beam
pattern matrix is described in more detail below.
[0039]
In one embodiment, while minimizing the second channel in one ear, reducing or eliminating the
second channel in that ear as maximizing / increasing the first channel During that time, mention
may be made of increasing the perceived sound of the first channel with its ear. This recognition
can be defined by the power of the first channel being substantially greater than the power of the
second channel.
[0040]
Assuming that the right audio input channel is d R and the left audio input channel is d L, the
beam pattern matrix is the right and left ears of the listener with the right output channel f R and
the left output channel f L Generate each. This can be expressed by the following equation. Here,
G is a beam pattern matrix.
[0041]
In this equation, the right output channel f R and the left output channel f L generated by the
listener's right and left ears, respectively, substantially correspond to the right audio input
channel d R and the left audio input channel d L Each is the same or identical.
[0042]
In one embodiment, the audio receiver 3 stores a plurality of beam pattern matrices
corresponding to different positions of the one or more listeners 6 with respect to the speaker
array 4 in the room 7.
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For example, the audio receiver 3 can store different beam pattern matrices for each coordinate
pair x, y (representing the position of the listener 6 in the room 7 relative to the speaker array 4).
As described above, the beam pattern matrix can be associated with the positions of the plurality
of listeners 6 in the room 7.
[0043]
In one embodiment, the beam pattern matrix can be stored on the local medium of the audio
receiver 3. For example, the beam pattern matrix can be stored in a microelectronic, volatile or
non-volatile medium integrated in the audio receiver 3. In another embodiment, the beam pattern
matrix is located at a remote server or system and can be accessed by the audio receiver 3 using
a wired or wireless network connection. For example, the audio receiver 3 uses one or more of
IEEE 802.11x, IEEE 802.3, cellular wide area mobile communication system (GSM), cellular code
division multiple access (CDMA) and long term evolution (LTE) The beam pattern matrix can be
accessed.
[0044]
As mentioned above, while minimizing sound in all other areas of room 7, the beam pattern
matrix maximizes the sound intended for the right and left ears of listener 6, based on the
position of listener 6 Can be In one embodiment, each beam pattern matrix consists of a set of
complex values that describe the filter (e.g., amplitude and phase). Each of these filters is for a
particular frequency that drives the corresponding transducer 5 of the speaker array 4 to
generate the left and right audio channels. For example, the beam pattern matrix can be
expressed as:
[0045]
In the above beam pattern matrix example, each r corresponds to a complex filter value that
describes the amplitude and phase applied to each of the t transducers 5 of the speaker array 4
for the left and right audio channels for a particular frequency. . As mentioned above, the
crosstalk canceller 16 reads the beam pattern matrix for one or more desired frequencies
corresponding to the detected position of the listener 6. The read beam pattern matrix is
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provided to the array processor 14 to process one or more audio channels representing a piece
of audio program content. Although the equations used herein are described in the frequency
domain, the filter values of the beam pattern matrix can be implemented in either the time or
frequency domain.
[0046]
The complex filter values describe the amplitude and phase of the sound emitted by each
transducer 5 to achieve one or more predefined constraints (used to calculate the initial beam
pattern matrix). As mentioned above, among the constraints, the following may be included: (1)
Maximizing / increasing the left channel of one audio program content with the left ear of the
listener 6 and minimizing / decreasing the right channel, (2) the listener Maximizing / enhancing
the right channel and minimizing / decreasing the left channel with the right ear, and (3)
minimizing speech in all other areas of room 7 Making / reducing. Due to these constraints, the
audio receiver 3 emits sound towards the listener 6. By radiating the sound towards the listener
6, rather than the other areas of the room 7, crosstalk cancellation is achieved with minimal
influence of fluctuations on the frequency response of the room 7.
[0047]
Having read out the one or more beam pattern matrices for the set of frequencies corresponding
to the current position of the listener 6, the crosstalk canceller 16 supplies the beam pattern
matrix to the array processor 14. Array processor 14 processes each audio channel of a piece of
audio program content received from multiplexer 12 in accordance with the beam pattern
matrix. For example, the array processor 14 may use each complex filter value of the beam
pattern matrix as weight and phase values for the corresponding audio signal provided to the
transducer 5 of the speaker array. The array processor 14 causes the transducer 5 to emit sound
based on the filter values of the beam pattern matrix so that each of the constraints is achieved.
(E.g. (1) maximizing the left channel of a piece of audio program content with the left ear of the
listener 6, and minimizing the right channel, (2) with the right ear of the listener 6, There are
maximizing the right channel and minimizing the left channel, and (3) minimizing speech in all
other areas of the room 7. )
[0048]
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15
By maximizing the sound directed to the listener 6, the room 7 has little effect on the listener 6,
as the sound is minimized in most areas of the room 7. Furthermore, because there are more
control orders that can be used for adjustment (ie, multiple transducers 5 of the speaker array 4),
crosstalk due to adverse conditions (eg, sensitivity variations of transducers 5 and the effects of
room 7) Cancellation may be less affected.
[0049]
Array processor 14 may operate in both time and frequency domains using a transform such as a
fast Fourier transform (FFT). Array processor 14 may be a dedicated processor such as an
application specific integrated circuit (ASIC), a general purpose microprocessor, a field
programmable gate array (FPGA), a digital signal controller, or a set of hardware logic structures
(eg, filters, arithmetic logic units) , And dedicated state machines etc.). As shown in FIG. 3,
processed segments of audio program content are communicated from the array processor 14 to
one or more digital to analog converters 21 to generate one or more different analog signals. The
analog signals generated by the digital to analog converter 21 are provided to a power amplifier
22 to drive selected transducers 5 of the loudspeaker array 4.
[0050]
The audio receiver 3 can adjust the output of the speaker array 4 constantly based on the
movement of the listener 6 detected by the position estimator 15. For example, upon detecting
that the listener 6 has moved, the crosstalk canceller supplies the updated set of beam pattern
matrices to the array processor 14 for processing.
[0051]
Referring now to FIGS. 5A and 5B, a system for generating beam pattern matrices will be
described. The beam pattern matrix can be generated by the audio receiver 3 during the initial
configuration of the audio system 1 or by a remote unit of the manufacturing or research facility.
In the following description, the generation of the beam pattern matrix will be described with
respect to the audio receiver 3. However, in alternate embodiments, different instruments can be
used to calculate these matrices and provide them to one or more audio receivers.
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16
[0052]
The crosstalk canceller 16 generates one or more beam pattern matrices for one set of
frequencies based on the position of the listener 6 in the room 7. In one embodiment, the audio
receiver 3 includes one or more microphones 22 that assist in the generation of the beam
pattern matrix. The microphone 22 can include the microphone 18 used to determine the
listener 6 position, or the microphone 22 can be independent of the microphone 18. The
microphone 22 is initially used to adjust the audio receiver 3 and the loudspeaker array 4 of the
room 6. Once the beam pattern matrix has been generated, the microphone 22 can be removed /
stored.
[0053]
As shown in FIG. 5A, the microphone 22A is placed to represent the right ear of the listener 6,
the microphone 22B is placed to represent the left ear of the listener 6, and the microphone 22C
is separated from the microphones 22A and 22B in the room 7 Placed in other areas of In
another embodiment shown in FIG. 5B, the microphone can be placed to represent multiple
listeners 6. For example, the microphones 22A 1 and 22B 1 are placed to represent the right and
left ears of the first listener 6. Microphones 22A 2 and 22B 2 are placed to represent the right
and left ears of the second listener. Then, the microphone 22C is placed in another area of the
room 7 apart from the microphones 22A 1, 22B 1, 22A 2 and 22B 2. Although described below
with respect to a single listener 6, the crosstalk matrix generator 16 may operate in the same
manner in the case of multiple listeners 6.
[0054]
The microphone 22 can be connected to the crosstalk canceller 16 using a wired or wireless
connection. In one embodiment, the microphone 22 is integrated into a mobile device (e.g. a
mobile phone) and the detected sound is cross-talk canceled 16 using one or more wireless
protocols (e.g. BLUETOOTH and IEEE 802.11x) Sent to The microphone 22 can be any type of
acoustic / electrical transducer or sensor, including a micro-electro-mechanical system (MEMS)
microphone, a piezoelectric microphone, an electret condenser microphone or a dynamic
microphone. The microphone 22 can provide a range of polar patterns such as cardioid,
omnidirectional, and figure of eight. In one embodiment, the polarity pattern of the microphone
22 can fluctuate continuously with time.
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[0055]
In one embodiment, the audio receiver 3 generates a series of test sounds used to drive the
transducers 5 of the speaker array 4. The test speech can be varied in duration, frequency and
power, and can be divided into right and left channels corresponding to the left and right ears of
the listener 6. Using the microphone layout shown in FIG. 5A, the crosstalk matrix generator 16
calculates a beam pattern matrix for each frequency at a set of frequencies. The generated beam
pattern matrix drives each transducer 5 of the speaker array 4 based on one or more constraints.
In one embodiment, the constraints include: (1) Maximize / increase the left channel of one audio
program content with the microphone 22A, and minimize / decrease the right channel, (2) the
right with the microphone 22B No channel or no left channel, and (3) no sound at microphone
22C or very low level speech To generate. For example, for the right channel test speech z L and
the left channel test speech z R, the above mentioned constraints are identical to the right
channel test speech z R and the left channel test tone z L for the microphones 22A and 22B,
respectively. While the microphone 22C hardly detects any sound. Using the constraints
described above, the crosstalk generator 16 generates the right channel and the left channel at
the left and right ears of the listener 6, respectively, without allowing the audio to flow to the left
and right ears from the opposite channel. It is possible to calculate a beam pattern matrix that
accurately generates
[0056]
FIG. 6 illustrates a method 23 of generating a beam pattern matrix using the microphone
configurations shown in FIGS. 5A and 5B, according to one embodiment. Method 23 begins with
operation 24 of determining the position of listener 6 in room 7. The listener 6 in this operation
may not be the actual listener 6 but instead be the position of the microphones 22A and 22B
representing the listener 6's ear. In one embodiment, the position estimator 15 may determine
the position of the listener 6 using one or more of the user input device 17, the microphone 18,
the camera 19, and the IR sensor 20. The position of the listener 6 can be expressed as
coordinates with respect to the loudspeaker array 4 or any other known anchorage of the room
7.
[0057]
Simultaneously with the positioning of the listener 6, a plurality of test sounds are emitted by the
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18
audio receiver 3 into the room 7 in an operation 25. The test speech is divided into a right
channel z R and a left channel z L corresponding to the right and left ears of the listener 6,
respectively. The test speech can vary in duration, frequency and power for each channel z R and
z L.
[0058]
At act 26, test audio penetrates the room 7, the microphone 22 detects test audio, and the
detected audio is transmitted to the crosstalk canceller. As described above and shown in FIG. 5A,
the microphone 22A is placed to represent the right ear of the listener 6, the microphone 22B is
placed to represent the left ear of the listener 6, and the microphone 22C is remote from the
microphones 22A and 22B, Located in other areas of room 7. The detected voice can be
transmitted to the crosstalk canceller using a wired or wireless connection.
[0059]
In act 27, the speech detected from each microphone 22 is provided to the crosstalk matrix
generator 16 to generate a beam pattern matrix corresponding to the location of the listener 6.
Crosstalk matrix generator 16 calculates beam pattern matrices that aim to achieve a set of
predefined constraints. The beam pattern matrix is a set of complex filters that describe the
amplitude / weight and phase applied to the audio signal (applied to each transducer 5 of the
speaker array 4) to achieve one or more constraints. Contains the value. In one embodiment, the
constraints include: (1) Maximize the left channel of one audio program content with the
microphone 22A and minimize the right channel, (2) Maximize the right channel with the
microphone 22B, minimize the left channel And (3) not producing sound at the microphone 22C,
or producing very low level sound. To achieve these constraints, the problem can be formulated
as a least squares problem. In this case, a large weight is applied to a portion (for example,
crosstalk cancellation) related to maximizing and minimizing the right and left channels of the
microphones 22A and 22B, respectively, in the beam pattern matrix. On the other hand,
relatively smaller weights are applied to portions of the beam pattern matrix associated with
minimizing speech at the microphone 22C. The overall effect is that method 23 achieves
crosstalk cancellation while minimizing speech away from listener 6.
[0060]
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In one embodiment, the transfer function of the room 7 corresponding to the position of the
listener 6 is determined. The determined transfer function is used to compensate for the effects /
disturbances caused by the test speech propagating in the room 7 during beam pattern matrix
generation.
[0061]
At act 28, the calculated beam pattern matrix is stored and / or one or more audio receivers 3 to
perform crosstalk cancellation, as described above, in various rooms and environments. Can be
sent to The transmission can be performed by wired or wireless connection. In one embodiment,
the calculated beam pattern matrix is stored in another audio receiver 3 during production at the
manufacturing facility.
[0062]
The method 23 can be performed constantly for multiple possible positions of the listener 6 so
that a corresponding beam pattern matrix can be generated for a set of frequencies. Each beam
pattern matrix for each corresponding position may be sent to one or more audio receivers 3 to
perform crosstalk cancellation using one or more constraints, as described above. Using the
constraints described above, the cross talk generator 16 does not allow sound from the opposite
channel to flow to the left and right ears of the listener 6, respectively, with the right and left
channels in the left and right ears of the listener 6, respectively. It is possible to calculate a beam
pattern matrix that accurately generates the left channel.
[0063]
As described above, embodiments of the present invention may be articles of manufacture loaded
with the following machine-readable media (eg, a memory based on microelectronics). The
machine readable medium stores instructions for programming one or more data processing
components (generally referred to herein as a "processor") to perform the operations described
above. In other embodiments, some of these operations may be performed by specific hardware
components, including wired logic (eg, dedicated digital filter blocks and state machines). Those
operations may instead be performed by any combination of programmed data processing
components and fixed wiring circuit components.
11-04-2019
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[0064]
While certain embodiments have been described and illustrated in the accompanying drawings,
such embodiments are merely illustrative of the broad invention and are not limiting. It should
also be understood that the present invention is not limited to the specific arrangements and
arrangements shown and described, as various other modifications will occur to those skilled in
the art. Accordingly, the description is considered to be illustrative rather than limiting.
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