3d sound reproducing method and apparatus.

(54) Title: METHOD AND APPARATUS FOR PLAYING THREE-DIMENSIONAL SOUND (3D). (54) Tltle: 3D SOUND REPRODUCING METHOD AND APPARATUS.

(57) Summary

The present invention relates to a method and apparatus for reproducing three-dimensional (3D) sound. The method includes transmitting sound signals through a head-related transfer filter (HRTF) corresponding to a first elevation, generating a plurality of sound signals by replicating the filtered sound signals, amplifying or attenuating each of the sound signals. replicated sound based on a gain value corresponding to each speaker, through which the replicated sound signals will be produced, and produce the amplified and attenuated sound signals through the corresponding speakers.

(57) Abstract

Provided are a three-dimensional (3D) sound reproducing method and apparatus. The method ineludes transmitting sound signáis through a head related transfer filter (HRTF) corresponding to a first elevation, generating a plurality of sound signáis by replicating the filtered sound signáis, amplifying or attenuating each of the replicated sound signáis based on a gain value corresponding to each of speakers, through which the replicated sound signáis will be output, and outputting the amplified or attenuated sound signáis through the corresponding speakers.

METHOD AND APPARATUS FOR PLAYING THREE-DIMENSIONAL SOUND (3D)

Field of the Invention

The methods and apparatus consistent with the exemplary modalities relate to the reproduction of three-dimensional (3D) sound, and more particularly, the location of a virtual sound source at a predetermined elevation.

Background of the Invention

With developments in video and sound processing technologies, content with high image and sound quality is being provided. Users who demand content that has high image and sound quality now require realistic images and sounds, and therefore 3D sound and image research is being actively conducted.

3D sound is generated by providing a plurality of speakers in different positions on a level surface and producing sound signals that are equal to or different from each other according to the speakers so that a user can experience a spatial effect.

However, sound can currently be generated from various elevations, as well as various points on the level surface. Therefore, a technology is necessary to effectively reproduce sound signals Ref. 238249 that are generated at different levels from each other.

Brief Description of the Invention

Solution to the problem

The present invention provides a method of reproducing 3D sound and apparatus thereof for locating a virtual sound source at a predetermined elevation. Advantageous Effects of the Invention

In accordance with the present embodiment, it is possible to provide a three-dimensional 3D effect. And, in accordance with the present embodiment, it is possible that the virtual sound source can be effectively located at a predetermined elevation.

Brief Description of the Figures

The foregoing and other features and advantages of the present invention will become more apparent by describing in detail the exemplary embodiments thereof with reference to the accompanying figures in which:

FIG. 1 is a block diagram of a 3D sound reproducing apparatus according to an exemplary embodiment;

FIG. 2a is a block diagram of the 3D sound reproducing apparatus for locating a virtual sound source at a predetermined elevation using 5-channel signals;

FIG. 2b is a block diagram of a 3D sound reproducing apparatus for locating a virtual sound source at a predetermined elevation using a sound signal in accordance with another exemplary embodiment;

FIG. 3 is a block diagram of a 3D sound reproducing apparatus for locating a virtual sound source at a predetermined elevation using a 5-channel signal in accordance with another exemplary embodiment;

FIG. 4 is a diagram showing an example of a 3D sound reproducing apparatus for locating a virtual sound source at a predetermined elevation producing 7-channel signals through 7 speakers in accordance with an exemplary embodiment;

FIG. 5 is a diagram showing an example of a 3D sound reproducing apparatus for locating a virtual sound source at a predetermined elevation producing 5-channel signals through 7 speakers in accordance with an exemplary embodiment;

FIG. 6 is a diagram showing an example of a 3D sound reproducing apparatus for locating a virtual sound source at a predetermined elevation producing 7-channel signals through 5 speakers in accordance with an exemplary embodiment;

FIG. 7 is a diagram of a speaker system for locating a virtual sound source at a predetermined elevation in accordance with an exemplary embodiment; and

FIG. 8 is a flow chart illustrating a 3D sound reproduction method according to an exemplary embodiment.

Detailed description of the invention

Exemplary embodiments provide a method and apparatus for reproducing 3D sound, and in particular, a method and apparatus for locating a virtual sound source at a predetermined elevation.

In accordance with one aspect of an exemplary embodiment, a 3D sound reproduction method is provided, the method includes: transmitting a sound signal through a predetermined filter that generates 3D sound corresponding to a first elevation; replicate the filtered sound signal to generate a plurality of sound signals; performing at least one of amplification, attenuation, and delay on each of the replicated sound signals based on at least one of a gain value and a delay value corresponding to each of a plurality of speakers, through the which replicated sound signals will be produced; and produce the sound signals

<td>that have</td><td>suffered at least</td><td>one</td><td>of</td><td>the processes</td><td>of</td>

<td colspan="2">amplification, attenuation, and</td><td colspan="2">delay</td><td>through</td><td>the</td>

<td>speakers</td><td>corresponding.</td><td></td><td></td><td></td><td></td>

<td></td><td colspan="2">The default filter</td><td>can</td><td>include filter</td><td>of</td>

head related transfer (HRTF).

Transmission of the sound signals through the HRTF may include transmitting at least one of a top left channel signal representing a sound signal generated from a left side of a second elevation and a top right channel signal representing a signal. of sound generated from a right side of the second lift through the HRTF.

The method may further include generating the upper left channel signal and the upper right channel signal by mixing the sound signal, when the sound signal does not include the upper left channel signal and the upper right channel signal.

The transmission of the sound signal through the

HRTF may include transmitting at least one of a front left channel signal representing a sound signal generated from a left side and a front right channel signal representing a sound signal generated from a front right side through the HRTF, when the sound signal does not include a top left channel signal representing a sound signal generated from a left side of a second elevation and a top right channel signal representing a sound signal generated from a right side of the second elevation .

The HRTF can be generated by dividing a first HRTF that includes information about a path from the first lift to a user's ears by a second HRTF that includes information about a path from a speaker location, through which the signal Sound will be produced, to the user's ears.

Sound signal production may include: generating a first sound signal by mixing the sound signal obtained by amplifying the filtered upper left channel signal according to a first gain value with the sound signal obtained by amplifying the upper right channel signal filtered according to a second gain value; generating a second sound signal by mixing the sound signal obtained by amplifying the upper left channel signal according to the second gain value with the sound signal obtained by amplifying the filtered upper right channel signal according to the first gain value; and producing the first sound signal through a speaker placed on a left side and producing the second sound signal through a speaker placed on a right side.

The production of the sound signals may include: generating a third sound signal by mixing a sound signal which is obtained by amplifying a left rear signal representing a sound signal generated from a left rear side according to a third gain value with the first sound signal; generating a fourth sound signal by mixing a sound signal obtained by amplifying a rear right signal representing a sound signal generated from a rear right side according to the third gain value with the second sound signal; and produce the third sound signal through a left rear speaker and the fourth sound signal through a right rear speaker.

The production of the sound signals may additionally include muting at least one of the first sound signal and the second sound signal according to a location at the first elevation, where the virtual sound source will be located.

The transmission of the sound signal through the

HRTF may include: obtaining information about the location where the virtual sound source will be located; and determine the HRTF, through which the sound signal is transmitted, based on the location information.

Performing at least one of the amplification, attenuation, and delay processes may include determining at least one of the gain values ​​and the delay values ​​that will be applied to each of the replicated sound signals based on at least one of a current speaker location, a listener location, and a virtual sound source location.

Determination of at least one of the gain value and delay value may include determining at least one of the gain value and delay value with respect to each of the replicated sound signals as a given value, when the information about of the listener's location is not obtained.

Determination of at least one of the gain value and delay value may include determining at least one of the gain value and delay value with respect to each of the replicated sound signals as an equal value, when the information about of the listener's location is not obtained.

In accordance with an aspect of another exemplary embodiment, a 3D sound reproducing apparatus is provided including: a filter unit that transmits a sound signal through an HRTF corresponding to a first elevation; a replication unit that generates a plurality of sound signals by replicating the filtered sound signal; an amplification / delay unit that performs at least one of the amplification, attenuation, and delay processes with respect to each of the replicated sound signals based on a gain value and a delay value corresponding to each of a plurality of loudspeakers, through which the replicated sound signals will be produced; and an output unit that produces the sound signals that have undergone at least one of the amplification, attenuation, and delay processes through the corresponding speakers.

The default filter is Head Related Transfer Filter 5 (HRTF).

The filter unit can transmit at least one of a top left channel signal representing a sound signal generated from a left side of a second elevation and a top right channel signal representing a sound signal generated from a right side of the second elevation through the HRTF.

The 3D sound reproducing apparatus may further comprise: a mixing unit which generates a top left channel signal and a top right channel signal, when the sound signal does not include the top left channel signal and the top channel signal right.

The filter unit can transmit at least one of a front left channel signal representing a sound signal generated from a front left side and a front right channel signal representing a sound signal generated from a front right side through the HRTF, when the sound signal does not include a top left channel signal representing the sound signal generated from a left side of a second elevation and a top right channel signal representing the sound signal generated from a right side of the second elevation .

The HRTF is generated by dividing a first HRTF that includes information about a path from the first lift to a user's ears by a second HRTF that includes information about a path from a speaker location, through which the signal from Sound will be produced, to the user's ears.

The output unit comprises: a first mixing unit which generates a first sound signal by mixing a sound signal which is obtained by amplifying the filtered upper left channel signal according to a first gain value with a sound signal which is obtained by amplifying the filtered upper right channel signal according to a second gain value;

a second mixing unit which generates a second sound signal by mixing a sound signal obtained by amplifying the filtered upper left channel signal according to the second gain value with a sound signal obtained by amplifying the channel signal upper right filtered according to the first gain value; and a rendering unit which produces the first sound signal through a speaker placed on a left side and produces the second sound signal through a speaker placed on a right side.

The output unit comprises:

a third mixing unit which generates a third sound signal by mixing a sound signal that is or obtained by amplifying a rear left signal representing a sound signal generated from a rear left side according to a third gain value with the first sound signal; and a fourth mixing unit which generates a fourth sound signal by mixing a sound signal obtained by amplifying a rear right signal that represents a sound signal generated from a rear right side according to the third gain value with the second sound signal;

where the rendering unit produces the third sound signal through a left rear speaker and the. fourth sound signal through a rear right speaker.

The rendering unit comprises a controller which mutes at least one of the first and second sound signals according to a location at the first elevation, where the virtual sound source will be located.

Mode of the Invention

This application claims the benefit of

United States Provisional Application No. 61 / 362,014, filed on July 7, 2010 at the United States Patent and Trademark Office, Korean Patent Application No. 10-2010-0137232, filed on December 28, 2010, and Korean Patent Application No. 10-2011-0034415, filed on April 13, 2011, at the Korean Intellectual Property Office, the descriptions of which are incorporated herein by reference in their entirety.

Then the exemplary modalities will be described in detail with reference to the accompanying figures. In this description, the term unit means a hardware component and / or a software component that is executed by a hardware component such as a processor.

FIG. 1 is a block diagram of a 3D sound reproducing apparatus 100 according to an exemplary embodiment.

The 3D sound reproducing apparatus 100 includes a first unit 110, a replication unit 120, an amplifier. 130, and an output unit 140.

Filter unit 110 transmits a sound signal through a predetermined filter that generates 3D sound corresponding to a predetermined elevation. Filter unit 110 can transmit a sound signal through a head-related transfer filter (HRTF) corresponding to a predetermined elevation. The

HRTF includes information about a path from a spatial position of a sound source to both ears of a user, that is, a frequency transmission characteristic. HRTF causes a user to recognize 3D sound by a phenomenon whereby complex pitch characteristics such as diffraction on the skin of the human head and pinna reflection, as well as simple pitch differences such as a difference in inter-aural level (ILD) and an inter-aural time difference (ITD) are changed according to the sound arrival directions.

Since there is only one HRTF in each direction in a space, 3D sound can be generated due to the above characteristics.

Filter unit 110 uses the HRTF filter to model a sound that is generated from one position at a higher elevation than that of current speakers that are arranged on a level surface. Equation 1 below is an example of HRTF used in filter unit 110.

HRTF = HRTF₂/ HRTF! ----------------------- (1)

HRTF₂ it is HRTF representing the pitch information from a position of a virtual sound source to a user's ears, and HRTF! It is HRTF that represents the passing information from a current speaker position to the user's ears. Since a sound signal is produced from the current speaker, for the user to recognize that the sound signal is produced from a virtual speaker, the HRTF₂ corresponding to a predetermined elevation is divided by HRTFi corresponding to the level surface (or elevation of the current speaker).

An optimal HRTF corresponding to a predetermined elevation varies from person to person, such as a footprint. However, it is impossible to calculate the HRTF for each user and apply the calculated HRTF for each user. Accordingly, HRTF is calculated for some users in a user group, who have similar properties (for example, physical properties such as age and height, or trends such as favorite frequency band and favorite music), and then a Representative value (for example, an average value) can be determined as the HRTF applied to all users included in the corresponding user group.

Equation 2 below is a result of filtering the sound signal using the HRTF defined in Equation 1 above.

AND₂ (f) = Y_x(f) * HRTF ----------------------- (2)

<td>Yi (f)</td><td>is</td><td>a value</td><td>turned to</td><td>a</td><td>Band of</td>

<td>frequency from</td><td>the</td><td>output of</td><td>sound signal</td><td>than</td><td>an user</td>

<td>listen from</td><td>the</td><td colspan="2">current speaker, and Y₂(F)</td><td>is</td><td>a value</td>

converted to a frequency band from the sound signal output that a user listens to from the virtual speaker.

Filter unit 110 can only filter some channel signals from a plurality of channel signals included in the sound signal.

The sound signal may include sound signals corresponding to a plurality of channels. Next, a 7-channel signal is defined for the convenience of the description. However, the 7-channel signal is an example, and the sound signal may include a channel signal representing the sound signal generated from directions different from the seven directions that will now be described.

A center channel signal is a sound signal generated from a front center portion, and is produced through a center speaker.

A front right channel signal is a sound signal generated from a right side of a front portion, and is produced through a front right speaker.

2.0 A front left channel signal is a sound signal generated from a left side of the front portion, and is output from a front left speaker.

A rear right channel signal is a sound signal generated from a right side of a rear portion, and is output through a rear right speaker.

A rear left channel signal is a sound signal generated from a left side of the rear portion, and is produced through a rear left speaker.

A top right channel signal is a sound signal generated from a top right portion, and is output through a top right speaker.

A top left channel signal is a sound signal generated from a top left portion, and is output through a top left speaker.

When the sound signal includes the upper right channel signal and the upper left channel signal, the filter unit 110 filters the upper right channel signal and the upper left channel signal. The upper right signal and upper left signal that are then filtered are used to model a virtual sound source that is generated from a desired elevation.

When the sound signal does not include the upper right signal and the upper left signal, the filter unit. 110 filters the front right channel signal and the front left channel signal. The front right channel signal and the front left channel signal are then used to model the virtual sound source generated from a desired elevation.

In some exemplary embodiments, the sound signal that does not include the upper right channel signal and the upper left channel signal (eg 2.1 channel or 5.1 channel signal) are mixed to generate the upper right channel signal and the upper left channel. Then the mixed upper right channel signal and upper left channel signal can be filtered.

Replication unit 120 replicates the filtered channel signal into a plurality of signals. Replication unit 120 replicates the filtered channel signal as many times as the number of speakers through which the filtered channel signals will be produced. For example, when the filtered sound signal is produced as the upper right channel signal, the upper left channel signal, the rear right channel signal, and the rear left channel signal, the replication unit 120 makes four replicates of the filtered channel signal. The number of replicas made by replication unit 120 can vary depending on the exemplary modalities; however, it is desirable that two or more replicas be generated so that the filtered channel signal can be produced at least as the rear right channel signal and the rear left channel signal.

The speakers through which the upper right channel signal and the upper left channel signal will be played are placed on the level surface. As an example, the speakers can be attached directly above the front speaker that reproduces the front right channel signal.

Amplifier 130 amplifies (or attenuates) the filtered sound signal according to a predetermined gain value. The gain value may vary depending on the type of the filtered sound signal.

For example, the upper right channel signal produced through the upper right speaker is amplified according to a first gain value, and the upper right channel signal produced through the upper left speaker is amplified according to a second value of gain. Here, the first gain value can be greater than the second gain value. Also, the upper left channel signal produced through the upper right speaker is amplified according to the second gain value, and the upper left channel signal produced through the upper left speaker is amplified according to the first gain value of so the channel signals corresponding to the left and right speakers can be output.

In related art, an ITD method has been used primarily to generate a virtual sound source at a desired position. The ITD method is a method of locating the virtual sound source at a desired position by producing the same sound signal from a plurality of speakers with time differences. The ITD method is suitable for locating the virtual sound source in the same plane in which the current speakers are located. However, the ITD method is not an appropriate way to locate the virtual sound source at a position that is located higher than a current speaker elevation.

In exemplary modes, the same sound signal is produced from a plurality of speakers with different gain values. In this way, according to an exemplary embodiment, the virtual sound source can be easily located at an elevation that is higher than that of the current speaker, or at a certain elevation without considering the elevation of the current speaker.

The 14 0 output unit produces one or more amplified channel signals through the corresponding speakers. Output unit 140 may include a mixer (not shown) and a rendering unit (not shown).

The mixer mixes one or more channel signals.

The mixer mixes the upper left channel signal that is amplified according to the first gain value with the upper right channel signal that is amplified according to the second gain value to generate a first sound component, and mixes the upper left channel signal that is amplified according to the second gain value and the upper right channel signal that is amplified according to the first gain value to generate a second sound component.

Also, the mixer mixes the rear left channel signal that is amplified according to a third gain value with the first sound component to generate a third sound component, and mixes the rear right channel signal that is amplified according to the third gain value with the second sound component to generate a fourth sound component.

The rendering unit renders the mixed or unmixed sound components and sends them to the corresponding speakers.

The rendering unit sends the first sound component to the upper left speaker, and sends the second sound component to the upper right speaker.

If there is no upper left speaker or upper right speaker, the rendering unit can send the first sound component to the front left speaker and can send the second sound component to the front right speaker.

Also, the rendering unit sends the third sound component to the rear left speaker, and sends the fourth sound component to the rear right speaker.

The operations of the replication unit 120, amplifier 130, and output unit 140 can vary depending on the number of channel signals included in the sound signal and the number of speakers. The examples of operations of the 3D sound reproducing apparatus according to the number of channel signals and speakers will be described later with reference to FIGS. 4 to 6.

FIG. 2a is a block diagram of a 3D sound reproducing apparatus 100 for locating a virtual sound source at a predetermined elevation using 5-channel signals in accordance with an exemplary embodiment.

A mixer 210 mixes 5-channel signals 201 to generate 7-channel signals that include a top left channel signal 202 and a top right channel signal 203.

Upper left channel signal 202 is input to a first HRTF 111, and upper right channel signal 203 is input to a second HRTF 112.

The first HRTF 111 includes information about a passage from a left virtual sound source to the user's ears, and the second HRTF 112 includes information about a passage from a right virtual sound source to the user's ears. The first HRTF 111 and the second HRTF 112 are filters for modeling virtual sound sources at a predetermined elevation that is greater than that of current speakers.

The upper left channel signal and the upper right channel signal passing through the first HRTF 111 and the second HRTF 112 are input to replication units 121 and 122.

Each of the replication units 121 and 122 make two replicates of each of the upper left channel signal and the upper right channel signal that are transmitted through HRTFs 111 and 112. The upper left channel signal and signal Replicated upper right channel strips are transferred to the first to third amplifiers 131, 132, and 133.

The first amplifier 131 and the second amplifier 132 amplify the replicated upper left signal and upper right signal according to the speaker that produces the signal and the type of the channel signals. Furthermore, the third amplifier 133 amplifies at least one channel signal included in the 5-channel signals 201.

In some exemplary embodiments, the 3D sound reproducing apparatus 100 may include a first delay unit (not shown) and a second delay unit (not shown) in place of the first and second amplifiers 131 and 132, or may include all of the first and second amplifiers 131 and 132, and the first and second delay units. This is because the same result as that of the variation of the gain value can be obtained when the delay values ​​of the filtered sound signals vary depending on the speakers.

Output unit 140 mixes the amplified upper left channel signal, upper right channel signal, and 5 channel signal 201 to produce the mixed signals as 7 channel 205 signals. 7 channel 205 signals are sent to each one of the speakers.

In another exemplary embodiment, when 7-channel signals are input, mixer 210 can be omitted.

In another exemplary embodiment, the 3D sound reproducing apparatus 100 may include a filter determining unit (not shown) and an amplification / delay coefficient determining unit (not shown).

The filter determination unit selects a

Appropriate HRTF according to a position where the virtual sound source will be located (i.e. an elevation angle and a horizontal angle). The filter determining unit can select an HRTF corresponding to the virtual sound source using mapping information between the location of the virtual sound source and the HRTF. The location information of the virtual sound source can be received through other modules such as applications (software or hardware), or can be entered from the user. For example, in a game application, a location where the virtual sound source is located may vary depending on time, and the filter determination unit may change the HRTF according to the variation of the virtual sound source location.

The amplification / delay coefficient determining unit can determine at least one of an amplification coefficient (attenuation) and a delay coefficient of the replicated sound signal based on at least one of a current speaker location, a location of the virtual sound source, and a listener location. If the amplification / delay coefficient determination unit - does not recognize the listener location information in advance, the amplification / delay coefficient determination unit may select at least one of an amplification coefficient and a predetermined delay coefficient.

FIG. 2b is a block diagram of a 3D sound reproducing apparatus 100 for locating a virtual sound source at a predetermined elevation using a sound signal in accordance with another exemplary embodiment.

In FIG. 2b, a first channel signal that is included in a sound signal will be described for the convenience of the description. However, the present exemplary embodiment can be applied to other channel signals included in the sound signal.

The 3D sound reproducing apparatus 100 may include a first HRTF 211, a replication unit 221, and an amplification / delay unit 231.

A first HRTF 211 is selected based on the location information of the virtual sound source, and the first channel signal is transmitted through the first HRTF

211. The location information of the virtual sound source can include elevation angle information and horizontal angle information.

Replication unit 221 replicates the first channel signal after it is filtered into one or more sound signals. In FIG. 2b, it is assumed that replication unit 221 replicates the first channel signal as many times as the number of current speakers.

The amplification / delay unit 231 determines the amplification / delay coefficients of the first replicated channel signals respectively corresponding to the speakers, based on at least one of the current speaker location information, location information of a listener, and location information of the virtual sound source. Amplification / delay unit 231 amplifies / attenuates the first replicated channel signals based on the determined amplification (or attenuation) coefficients, or delays the first replicated channel signal based on the delay coefficient. In an exemplary embodiment, the amplification / delay unit 231 can simultaneously perform amplification (or attenuation) and delay of the first replicated channel signals based on the amplification (or attenuation) coefficients and the determined delay coefficients.

Amplification / delay unit 231 generally determines the amplification / delay coefficient of the first replicated channel signal for each of the speakers; however, the amplification / delay unit 231 can determine that the amplification / delay coefficients of the speakers are equal to each other when the location information of the listener is not obtained, and therefore the first channel signals that are equal to Yes, they can be sent respectively through the speakers. In particular, when the amplification / delay unit 231 does not obtain the location information from the listener, the amplification / delay unit 231 can determine the amplification / delay coefficient for each of the speakers as a predetermined value (or an arbitrary value). ).

FIG. 3 is a block diagram of a 3D sound reproducing apparatus 100 for locating a virtual sound source at a predetermined elevation using 5-channel signals in accordance with another exemplary embodiment. A signal distribution unit 310 extracts a front right channel signal 302 and a front left channel signal 3 03 from the 5 channel signal, and transfers the extracted signals to the first HRTF 111 and the second HRTF 112.

The 3D sound reproducing apparatus 100 of the present exemplary embodiment is the same as that described with reference to FIG. 2 except that the sound components applied to the filter units 111 and 112, the replication units 121 and 121, and the amplifiers 131, 132, and 133 are the front right channel signal 3 02 and the front left channel signal 303. Therefore, detailed descriptions of the 3D sound reproducer apparatus 100 of the present exemplary embodiment will not be provided here.

FIG. 4 is a diagram showing an example of a 3D sound reproducing apparatus 100 for locating a virtual sound source at a predetermined elevation producing 7-channel signals through 7 speakers in accordance with another exemplary embodiment.

FIG. 4 will be described based on the input sound signals, and then described based on the sound signals produced through the speakers.

Sound signals including a front left channel signal, an upper left channel signal, a rear left channel signal, a center channel signal, a rear right channel signal, an upper right channel signal, and a signal front right channel are inserted into the 3D sound player

100 .

The front left channel signal is mixed with the center channel signal that is attenuated by a factor B, and then transferred to a front left speaker.

The upper left channel signal passes through an HRTF corresponding to an elevation that is 30 (greater than that of the upper left speaker, and is replicated into four channel signals).

Two upper left channel signals are amplified by a factor A, and then mixed with the upper right channel signal. In some exemplary embodiments, after mixing the upper left channel signal that is amplified by factor A with the upper right channel signal, the mixed signal can be replicated into two signals. One of the mixed signals is amplified by a factor D, and then mixed with the rear left channel signal and output through the rear left speaker. The other of the mixed signals is amplified by a factor E, and then produced through the upper left speaker.

Two remaining upper left channel signals are mixed with the upper right channel signal that is amplified by factor A. One of the mixed signals is amplified by factor D, and then mixed with the rear right channel signal and produces through the rear right speaker. The other of the mixed signals is amplified by the E factor, and is produced through the upper right speaker.

The rear left channel signal mixes with the upper right channel signal that is amplified by factor D and the upper left channel signal that is amplified by factor D (A, and is output through the rear left speaker.

The center channel signal is replicated into three signals. One of the replicated center channel signals is attenuated by factor B, and then mixed with the front left channel signal and produced through the front left speaker. Another replicated center channel signal is attenuated by factor B, and after this, it mixes with the front right channel signal and is output through the front right speaker. The other of the replicated center channel signals is attenuated by a factor C, and then produced through the center speaker.

The rear right channel signal is mixed with the upper left channel signal that is amplified by factor D and the upper right channel signal that is amplified by factor D (A, and then output through the rear right speaker .

The upper right signal passes through an HRTF corresponding to an elevation that is 30 (greater than that of the upper right speaker, and then replicates into four signals).

Two upper right channel signals are mixed with the upper left channel signal that is amplified by factor A. One of the mixed signals is amplified by factor D, and mixed with the rear left channel signal and produced through of the rear left speaker. The other of the mixed signals is amplified by the E factor, and is produced through the upper left speaker.

Two replicated right upper channel signals are amplified by factor A, and mixed with the left upper channel signals. One of the mixed signals is amplified by the D factor, and mixed with the rear right channel signal and output through the rear right speaker. The other of the mixed signals is amplified by the E factor, and is produced through the upper right speaker.

The front right channel signal is mixed with the center channel signal that is attenuated by factor B, and is output through the front right speaker.

Then the sound signals that are finally produced through the speakers after the processes described above are as follows:

(front left channel signal + center channel signal (B) is output through the front left speaker;

(rear left channel signal + D ((upper left channel signal (A + upper right channel signal)) is output through the rear left speaker;

(E (upper left channel signal (A + upper right channel signal)) is output through the upper left speaker;

(C (center channel signal) is produced through the center speaker;

(E ((upper right channel signal (A + upper left channel signal)) is output through the upper right speaker;

(rear right channel signal + D ((upper right channel signal (A + upper left channel signal)) is output through the rear right speaker; and (front right channel signal + center channel signal (B) is produces through the front right speaker.

In FIG. 4, the gain values ​​to amplify or attenuate the channel signals are only examples, and various gain values ​​can be used which can cause the left speaker and the right speaker to produce corresponding channel signals. Also, in some exemplary modes, gain values ​​can be used to output the channel signals that do not correspond to the speakers through the left and right speakers.

FIG. 5 is a diagram showing an example of a 3D sound reproducing apparatus 100 for locating a virtual sound source at a predetermined elevation producing 5-channel signals through 7 speakers in accordance with another exemplary embodiment.

The 3D sound reproducing apparatus shown in FIG. 5 is the same as that shown in FIG. 4 except that the sound components input to an HRTF are a front left channel signal and a front right channel signal. Therefore, the sound signals produced through the speakers are as follows:

(front left channel signal + center channel signal (B) is output through the front left speaker;

(rear left channel signal + D ((front left channel signal (A + front right channel signal)) is output through the rear left speaker;

(E ((front left channel signal (A + front right channel signal)) is output through the upper left speaker;

(C (center channel signal) is produced through the center speaker;

(E ((front right channel signal (A + front left channel signal)) is output through the upper right speaker;

(rear right channel signal + D ((front right channel signal (A + front left channel signal)) is output through the rear right speaker; and (front right channel signal + center channel signal (B) is produces through the front right speaker.

FIG. 6 is a diagram showing an example of a 3D sound reproducing apparatus 100 for locating a virtual sound source at a predetermined elevation producing 7-channel signals through 5 speakers, in accordance with another exemplary embodiment.

The 3D sound reproducing apparatus 100 of FIG.

it is the same as that shown in FIG. 4 except that the output signals are supposed to be output through the upper left speaker (the speaker for the upper left channel signal 413) and the upper right speaker (the speaker for the upper right channel signal 415) on the FIG. 4, are produced through the front left speaker (the speaker for the front left channel signal 611) and the front right speaker (the speaker for the front right channel signal 615) respectively. Therefore, the sound signals produced through the speakers are as follows:

(front left channel signal + (center channel signal (B) + E ((front left channel signal (A + front right signal)) is output from the front left speaker:

(rear left channel signal + D ((front left channel signal (A + front right channel signal)) is output through the rear left speaker;

(C (center channel signal) is produced through the center speaker;

(E (front right channel signal (A + front left channel signal)) is output through the upper right speaker;

(rear right channel signal + D ((front right channel signal (A + front left channel signal)) is output through the rear right speaker; and (front right channel signal + (center channel signal (B) + E ((front right channel signal (A + front left channel signal)) is output through the front right speaker.

FIG. 7 is a diagram of a speaker system for locating a virtual sound source at a predetermined elevation in accordance with an exemplary embodiment.

The speaker system of FIG. 7 includes a center speaker 710, a front left speaker 721, a front right speaker 722, a rear left speaker 731, and a rear right speaker 732.

As described above with reference to FIGS. 4 up to 6, to locate a virtual sound source at a predetermined elevation, a top left channel signal and a top right channel signal that have passed through a filter are amplified or attenuated by gain values ​​that are different according to the speakers are then inserted into the front left speaker 721, the front right speaker 722, the rear left speaker 731, and the rear right speaker 732.

Although not shown in FIG. 7, a top left speaker (not shown) and a top right speaker (not shown) can be placed above the left speaker. front 721 and front right speaker 722. In this case, the upper left channel signal and the upper right channel signal passing through the filter are amplified by the gain values ​​that are different according to the speakers and input to the upper left speaker (not shown), the upper right speaker (not shown), the left rear speaker 731, and the right rear speaker 732.

A user recognizes that the virtual sound source is located at a predetermined elevation when the upper left channel signal and the upper right channel signal that are filtered out are output from one or more speakers in the speaker system. Here, when the filtered upper left channel signal or upper right channel signal is muted on one or more speakers, you can adjust a location of the virtual sound source in a left and right direction.

When the virtual sound source will be located in a center portion at a predetermined elevation, the front left speaker 721, the front right speaker 722, the rear left speaker 731, and the rear right speaker 732 produce the upper left and upper channel signals filtered right, or only the rear left speaker 731 and rear right speaker 732 can produce the filtered upper left and upper right channel signals. In some exemplary embodiments, at least one of the filtered upper left and upper right channel signals can be output through the center speaker 710. However, the center speaker 710 does not contribute to adjusting the location of the virtual sound source in left and right direction.

0 When it is desired that the virtual sound source be located to the right side at a predetermined elevation, the front right speaker 722, the rear left speaker 731, and the rear right speaker 732 can produce the upper left and upper right channel signals.

When the virtual sound source is desired to be located to the left side at a predetermined elevation, the front left speaker 721, the rear left speaker 731, and the rear right speaker 732 can produce the filtered upper left and upper right channel signals .

Even though it is desired that the virtual sound source be located on the left or right side at the predetermined elevation, the filtered upper left and upper right channel signals produced through the rear left speaker 731 and the rear right speaker 732 cannot be silence.

In some exemplary modes, the location of the virtual sound source in the left and right direction can be adjusted by adjusting the gain value to amplify or attenuate the upper left and upper right channel signals, without muting the upper left and Filtered rights produced through one or more speakers.

FIG. 8 is a flow chart illustrating a 3D sound reproduction method according to an exemplary embodiment.

In step S810, a sound signal is transmitted through an HRTF corresponding to a predetermined elevation.

In step S820, the filtered sound signal is replicated to generate one or more replicated sound signals.

In step S830, each of the one or more replicated sound signals is amplified according to a gain value corresponding to a speaker, through which the sound signal will be produced.

In operation S840, the one or more amplified sound signals are respectively produced through the corresponding speakers.

In related art, a top speaker is installed at a desired elevation to produce a sound signal that is generated at the elevation; however, it is not easy to install the top speaker on the ceiling. Therefore, the top speaker is generally placed above the front speaker, which can cause a desired elevation not to be reproduced.

When the virtual sound source is located at a desired location using an HRTF, the location of the virtual sound source can be effectively done in the left and right direction on a horizontal plane. However, localization using the HRTF is not suitable for locating the virtual sound source at an elevation that is higher or lower than that of current speakers.

In contrast, according to exemplary embodiments, one or more channel signals that pass through the HRTF are amplified by gain values ​​that are different from each other according to the speakers, and are output through the speakers. In this way, the virtual sound source can be effectively located at a predetermined elevation using the speakers positioned in the horizontal plane.

The exemplary modalities can be written as computer programs and can be implemented in general-purpose digital computers that run the programs which are stored on a computer-readable recording medium.

Examples of the computer-readable recording medium include magnetic storage media (eg, ROMs, floppy disks, hard drives, etc.), and optical recording media (eg, CD-ROMs, or DVDs).

While exemplary modalities are particularly shown and described, it will be understood by those of ordinary art experience that various changes in form and detail can be made herein without departing from the spirit and scope of the inventive concept as defined by the following claims.

It is noted that in relation to this date, the best method known by the applicant to put the aforementioned invention into practice is the one that is clear from the present description of the invention.