KR100636167B1 - Wireless audio system using virtual sound algorithm - Google Patents

Abstract

A wireless audio system using a virtual acoustic algorithm is disclosed. An audio system according to the present invention generates an audio signal of a plurality of channels in which a sound field is expanded according to a predetermined virtual sound algorithm from an input audio signal and transmits the generated multiple channel audio signal according to a WLAN protocol. And an audio receiver configured to wirelessly receive the audio signals of the plurality of channels transmitted from the transmitter and the audio transmitter, and to distribute and reproduce the received audio signals of the plurality of channels to the corresponding speaker for each channel. According to the present invention, a wider sound field and a multi-channel stereo sound can be realized through one wireless unit equipped with two speakers and a virtual sound algorithm optimized for a deployment environment.

Description

Wireless audio system using virtual sound algorithm {Wireless audio system using virtual sound algorithm}

1 is a block diagram of an audio system according to an embodiment of the present invention.

FIG. 2A is a diagram illustrating a first virtual sound processor in the audio system of FIG. 1.

FIG. 2B is a configuration diagram of an audio system in which the first virtual sound processor of FIG. 2A is used.

FIG. 2C is a listening space of an audio system in which the first virtual sound processor of FIG. 2A is used.

FIG. 3A is a diagram for describing a second virtual sound processor in the audio system of FIG. 1.

FIG. 3B is a configuration diagram of an audio system in which the second virtual sound processor of FIG. 3A is used.

FIG. 3C is a listening space of an audio system in which the second virtual sound processor of FIG. 3A is used.

FIG. 4A illustrates a third virtual sound processor in the audio system of FIG. 1.

4B is a first listening space of an audio system in which the third virtual sound processor of FIG. 4A is used.

4C is a second listening space of the audio system in which the third virtual sound processor of FIG. 4A is used.

The present invention relates to an audio system for wirelessly transmitting and receiving an audio signal, and more particularly, to a wireless audio system using a virtual sound algorithm is disclosed.

In general, a wireless audio system configures two wireless speakers as separate units and uses them as rear left speakers and rear right speakers. At this time, each wireless speaker requires a radio frequency (RF) receiving module.

In order to reduce the number of RF receiving modules, mounting two speakers in one RF receiving unit narrows the sound field of the sound reproduced in the speakers. This is because the maximum angle at which the speaker emits an audio signal is physically limited.

Therefore, the conventional wireless audio system is inexpensive because a separate RF receiving module must be provided for each wireless speaker, and when the speakers are mounted in one RF receiving unit, the sound field of the sound reproduced by the speakers is narrowed, and the rear speaker is used. There is a problem that the implemented wireless speaker cannot be used as a front speaker.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an audio system in which a plurality of speakers mounted in one unit and sharing an RF reception module form an extended sound field by using a virtual sound algorithm in a wireless audio system.

An audio system according to an embodiment of the present invention for achieving the above technical problem, generates a multi-channel audio signal of the sound field is expanded according to a predetermined virtual sound algorithm from the input audio signal and the generated multi-channel audio An audio transmitter for transmitting a signal according to a WLAN protocol and a plurality of channels of audio signals transmitted by the audio transmitter are wirelessly received, and the audio signals of the plurality of channels are distributed to and reproduced by a speaker for each channel. It includes an audio receiver.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a block diagram of an audio system according to an embodiment of the present invention. Referring to FIG. 1, an audio system includes an audio transmitter 100 and an audio receiver 150.

The audio transmitter 100 includes the A / D converter 110, the multiplexer 115, the virtual sound processor 120, the algorithm selector 125, the WLAN modulator 130, the RF modulator 135, and the first. The amplifier 140 and the transmitting antenna 145 is included.

An A / D converter 110 converts the analog multi-channel audio signals input to the L _in terminal and the R _in terminal into digital multi-channel audio signals.

The multiplexer unit 115 receives a digital multichannel audio signal through an I2S (Inter-IC Sound) bus. I2S is a serial bus design for digital audio devices and technologies, including CD players, digital signal processors (DSPs), and digital television sound. In I2S designs, audio data is processed separately from the clock signal. Thus, the I2S bus consists of three serial bus lines: one line for time division multiplexed data channels, one word select line and one clock line.

The multiplexer unit 115 also receives a digital multi-channel audio signal converted by the A / D converter unit 100-1.

The multiplexer unit 115 selects any one multi-channel audio signal from the digital multi-channel audio signal input through the I2S bus and the digital multi-channel audio signal input from the A / D converter unit 100-1, and then the virtual sound processor. Send to 120.

The virtual sound processor 120 generates an audio signal of a plurality of channels in which a sound field is extended according to a predetermined virtual sound algorithm from an input audio signal. For example, the virtual sound processor 120 generates an audio signal of two channels of which the sound field is extended according to a predetermined virtual sound algorithm from the 5.1-channel audio signal that is input. The reason why the two-channel audio signal is generated is because the number of speakers 180 and 185 mounted in the audio receiver 150 is two.

The predetermined virtual sound algorithm is basically an algorithm for extending the sound field of the sound reproduced by the speakers 180 and 185 of the audio receiver 150. The sound field is a virtual space created by the arrangement of sound images, and is a space where sound waves of an audible frequency exist. Sound image is a place where the focus of sound reproduced from the speaker is formed and is a sound source of sense perceived by human beings. A sound source is an object or location that actually generates sound.

The virtual sound algorithm used by the virtual sound processor 120 may be generated by using a head related transfer function (HRTF). The head transfer function will be described below.

Stereophonic sound is a sound in which spatial information is added to a sound so that a listener who is not located in a space where a sound source is generated can perceive a sense of direction, distance, and spatial feeling when the sound is heard. Such stereophonic sound is classified into a surround type multichannel method and a binaural type 2 channel method according to a reproduction method.

There are two methods of generating a binaural two-channel stereophonic sound by recording and filtering. In the filtering method, the head transfer function is used as the filter. The filtering method is a method of concatenating a head transfer function and a simple sound to position a sound image at a desired spatial location.

The head transfer function emits an impulse signal, such as white noise, from a speaker placed at various angles in the form of a sphere around a dummy head in an anechoic chamber, and measures the impulse response measured by microphones mounted on both ears of the dummy head. (Fourier) Converted.

The path of sound waves from the sound source to the two ears of a person passes directly through the air or arrives at the ears by reflection, scattering, diffraction, and the like, and then through reflection, diffraction, resonance, etc. by the head and ear wheels. The sound waves through this path are changed and the desired information is extracted by the auditory system. The head transfer function is a transfer function measured in advance by thinking of this path as a function (system). This head transfer function is defined for a single sound source.

The spatiality of the sound source can be perceived because two signal differences incident on the two ears occur due to the unique characteristics of the head delivery system of each individual. Information about the characteristics of the two signal differences is contained in the head transfer function, and by using this, it is possible to generate a binaural type stereoscopic sound with spatial information added to a simple non-stereoscopic sound.

Since the head transfer function depends on the angle of incidence, it is necessary to measure the head transfer function for the impulse at various positions and construct it as a DB. Then, the head transfer function corresponding to the desired position is selected from the DB to perform simple sound and convolution operation to locate the sound image at the corresponding position.

The MIT Media Lab published the head transfer function database, measured at 710 points, using the Knowles Electronic Manikin for Auditory Research (KEMAR) dummy head over the Internet. The Electronics and Telecommunications Research Institute (ETRI) built a database of head transfer functions using Neumann dummy heads.

The head transfer function measured in a specific room is called a room transfer function (RTF), and using this, a sound field characteristic of the room can be generated.

The virtual sound processor 120 includes a plurality of virtual sound algorithms. The virtual sound algorithms included in the virtual sound processor 120 are basically algorithms for extending a sound field of a sound reproduced by the speakers 180 and 185 of the audio receiver 150. The virtual sound algorithms included in the virtual sound processor 120 are algorithms optimized according to the use and arrangement of the audio receiver 150, respectively. Each specific use and arrangement will be described later.

The algorithm selector 125 selects an algorithm to be used in the virtual sound processor 120 among the virtual sound algorithms included in the virtual sound processor 120. That is, the listener selects a desired virtual sound algorithm in the algorithm selector 125 according to the use and arrangement of the audio receiver 150, and the virtual sound processor 120 converts an input audio signal according to the selected virtual sound algorithm. .

The algorithm selector 125 may be implemented by a switch. In addition, the algorithm selecting unit 125 may select one algorithm, or may select two or more algorithms. When two or more algorithms are selected, each algorithm is applied to the audio signal input to the virtual sound processor 120 in parallel. Detailed description thereof will be described later.

 It is also possible for the virtual sound processor 120 to use the virtual sound algorithm provided in another module without having the virtual sound algorithms by itself.

The WLAN modulator 130 generates a baseband signal of a plurality of channels by modulating a plurality of channels of audio signals generated by the virtual sound processor 120 according to a wireless local area network (WLAN) protocol. A wireless LAN refers to a local area network (LAN) using radio waves or an infrared transmission method. Examples of wireless LAN protocols include IEEE 802.11 and Bluetooth.

The RF modulator 135 mounts the baseband signals of the plurality of channels generated by the WLAN modulator 130 on a carrier and modulates them into radio frequency (RF) signals of the plurality of channels. The first amplifier 140 amplifies the RF signals of the plurality of channels modulated by the RF modulator 135. The transmitting antenna 145 wirelessly transmits RF signals of a plurality of channels amplified by the first amplifier 140.

The audio receiver 150 includes a reception antenna 160, an RF demodulator 165, a WLAN demodulator 170, a second amplifier 175, a first speaker 180, and a second speaker 185. .

The receiving antenna 160 receives a plurality of channels of RF signals transmitted wirelessly from the transmitting antenna 145. The RF demodulator 165 demodulates the RF signals of the plurality of channels received by the reception antenna 160 to extract the baseband signals of the plurality of channels. The WLAN demodulator 170 demodulates the multi-channel baseband signal extracted by the RF demodulator 150-2 according to the WLAN protocol used by the WLAN modulator 130. The second amplifier 175 amplifies the audio signals of the plurality of channels demodulated by the WLAN demodulator 150-3. The first speaker 180 and the second speaker 185 reproduce the audio signal of the channel among the audio signals of the plurality of channels amplified by the second amplifier 175.

The audio receiver 150 may be implemented as one unit. The audio receiver 150 has only one receiving antenna 160 and is equipped with two speakers 180 and 185. That is, the first speaker 180 and the second speaker 185 share the reception antenna 160.

The sound reproduced and listened to by the first speaker 180 and the second speaker 185 is affected by the virtual sound algorithm used in the virtual sound processor 120. As a result, the sound field reproduced by the first speaker 180 and the second speaker 185 is basically expanded. Accordingly, the problem that the sound field is narrowed by mounting the two speakers 180 and 185 to one wireless unit 150 is solved.

In addition, sounds reproduced and listened to by the first speaker 180 and the second speaker 185 are differentiated according to the algorithm selected by the algorithm selector 130.

FIG. 2A is a diagram illustrating the first virtual sound processor 120 in the audio system of FIG. 1. Referring to FIG. 2A, the first virtual sound processor 120 may include an audio signal of a front left (FL) channel, an audio signal of a front right (FR) channel, and an audio of a center channel. Signal, an audio signal 204 of the Rear Left (RL) channel and an audio signal 205 of the Rear Right (RR) channel. That is, the input audio signal of the first virtual sound processor 120-1 is an audio signal of 5.1 channels.

The first virtual sound processor 120-1 applies the first virtual sound algorithm to the audio signals of the RL channel and the RR channel among the 5.1-channel audio signals, and the two-channel audio signals 214 and 215 of which the sound field is extended. Create

The audio signal 201 of the FL channel, the audio signal 202 of the FR channel, and the audio signal 203 of the center channel are bypassed without applying the first virtual acoustic algorithm.

FIG. 2B is a diagram illustrating an audio system in which the first virtual sound processor 120-1 of FIG. 2A is used. Referring to FIG. 2B, the audio system includes an FL speaker 221, an FR speaker 222, a center speaker 223, and a subwoofer 230 in addition to the audio transmitter 100 and the audio receiver 150.

The audio signal 211 of the FL channel, the audio signal 212 of the FR channel, and the audio signal 213 of the center channel bypassed by the first virtual sound processor 120-1 are respectively wired FL speakers 221 and wired. The sound is reproduced through the FR speaker 222 and the wired center speaker 213, and the sound is also reproduced through the subwoofer 230.

The audio receiver 150 receives two channels of audio signals wirelessly transmitted from the audio transmitter 100. The received two-channel audio signal is distributed and reproduced to the first speaker 180 and the second speaker 185 of the audio receiver 150 for each channel.

FIG. 2C illustrates a listening space of an audio system in which the first virtual sound processor 120-1 of FIG. 2A is used. Referring to FIG. 2C, the audio receiver 150 is disposed behind the first listening position 250.

In the listening space of FIG. 2C, the two speakers 180 and 185 of the audio receiver 150 are mounted in one wireless unit 150, but the sound heard in the 250 in the first listening position is like This is the same as the sound when the speakers 180 and 185 are spaced apart by a predetermined interval. That is, the two speakers 180 and 185 of the wireless speaker device 150 perform the functions of the RL speaker and the RR speaker, which are disposed apart by a predetermined interval, respectively.

This is because the first virtual sound algorithm basically expands the sound field of the sound reproduced in the speakers 180 and 185 of the wireless speaker device 150.

The first virtual sound algorithm is used when the purpose of the audio receiver 150 is a rear speaker. Speakers of the RL channel arranged at regular intervals by processing the audio signal 204 of the RL channel and the audio signal 205 of the RR channel according to the first virtual acoustic algorithm and playing through the audio receiver 150 disposed rearward. And the speaker of the RR channel. Accordingly, the listener uses the sound reproduced by the FL speaker 221, the FR speaker 222, and the center speaker 223, and the sound reproduced by the audio receiver 150 to simulate a 5.1-channel virtual channel at the first listening position 250. Appreciate stereoscopic sound.

FIG. 3A is a diagram for describing a second virtual sound processor 120-2 in the audio system of FIG. 1. Referring to FIG. 3A, the second virtual sound processor 120-2 may include an audio signal 201 of an FL channel, an audio signal 202 of an FR channel, an audio signal 203 of a center channel, and an audio signal of an RL channel. 204 and an audio signal 205 of the RR channel. That is, the second virtual sound processor 120-2 receives an audio signal of 5.1 channels.

The second virtual sound processor 120-2 generates a two-channel audio signal having an extended sound field by applying the second virtual sound algorithm to the input 5.1-channel audio signal. The first virtual sound processor 120-1 receives an audio signal of 5.1 channels and receives an audio signal of the FL channel, an FR signal, and a center channel, as well as two audio signals 214 and 215 of which the sound field is expanded. The audio signal is also output, but the second virtual sound processor 120-2 receives the same 5.1-channel audio signal and outputs only the two-channel audio signals 311 and 312 in which the sound field is extended.

FIG. 3B is a diagram illustrating an audio system in which the second virtual sound processor 120-2 of FIG. 3A is used. Referring to FIG. 3B, the audio receiver 150 receives two channels of audio signals wirelessly transmitted from the audio transmitter 100. The received two-channel audio signal is distributed and reproduced to the first speaker 180 and the second speaker 185 of the audio receiver 150 for each channel.

The two-channel audio signal processed and output by the second virtual sound processor 120-2 is distributed and reproduced to the first speaker 180 and the second speaker 185 of the audio receiver 150 for each channel.

FIG. 3C illustrates a listening space of an audio system in which the second virtual sound processor 120-2 of FIG. 3A is used. Referring to FIG. 3C, the audio receiver 150 is disposed in front of the second listening position 260.

In the listening space of FIG. 3C, two speakers 180 and 185 of the audio receiver 150 are mounted in one wireless unit, and a separate speaker other than the speakers 180 and 185 of the audio receiver 150 is provided. It is provided.

However, the sound to be heard at the second listening position 260 is similar to the sound when the speakers for each channel with respect to the 5.1 channel audio signal input to the second virtual sound processor 120-2 are arranged at a predetermined interval apart. same. That is, the two speakers 180 and 185 of the audio receiver 150 perform the functions of the FL speaker, the FR speaker, the center speaker, the RL speaker, and the RR speaker, respectively, spaced apart by a predetermined interval.

This is because the second virtual sound algorithm basically expands the sound field of the sound reproduced by the two speakers 180 and 185 of the audio receiver 150. In addition, the second virtual sound algorithm, when the audio signal of the two channels generated by the second virtual sound processor 120-2 is reproduced through the speakers 180 and 185 of the audio receiver 150, the second virtual sound processor. This is because the 5.1-channel audio signal inputted to (120-2) produces an effect similar to that of reproduction.

The second virtual sound processor 120-2 is used to replace the speakers for reproducing the 5.1-channel audio signals 201 to 205 with one audio receiver 150. The audio signals 201 through 205 of the 5.1 channel are processed according to the second virtual sound algorithm and reproduced through the audio receiver 150 disposed at the front side to be used as the 5.1 channel speakers arranged at regular intervals. Accordingly, the listener views the 5.1-channel virtual stereo sound at the second listening position 260 using the sound reproduced by the audio receiver 150.

4A is a diagram illustrating a third virtual sound processor 120-3 in the audio system of FIG. 1. Referring to FIG. 4A, the third virtual sound processor 120-3 may include the audio signal 201 of the FL channel, the audio signal 202 of the FR channel, the audio signal 203 of the center channel, and the audio signal of the RL channel. 204 and an audio signal 205 of the RR channel.

The third virtual sound processor 120-3 applies the third virtual sound algorithm and the second virtual sound algorithm in parallel to the input 5.1 channel audio signal.

That is, the 5.1-channel audio signals 201 to 205 input to the third virtual sound processor 120-3 are generated as two-channel audio signals 411 and 412 having an extended sound field according to the third virtual sound algorithm. In parallel with this, the sound field is generated as two-channel audio signals 413 and 414 according to the second virtual sound algorithm. Accordingly, the output audio signal of the third virtual sound processor 120-4 becomes an audio signal 411 to 414 having a total of four channels.

The two-channel audio signals 411 and 412 generated according to the third virtual sound algorithm are reproduced through wired speakers for each channel.

Since the constant of the virtual acoustic algorithm is different according to the location and structure of the wired speaker and the wireless speaker, a third virtual sound algorithm different from the second virtual sound algorithm for the wireless speaker is used for the wired speaker. The sound field extended by the virtual acoustic algorithm depends on the constant of the virtual acoustic algorithm.

The second virtual sound algorithm used in parallel with the third virtual sound algorithm is the same as the second virtual sound algorithm described with reference to FIGS. 3A to 3C.

4B is a first listening space of an audio system in which the third virtual sound processor 120-3 of FIG. 4A is used. Referring to FIG. 4B, the FL speakers 221, the FR speakers 222, and the center speaker 223, which are wired speakers, are disposed in front of the first listening position 250. This listening space is the same as the audio receiver 150 is removed from the listening space of FIG. 2C.

The two-channel audio signals 411 and 412 generated by the third virtual sound algorithm in the third virtual sound processor 120-3 are reproduced by the wired FL speaker 221 and the wired FR speaker 222.

At this time, the sound listened to at the first listening position 250 is similar to the sound when the speakers for each channel with respect to the 5.1 channel audio signal input to the third virtual sound processor 120-3 are arranged at a predetermined interval apart. same. That is, the two wired speakers 221 and 222 respectively perform the functions of the FL speaker, the FR speaker, the center speaker, the RL speaker, and the RR speaker arranged at a predetermined interval apart.

This is because the third virtual sound algorithm basically expands the sound field of the sound reproduced by the two wired speakers 221 and 222. In addition, the third virtual sound algorithm, when the audio signal 411, 412 of the two channels generated by the third virtual sound processor 120-2 is reproduced through the two wired speakers (221, 222) This is because the 5.1-channel audio signals 201 to 205 input to the sound processor 120-2 are reproduced.

4C is a second listening space of the audio system in which the third virtual sound processor of FIG. 4A is used. Referring to FIG. 4C, the listening space of FIG. 4C is the same as the listening space of FIG. 3C.

The third virtual sound processor 120-3 continuously listens to the 5.1-channel virtual stereo sound in the listening space of FIG. 2C as well as the 5.1-channel in the separate listening space by using the mobile audio receiver 150 that is easy to move. It is used when you want to listen to virtual stereo sound of.

That is, the wired speakers 221 to 223 are disposed in front of the first listening position 250 in the living room, which is the first listening space, and the audio receiver 150 is disposed behind the audio receiver 150 to be a virtual RL speaker. And while using the virtual RR speaker, the audio receiver 150 is moved to the inner room, which is the second listening space, and the audio receiver 150 is disposed in front of the second listening position 260 to virtualize the audio receiver 150. 5.1 channel speakers. Accordingly, both the listener in the living room and the listener in the room enjoy 5.1-channel virtual stereo sound.

The algorithm selecting unit 125 selects which algorithm the virtual sound processor 120 applies to the input audio signal. That is, the listener selects a desired algorithm from the first virtual sound algorithm to the third virtual sound algorithm using the algorithm selector 125, and the virtual sound processor 120 selects the input audio signal from the algorithm selector 125. Apply the virtual acoustic algorithm. As described in FIGS. 4A to 4C, it is also possible to select two or more virtual sound algorithms simultaneously.

The listener selects a virtual sound algorithm optimized for the purpose and arrangement of the audio receiver 150, and the virtual sound processor 120 applies the selected virtual sound algorithm to the input audio signal, thereby making the audio receiver 150 versatile.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

As described above, according to the present invention, a wider sound field and multichannel stereo sound are provided by mounting two speakers in one wireless unit in a wireless audio system and selecting and using an optimized virtual sound algorithm according to the use and arrangement of the speakers. Can be implemented.

The audio receiver may serve as a rear speaker or a front speaker. Thus, the listener can use the audio receiver versatilely by placing the audio receiver in a desired position and selecting the appropriate virtual sound algorithm.

Claims (5)

In an audio system for transmitting and receiving audio signals wirelessly, An audio transmitter configured to generate an audio signal of a plurality of channels having a sound field extended from an input audio signal according to a predetermined virtual sound algorithm, and to transmit the generated multiple channel audio signal according to a WLAN protocol; and And an audio receiver configured to wirelessly receive a plurality of audio signals transmitted from the audio transmitter through RF equipment shared by speakers, and to distribute and reproduce the received plurality of audio signals to corresponding speakers for each channel. Audio system. The method of claim 1, wherein the audio transmitter An algorithm selection unit for selecting a predetermined virtual sound algorithm; A virtual sound processor for generating an audio signal of a plurality of channels having an extended sound field according to a virtual sound algorithm selected by the algorithm selector from an input audio signal; A WLAN modulator for generating a baseband signal of a plurality of channels by modulating the audio signals of the plurality of channels generated by the virtual sound processor according to a WLAN protocol; and And an RF modulator for modulating a baseband signal of a plurality of channels generated by the WLAN modulator into a radio frequency (RF) signal of a plurality of channels. The method of claim 2, wherein the virtual sound processor And a virtual acoustic algorithm for generating an audio signal of an RL channel and an RR channel as an audio signal of two channels having an extended sound field among the input audio signals. The method of claim 2, wherein the virtual sound processor And a virtual acoustic algorithm for generating an input audio signal as a two-channel audio signal having an extended sound field. The method of claim 1, wherein the audio receiver An RF demodulator for demodulating a plurality of channel audio signals transmitted from the audio transmitter to extract baseband signals of a plurality of channels; A WLAN demodulator for demodulating the baseband signals of the plurality of channels extracted by the RF demodulator according to a WLAN protocol; and And a speaker for reproducing an audio signal of a corresponding channel among the audio signals of the plurality of channels demodulated by the WLAN demodulator.

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