Surround sound system and method therefor

FIELD: physics, acoustics.

SUBSTANCE: invention relates to a surround sound system. multi-channel spatial signal comprising at least one surround channel is received. Ultrasound is emitted towards a surface to reach a listening position via reflection of said surface. The ultrasound signal may specifically reach the listening position from the side, above or behind of a nominal listener. A first drive unit generates a drive signal for the directional ultrasound transducer from the surround channel. The use of an ultrasound transducer for providing the surround sound signal provides an improved spatial experience while allowing the speaker to be located, for example, in front of the user. An ultrasound beam is much narrower and well defined than conventional audio beams and can therefore be better directed to provide the desired reflections. In some scenarios, the ultrasound transducer may be supplemented by an audio range loudspeaker.

EFFECT: high quality of reproducing audio and high efficiency of the surround sound system.

12 cl, 11 dwg

 

The technical field to which the invention relates

The invention relates to a surround sound system, and in particular, but not exclusively, to the surround sound system in home theater.

The level of technology

In recent years, providing a spatial sound from more than two channels have become more and more popular, as evidenced, for example, the widespread popularity of the various surround sound system. For example, the growing popularity of home theater systems has led to the fact that the surround-sound system are a common phenomenon in many private homes. However, the problem with conventional surround sound systems is that they require a large number of individual speakers positioned in appropriate places.

For example, a typical system Dolby 5.1 surround sound requires right and left rear speakers, and front center, left and right speakers. Besides can be used low-frequency subwoofer.

A large number of speakers not only increases cost, but also leads to reduced usability and increased inconvenience for users. In particular, is usually considered a disadvantage that the speakers in different positions in front and behind the listeners. Rear speakers are especially problematic because neo is required wiring and physical impact, they have on the interior.

To mitigate this problem, the study aimed at creating sets of speakers that are suitable for play or simulate surround sound system, but use a reduced number of provisions of the speakers. These sets of speakers using directional sound radiation to direct sounds in directions that will lead to the attainment of a user by reflections from objects in the sound environment. For example, sound signals can be routed so that they reach the listener through reflections from the walls, thereby providing to the user a feeling that the sound comes from the side (or even back) from the listener.

However, such approaches provide a virtual sound sources are less reliable than real sources placed behind the listener, and tend to provide reduced sound quality and incomplete spatial impression. Of course, it is often difficult to precisely direct the audio signals to provide the desired reflections that reach the desired position of the virtual sound source. In addition, the audio signals intended for reception from the back of the user, also strive to achieve the user's direct paths or alternative nepredusmotritelen, through this degrading spatial impression.

So would be useful superior Bose surround sound system, and in particular, would be a useful system that will make possible a simplified implementation, simplified configuration, a reduced number of speakers, enhanced spatial impression, superior sound quality and/or improved performance.

Disclosure of invention

Accordingly, the invention preferably seeks to mitigate, the weakening or elimination of one or more of the above-mentioned disadvantages singly or in any combination.

In accordance with an aspect of the invention provides a surround sound system, comprising: a circuit for receiving multi-channel surround signal containing at least one channel environment; directional ultrasonic transducer for emitting ultrasound in the direction of some surfaces to achieve the listening position by reflection from the surface; and a first control circuit for forming a first control signal for the directional ultrasonic transducer of the surround channel signal environment.

The invention can provide enhanced surround sound system. In particular, the system may provide a source virtual volume is Vuka, without requiring the location of the dynamics behind or to the side of the listener, and can reduce the number of speakers or speakers in the system. Superior source virtual surround sound can be provided in the form of highly directional ultrasonic signal, which is used instead of the normal signal in the range of audio frequencies, which cannot be controlled in the same way. The approach can provide reduced spatial deterioration due to unforeseen trajectories signal from the directional ultrasonic transducer to the listener. For example, a directional ultrasound transducer can be placed in front of the listener, but rejected from the listener to the wall for reflection. In such a scenario, a much smaller and often insignificant amount of sound will be perceived as coming from the actual position directional ultrasonic transducer. In particular, it is possible to achieve a much more narrow and well-defined sound beam for forming a virtual surround sound through this allowing you to form an improved management and enhanced spatial impression.

The invention and many variations may not allow simple operation and implementation. Cheap surround sound can be achieved in mn the other scenarios.

The channel environment can be any spatial channel, which is not the front channel. In particular, it can be any channel that is not the front left channel, right front channel, or the front center channel. The channel environment can be, in particular, the channel for playback using the audio source from the side or behind the listener, and in particular, a channel designed to play with the angle more than 45° relative to the direction in front of the Central direction (for example, corresponding to the direction from the listening position to the position of the speaker front center channel).

Directional ultrasonic transducer can be placed in front of the listener. In particular, a directional ultrasonic transducer can be positioned with an angle less than 45° relative to the direction in front of the Central direction (for example, corresponding to the direction from the listening position to the position of the speaker front center channel). Directional ultrasonic transducer can be, for example, not farther away than the position of the front left speaker and the position of the right front speaker, respectively.

The surround sound system further comprises a loudspeaker voice band; and the second with the it management for forming a second control signal for a loudspeaker of the audio band of the surround signal.

This may provide improved performance in many embodiments, implementation and can provide, in particular, improved sound quality in many scenarios. Directional ultrasonic transducer and loudspeaker range of sound frequencies can interact to provide, for example, the best sound quality and/or increased sound level. Loudspeaker range of sound frequencies in many applications can provide, in particular, superior sound quality at a low frequency. Directional ultrasonic transducer and loudspeaker range of sound frequencies can interact to provide improved joint orientation and sound quality for a channel surround sound.

The sound of the directional ultrasonic transducer can provide the basic spatial labels to the user, whereas loudspeaker range of sound frequencies can provide superior sound quality by providing better quality of sound than is typically available from a directional ultrasonic transducer, especially at low frequencies.

Directional ultrasonic transducer and loudspeaker range of sound frequencies, in particular, can be combined. For example, the centers of the directed ultrasonic transformed is the Converter and loudspeaker range of sound frequencies can be within 1 meter or for example, 50 cm from each other. Directional ultrasonic transducer and loudspeaker range of sound frequencies can be combined in a single body of the speaker. In some embodiments, the implementation axial direction for directional ultrasonic transducer and loudspeaker range of sound frequencies can be at an angle to each other (for example, 10°). This may allow improved direction of the ultrasonic signal to the surface to, for example, to reach the listener from the side or rear areas, while providing a more direct path for the signal from the loudspeaker of the audio band.

Loudspeaker range of sound frequencies can be, in particular, a conventional audio speaker, for example, an electrodynamic loudspeaker (usually a forward propagation). Loudspeaker range of sound frequencies, in particular, may have an operating frequency range below 10 kHz. This can occur for scenarios in which the loudspeaker audio frequency is used only to Supplement the directional ultrasonic transducer when the volumetric representation of the signal. However, in scenarios, for example, when the loudspeaker of the audio frequency should also be used for other purposes (for example, represent the pressure of the rear channel), the operating frequency range can be extended to higher frequencies.

The surround sound system further comprises a delay circuit for introducing a delay of the second component signal, the second control signal arising from the volume of the signal relative to the first component signal in the first control signal arising from the volume signal.

This can provide improved performance and may in particular provide improved spatial perception, meaning that the surround signal more clearly perceived as coming from the direction of the ultrasonic signal that is reflected from a direction which usually can be located on the side, behind or above the listener. The delay may be, in particular, such that the signal from the directional ultrasonic transducer is made up of a signal from the loudspeaker, audio frequency, thereby providing more spatial labels.

The approach can use the precedence effect or Haas to provide enhanced spatial impression and improved directional perception of surround sound, while maintaining high sound quality. The delay may be, in particular, in the interval from 1 MS to 100 MS.

The delay is not more than 40 MS exceeds the delay difference in tract the MII transmission between the transmission path from the directional ultrasonic transducer to the listening position and the direct path from loudspeaker range of sound frequencies to the listening position.

This can provide improved performance and may in particular, to provide a surround signal, which is perceived as a single source in the direction of a received ultrasonic signal. Thus, this may allow the directed ultrasonic transducer and loudspeaker range of sound frequencies to appear as a single loudspeakers, mounted in the direction of which is an ultrasonic signal. In some embodiments, the implementation of improved performance can be achieved for the corresponding relative delay of less than 16 MS or less 5 MS.

According to an optional characteristic of the invention, the delay circuit is configured to change the delay in response to the delay in the transmission path, and the delay in the transmission path specifies the delay of the transmission path from the directional ultrasonic transducer to the listening position.

This can provide improved performance and may in particular, to create a three-dimensional signal, which is perceived as a single source in the direction of a received ultrasonic signal. Thus, this may allow the directed ultrasonic transducer and loudspeaker range of sound frequencies to appear as a single Gro is logowriter, set in the direction of which is an ultrasonic signal. By changing the delay for a better match with the value of delay in the transmission path can be improved spatial perception and the single source.

The delay in the transmission path can be determined, for example, by measurements (e.g., using a microphone at the listening position) or may be calibrated, for example, manually by the user indicating the distance from loudspeaker range of sound frequencies to the listening position.

According to an optional characteristic of the invention, the delay circuit is configured to change the delay in response to the value of the position of the sound source.

The delay may vary for the regulation of spatial perception, which must be determined by the signals from the loudspeaker of the audio frequency and directional ultrasonic transducer. In particular, spatial labels, provided the two signals may be combined to provide a spatial perception of the direction of the sound source between the direction of the loudspeaker, audio frequency and direction of arrival of the reflected ultrasonic signal.

In accordance with fakultativprotokoll of the invention, the first frequency range bandwidth for the formation of the first control signal from the surround signal differs from the second frequency range bandwidth for the formation of the second control signal of the surround signal.

This can improve the sound quality in many scenarios and may, in particular, be used to provide the listener an improved and more uniform combined signal.

According to an optional characteristic of the invention, the upper cutoff frequency for the first frequency range bandwidth above the upper cutoff frequency to the second frequency range bandwidth.

This can improve the sound quality in many scenarios.

According to an optional characteristic of the invention, the second control circuit includes a low pass filter.

This can improve the sound quality in many scenarios. In many scenarios, the low pass filter can mainly have the top (e.g., 6 dB) cutoff frequency in the range from 600 Hz to 1 kHz, or specifically in the range from 750 Hz to 850 Hz.

According to an optional characteristic of the invention, the second control circuit additionally has a capability of forming a second control signal of the front channel multichannel surround signal is La.

This can provide improved and/or less complex system of surround sound and many variations of implementation. In particular, it may allow the use of a reduced number of speakers, as the same speaker can be used for front channel and additions directional ultrasonic transducer while providing a channel environment. The front channel can be, in particular, the front left, front right or front Central channel.

According to an optional characteristic of the invention, the surround sound system further comprises means for changing the axial direction of the directional ultrasonic transducer relative to the axial direction of the loudspeaker of the audio band.

This may provide improved performance in many scenarios and may, in particular, to provide an improved spatial impression by allowing the optimization direction of the ultrasonic signal, to provide the best reflected path, allowing the loudspeaker frequencies of sound to reach the listener on a straight path. Means for changing the axial direction may be a scheme to modify the axial direction.

According to an optional characteristic of the invention, the system about the roadways to sound further comprises a circuit for receiving the measurement signal from the microphone; and a scheme for adapting the level of the second component signal, the second control signal arising from the volume of the signal relative to the first component signal in the first control signal arising from the surround signal, in response to the measuring signal.

This may provide improved performance in many scenarios and may, in particular, to provide an improved sound quality. In particular, this may allow a smoother transition between the frequency range, primarily supported by the loudspeaker of the audio frequencies, and frequency range, mainly supported by focused ultrasonic transducer.

According to an optional characteristic of the invention, the normalized ratio of the compensated delay between the second component of the signal in the second control signal arising from the surround signal, and the first component of the sound signal in the first control signal arising from the volume signal is not less than 0,50.

This can provide improved performance and/or reduced complexity in some embodiments, implementation. In some scenarios, the first and second signal components can be virtually identical. Delay compensation can compensate, in particular, the deliberate delay of the WTO is th component of the signal relative to the first component of the signal. Delay compensation may correspond to detect the highest correlation with compensated delay (delay variation). The ratio can be normalized with respect to amplitude, power and/or energy of the first and/or second signal components.

According to an optional characteristic of the invention, the surround sound system further comprises a circuit for receiving the measurement signal from the microphone; and a scheme for adapting the axial direction of the directional ultrasonic transducer in response to the measuring signal.

This may provide improved performance in many scenarios and may, in particular, to provide an improved spatial impression by allowing the optimization direction of the ultrasonic signal, to ensure the listener is best reflected path.

In accordance with an aspect of the invention provides a method of operation for a surround-sound system.

These and other aspects, features and advantages of the invention will become apparent and will be explained with reference to variant (variants) described below.

Brief description of drawings

Embodiments of the invention will be described only as an example with reference to the drawings, in which

Figure 1 - illustration of a configuration of a speaker system for a conventional si themes surround sound;

Figure 2 - illustration of an example system setup speaker surround-sound system in accordance with the invention;

Figure 3 - illustration of an example system elements surround sound in accordance with the invention;

Figure 4 - illustration of an example of elements of a control circuit of the surround sound system in accordance with the invention;

Figure 5 - illustration of an example of elements of a control circuit of the surround sound system in accordance with the invention;

6 is an illustration of an example system setup speaker surround-sound system in accordance with the invention;

Figa is an illustration of an example circuit the frequency domain the dynamic amplification, for which the small amplitudes of the frequency separation is chosen as low as possible;

Figv is an illustration of an example circuit the frequency domain the dynamic amplification, for which the frequency separation is increased to allow greater output SPL;

Figa is an illustration of the representation in the frequency domain approximate way to create a psychoacoustic optimal dynamic gain settings with small amplitude; and

Figv is an illustration of the representation in the frequency domain approximate way to create a psychoacoustic optimal dynamic gain settings with a large amplitude;

Figure 9 - illustration of an example of elements stored is the surround-sound system with dynamic amplification in accordance with the invention.

The implementation of the invention

The following description focuses on embodiments of the invention, applicable to the surround sound system with five spatial channels. However, you will need to take into account that the invention is not limited to this application but may be applied to many other systems, surround sound, including, for example, systems with seven or more spatial channels.

Figure 1 illustrates the system configuration of the speakers in the usual five-channel surround sound, for example, the home theater system. The system contains a Central speaker 101, forming the center front channel, a left front speaker 103, forming a left front channel, right front speaker 105, forming a right front channel, left rear speaker 107, forming a left surround channel and the right surround speaker 109, forming a right surround channel. Five speakers 101-109 together provide the spatial perception of sound in position 111 listen and allow the listener to obtain three-dimensional and multidirectional sound impression. In many systems, home theater system can additionally include a subwoofer for low frequency effects channel (LFE).

The requirement for the location of the speakers on the side or back of the state is listening to is usually considered very bad, because it not only requires the placement of additional loudspeakers in uncomfortable positions, but also requires them to connect to the excitation source, which is typically a power amplifier home theater. In a typical system configuration is necessary that the wires coming from provisions 107, 109 district loudspeakers to the amplifier unit, which is usually located closer to the front speakers 101, 103, 105. This is particularly disadvantageous for product type home theater systems, which tend to have broad appeal and application in environments that are not optimized or designed for sound impressions.

Figure 2 illustrates an example configuration of a speaker system in accordance with some variations of the embodiment of the invention. In the example, the front speakers, namely the left front loudspeaker 103, the center speaker 101 and the front right loudspeaker 105, form the audiogram in front of the provisions 111 listening. However, in the system of figure 2 the surround sound signals are not provided with separate loudspeakers, mounted to the rear of the user, and provided speakers 201, 203, installed in front of the provisions 111 listening. In the specific example left the district speaker 201 is located on the left front Dinamika, and the right of the district speaker 203 is located near the right front speaker 105.

In the example district speakers 201, 203 made with the possibility of emission of a sound signal 205, 207, which is reflected side walls 209, 211 and the rear wall 213 to reach the position 111 listen to from the rear direction from the listener. Thus, the rear circumferential dynamics 201, 203 form the surround signals 205, 207, which seem to the listener emerging from behind. This effect is achieved by radiation rear sound signals 205, 207 in such a way that they are reflected by walls 209, 211, 213. In a specific example, the signals 205, 207 surround sound reaches the listening position by means of reflections from two walls, namely the side walls 209, 211 and the rear wall 213. However, you will need to take into account that other variants of implementation and scenarios may include fewer or more reflections. For example, the volume signals 205, 207 may radiate to achieve position 111 listening using a single reflection from the side walls 209, 211, thereby creating a perceived virtual sound source on the side of the user.

However, in the system of figure 2, the signals 205, 207 surround sound are not the usual audible sound signals, but rather, are emitted in the form of ultrasonic signals. Thus, ICI, the EMA applies ultrasonic loudspeaker, which emits ultrasonic signals 205, 207 surround sound.

Such ultrasonic transducers have a highly directional sound beam. In General, the orientation (narrowness) of the loudspeaker depends on the size of the speaker compared to the wavelength. Audible sound has a wavelength varying from a few inches to several feet, and because these wavelengths comparable to the size of most loudspeakers, the sound is normally distributed Omni-directional. However, for the ultrasonic probe wavelength is much smaller, and accordingly, it is possible to create the source of the sound, which is much more of the emitted wavelengths by coming to the formation of a very narrow and highly directional beam.

This highly directional beam can be much better to manage, and in the system of figure 2 it can be directed into position 111 listening through well-defined reflections from the walls 209-213 premises. The reflected sound reaches the ears, giving the listener the perception of the presence of sound sources located at the rear of the premises. Similarly, in the direction of the ultrasonic beam in the lateral wall or ceiling it is possible to form the perceived sound source side and top of the listener, respectively.

Thus, the system of figure 2 uses ultra audible Converter, which has a very directional sound beam, as or as part of a district speaker 201, 203, which are arranged in front of the provisions 111 listening. This ultrasonic beam can be easily directed into the side or rear wall 209-213 premises, so that the reflected sound reaches the listener's ears to ensure the perception of the presence of sound sources placed in the back part of the room.

Ultrasonic signals 205, 207 are formed, in particular, by means of amplitude modulation of the ultrasonic carrier signal with the audio signal of the channel environment. This modulated signal is then radiated from district speakers 201, 203. The ultrasonic signal is not perceived by the listener directly, but modulating the audio signal can automatically be audible without the need for any special functionality, receiver or hearing AIDS. In particular, any nonlinearity in the path of sound from the transducer to the listener can act as a demodulator, thereby recreating the original sound signal, which is used for modulating an ultrasonic carrier signal frequency. This nonlinearity may occur automatically in the transmission path. In particular, the air as a transmission medium by nature manifests Neli is anou characteristic, what causes the ultrasound becomes audible. Thus, in the example, the nonlinear properties of the air cause the sound demodulation of the ultrasonic signal of high intensity. Thus, the ultrasonic signal can be automatically demodulate, to ensure the listener audible sound. Alternatively or additionally, the nonlinearity can be provided by additional means. For example, tonal ultrasonic signal can also be transmitted to the listening position (for example, from top to ensure a relatively limited listening area). Mixing the two ultrasonic signals can then lead to demodulation and reproduction of the audio signal.

For examples and further description of the use of ultrasonic transducers for sound radiation can be found, for example, in thesis "Sound from Ultrasound: The Parametric Array as an Audible Sound Source" authored by F. Joseph Pompei, 2002, Massachusetts Institute of technology.

The use of ultrasonic radiation in the channels of the environment provides a very narrow beam. This helps to better define and manage the reflections and may, in particular, to provide more precise control of the angle of arrival at the listening position. Thus, the approach may allow much better to set and manage virtual vos is minimimum position surround sound sources. In addition, the use of ultrasonic signal can afford to accept such a position closer to a point source, i.e. less blurred. Also a narrow beam ultrasonic transducer reduces the emission of sound for other trajectories, and in particular, reduces the level of sound from any sound reaching the listening position in a straight path.

Accordingly, the described approach provides a much better position specified virtual surround sound, which should be perceived by the user. In particular, spatial label directions provided to the listener, significantly more accurate and more uniform and consistent with the position of the sound source behind (or on the side of the listener).

In the specific example district speakers 201, 203 do not contain only the ultrasonic transducer or not radiate only ultrasonic signals. On the contrary, each district speakers 201, 203 contains the layout of the speakers, which includes a directional ultrasonic transducer for emitting ultrasound in the walls 205, 207, and loudspeaker range of sound frequencies, which radiates sound in the range of audio frequencies (e.g., 5-10 kHz).

In particular, the quality of the audible sound, deriving from the use of such an ultrasonic approach is in, in some embodiments, implementation and scenarios is not optimal, because the process by which the demodulated ultrasonic carrier to make a modulating audio signal is audible, is inefficient and is inherently nonlinear. Ultrasonic speakers therefore have the tendency to create typically suboptimal sound quality, and strive to have a low maximum power, thereby complicating the production of high levels of sound.

In the system of figure 2, this effect is mitigated by the ultrasonic transducer, complemented by an electrodynamic loudspeaker front propagation, which is optionally emits some sound from a channel environment. This radiation signal in the range of audio frequencies can reach position 111 listening in a straight trajectory. Thus, in addition to the reflected ultrasonic signals 205, 207 district speakers 201, 203 can also generate signals 215, 217 in the range of audio frequencies, which, in particular, can reach the listener along a straight path.

Thus, in the system the sound of the left channel environment that is perceived by a listener at position 111 listening is a combination of the demodulated ultrasonic signal 205 and the direct signal 215 in the range zvukovoy the frequencies. Similarly the sound of the right channel environment that is perceived by a listener at the listening position is a combination of the demodulated ultrasonic signal 207 and the direct signal 217 in the range of audio frequencies.

The use of loudspeaker range of audio frequencies to complement a directional ultrasonic transducer provides superior sound quality and many variations of implementation. In particular, it can provide superior quality of sound at low frequencies. Such low frequencies are generally not able to provide as much spatial labels as the upper frequencies, and so the listener can still perceive the surround sound coming from the rear, then there may still perceive that behind there is a virtual sound sources.

However, in the specific embodiment of figure 2 the signal surround sound radiated from the loudspeaker, audio frequency, moreover, is delayed relative to the signal surround sound radiated from a directional ultrasonic transducer. Thus, in the example introduces the delay of the sound in the loudspeaker of the audio frequencies relative to the ultrasonic signal, to ensure that you can save the sound coming only from the direction of the reflected ultrazvukovoy.

This approach is based on psychoacoustic phenomenon known as the "precedence effect" (also called "Haas effect" or the "law of the first wavefront"). This phenomenon indicates that when the same audio signal is received from two sources in different positions and with sufficiently low latency, the sound is perceived only coming from the direction of the sound source that is located in the front, i.e. from the first incoming signal. Thus, the psychoacoustic phenomenon refers to the fact that the human brain receives the majority of spatial labels of the first received signal components.

Therefore, the result of additions directional ultrasonic transducer cooperating loudspeaker range of sound frequencies is that achieved convincing, stable perception of a sound source in the place of reflection, at the same time providing high-quality sound that is typically associated with a conventional loudspeaker.

In some embodiments, the implementation of the directed ultrasonic transducer and classic loudspeaker can reproduce the same parts of the audio frequency of the emitted signals, that is, the raw input signal surround sound (except for the delay applied to the loudspeaker dia is Altanbulag sound frequencies) can radiate from both sources. In other embodiments, the implementation of the directed ultrasonic transducer and loudspeaker range of sound frequencies can be reproduced, for example, different, possibly overlapping parts of the frequency range of the input signal, so as to further improve the stability of spatial illusion.

Figure 3 illustrates an example layout of the district of speakers and associated functionality excitation in accordance with some variations of the embodiment of the invention. For clarity and brevity, the example will be described relative to the left channel environment of example 3. However, you will need to take into account that the example and principles are equally applicable to the right channel environment or in fact to any channel environment.

Figure 3 illustrates the receiver 301, which receives multi-channel surround signal, for example, 5.1 surround signal. Multi-channel surround signal can be, for example, a set of analog signals with one sound signal for each channel, or may be encoded in digital form of multi-channel surround signal. In the latter case, multi-channel surround signal can be encoded, and the receiver 301 may be configured to decode this signal.

You will need to take into HV the housing, that multichannel surround the signal may be received from any suitable source, such as an external or internal source.

Multi-channel surround signal contains at least one channel environment. In particular, multi-channel surround signal contains one or more of the front channels (in the specific example - three front channels), which are intended for presentation to the listener from the forward direction. Moreover, included at least one channel environment, which is associated with the position of the sound source from the side or behind the listener. Thus, the channel environment is associated with the position of the sound source that is not a forward position, and in particular, beyond the angle formed (extreme) left and (extreme) right front speakers. In the specific example multi-channel surround signal contains two channel environment, namely, the left surround channel and the right surround channel.

3 additionally illustrates the processing of a single channel environment. In particular, figure 3 illustrates the elements of the functionality associated with the position of the left rear speaker.

The receiver 301 is connected to the first control unit 303, which is connected with directional ultrasonic transducer 305 and which can form the encoded control signal for him. In addition, the receiver 301 is connected with the second control unit 307, which is connected with the loudspeaker 309 range of sound frequencies and which can generate a control signal for him. Thus, in the example, the received signal of the left rear channel environment is filed in the first circuit 303 and the second control circuit 307 controls. Circuit 303, 307 manage accordingly directed ultrasonic transducer 305 and loudspeaker 309 range of sound frequencies, so that the left surround channel environment is radiated from a directional ultrasonic transducer 305 and the loudspeaker 309 range of sound frequencies, that is, and how ultrasonic signal and a sound signal.

In some embodiments, the first circuit 303 controls may simply contain ultrasonic modulator, which modulates the left rear audio signal to the ultrasonic carrier frequency, followed by a power amplifier, which amplifies the signal to a suitable level for the directional ultrasonic transducer 305 to form a suitable level of sound output. In typical applications of ultrasonic carrier frequency greater than 20 kHz (e.g., 40 kHz), and the sound pressure level exceeds 110 dB (often about 130-140 dB).

The second circuit 307 controls may simply contain approach is ASI power amplifier, which directly excites the speaker 309 range of sound frequencies.

Thus, essentially the same audio signal may be fed into a directional ultrasonic transducer 305 and the speaker 309 range of sound frequencies. In particular, the ratio between the components of the audio signal from the output signals of the first circuit 303 controls and speaker 309 audio frequency can be quite high, and in particular, the normalized energy ratio may be above 0.5. In scenarios in which the sound signals of the two circuits 303, 307 management are delayed relative to each other, the ratio can be determined after payment of such delay. The ratio can be determined, in particular, in the form of maximum correlation between the audio signals in the control signals of the two circuits 303, 307 control.

However, in other embodiments, the first circuit 303 management and/or the second circuit 307 controls may include processing that leads to the components of the audio signal that is processed differently in the two trajectories. In particular, as mentioned earlier, the audio signal to the loudspeaker 309 range of sound frequencies may be delayed and/or filtered.

Figure 4 more clearly illustrates an example of the second circuit 307 controls, to ora contains the operations of the delay and filtering. In the example, the first surround signal is delayed in block 401 delay, and then filtered in the filter 403 low frequencies. The delayed and filtered by the low frequencies of the audio signal is then fed into the amplifier 405 power, which amplifies the signal to a suitable level for a loudspeaker 309 range of sound frequencies.

Thus, in the example to the signal for a loudspeaker 309 audio band adds a time delay to ensure that the listener perceives the whole or a large part of the sound as coming from the direction of the reflected sound beam 205, and not from the direction of the audio signal 215 from the speaker 309 range of sound frequencies. The result is a compelling, sustainable perception of a sound source in place of the reflection from the rear wall 213, but with improved sound quality from the speaker 309 range of sound frequencies.

This effect precedence (or Haas) occurs when two speakers emit the same signal, but with one signal with a short delay relative to another. The effect usually occurs for a relative delay in the range from about 1 MS to the upper limit, usually 5-40 MS. In this situation, the sound is perceived coming from the direction of nesuderinama loudspeaker. The upper limit depends on the type of signal the Smallest value of about 5 MS valid for very short sounds like a click or push whereas for speech are large values up to 40 MS. If the delay is increased beyond the upper limit, the perceived fusion of sound sources in position nesuderinama source already does not occur, and the two sources are treated separately (echo). On the other hand, if the delay is less than the lower limit of the precedence effect (about 1 MS), then there is a "summing localization, and a single source of sound is perceived in position between the two sources.

In the example, the delay is set such that the signal from the directional ultrasonic transducer 305 is taken a little earlier signal from the speaker 309 range of sound frequencies.

In order to achieve the optimum effect of precedence, delay should be set very carefully, and in particular, the second circuit 307 controls need to apply a delay τ, which contains two elements. The first delay element τt1compensates for the difference in travel time due to the different lengths of the trajectories to the listener's ears for the sound waves originating from a directional ultrasonic transducer 305 and the loudspeaker 309 range of sound frequencies, respectively. As is clear from figure 2, the delay in the transmission path corresponds to a distance from the directional ultrasonic transducer 305 to the point of reflection on bomwollen 209 (D U1) plus the distance from the reflecting point on the rear wall 213 to the reflecting point on the side wall 209 (DU2) plus the distance from the reflecting point on the rear wall 213 to position 111 listening (DU3). The difference between the distances can then be found by subtracting the length of the path from the loudspeaker 309 range of sound frequencies to position 111 listening (DC). This difference in distances respectively equal to DU1+DU2+DU3-DCand to compensate for it, the necessary delay τt1=(DU1+DU2+DU3-DC)/c seconds (c is the speed of sound).

The use of this delay causes the reflected sound from the directional ultrasonic transducer 305 and the direct sound from the loudspeaker 309 range of sound frequencies simultaneously arrive at the listener's ears. In addition to this, a compensating delay to achieve the effect of precedence required additional delay element τt2. The total delay applied to the signal of the loudspeaker 309 range of sound frequencies respectively equal to τ=τt1+τt2.

As mentioned earlier, the value of τt2not very important, provided that it is between 1 MS and the upper limit of the precedence effect, which depends on the signal type.

For the most important type of signal, short clicks, the top within the for τt 2equal to 5 MS, and therefore, in some scenarios it may be useful to choose the delay τt2in the range of 1-5 MS. This delay can be used, for example, in scenarios in which you can thoroughly customize the configuration, where the delay in the transmission path is well known and static.

However, the desired value for compensating the delay τt1(the delay in the transmission path) is very dependent on the geometric layout of the room, placement of the loudspeakers and the listening position, and in typical configurations is in the range from several to several tens of milliseconds (e.g., 3-30 MS). This means that for a small value of τt2between 1-5 MS total required delay τ is significantly determined the exact value of τt1and it is necessary to carefully set the value of τt1to match the actual geometric configuration.

In some embodiments, the implementation of block 401 delays, respectively, may be delayed, which may vary in response to the delay value in the path transmission path transmission from the directional ultrasonic transducer 305 to position 111 listening. The delay value in the path for the directional transmission of the ultrasonic transducer 305 can be reduced by the delay value in the path before the Chi for the transmission path from the loudspeaker 309 range of sound frequencies to the position 111 listening through this shaping is the difference of the delay in the transmission path, which is used to bias when you change the path.

Compensation for delays in the transmission path can be performed manually by the user, for example, by setting manually the relative delay in the transmission path τt1. This setting can be based, for example, on the measurement of two physical lengths of the trajectories by the user, or on the need for the user to manually adjust the delay control up until not perceived the desired effect.

As another example, the microphone can be placed in position 111 listen and connect with the functionality of a control. The measuring signal from the microphone can then be used to configure the block 401 delay so that he compensated the delay difference in the transmission path, and provide the desired effect precedence. For example, the remote distance measurement can be performed by radiation calibration signals from directional ultrasonic transducer 305 and the loudspeaker 309 range of sound frequencies.

Thus, in the described example, the system is designed with the possibility of introducing a delay period that is not more than 40 MS exceeds the delay difference in the transmission path between the trajectory is peredachi from directional ultrasonic transducer 305 to position 111 listening and trajectory from the speaker 309 range of sound frequencies to the position 111 listening. Of course, there are many ways of implementing the delay is mostly not more than 15 MS or 5 MS exceeds this delay difference in the transmission path. Actually this can be achieved through calibration and adaptation of the system based on the determination of the difference between the delay in the transmission path, and/or can be achieved by adjusting the location of the speakers to the specific characteristics of the premises.

To make the system less sensitive to the actual geometric configuration and to provide a stable localization in the direction of the reflected sound from the directional ultrasonic transducer 305 in a large range of use cases, in some embodiments, the implementation may be preferable to set the value of τt2relatively high. The advantage of this approach in many scenarios is that in most cases will not need to set the delay τt1in accordance with the specific configuration, that is, the same delay will be suitable for relatively strong fluctuations in the difference of the delay in the transmission path. However, since τt2you can install more than 5 MS, the effect of precedence may not work fully for very short signals, such as navigation (links) in percussion music.

However, in the example, the second circuit 307 control also contains a filter 403 low frequencies, which filters out low frequency signal in the audio frequency before it is fed into the loudspeaker 309 range of sound frequencies. Thus, in the example, the speaker 309 range of sound frequencies is mainly used to play the lower part of the frequency spectrum surround signal, whereas high-frequency part of the spectrum, including transitions, mainly reproduced directional ultrasonic transducer 306.

Thus, in the example vary the bandwidth of the first circuit 303 and second control circuit 307 controls.

Cutoff frequency of the filter 403 low frequencies can be set low enough to effectively filter the navigation of the sound radiated from the speaker 309 range of sound frequencies, thereby alleviating the requirement to delay for the effect of precedence. However, it can optionally be set high enough to ensure that there is no gap between the highest frequency, which effectively reproduced by the loudspeaker 309 range of sound frequencies, and the lowest frequency, effectively reproduced directional ultrasonic transducer 305. Of course, since ultrasonic transducers often have poor frequency response at the bottom is their frequency, it is possible to effectively adjust the cutoff frequency to ensure a smooth transition.

Practical experiments have shown that in a typical configuration, a living room and with different types of music as input signals very satisfactory results can be achieved when the value of τt2in 10 MS and LPF corner frequencies 800 Hz.

In some embodiments, the implementation of the transition between the directional ultrasonic transducer 305 and loudspeaker 309 audio frequency can be controlled by a suitable filter of low frequencies on the basis of known characteristics of a directional ultrasonic transducer 305 and the loudspeaker 309 range of sound frequencies, it is possible to make a static characteristic of the transition.

However, since the transition is perceived at the listening position may depend on changes in these characteristics, as well as the characteristics of a specific environment, in some embodiments, the implementation of the transition can be adapted based on the feedback mechanism.

For example, the measurement signal from the microphone located at position 111 listening, can be used for adaptation of the transition. In particular, the signal level for the directional ultrasonic transducer 305 relative to the speaker 309 range of sound frequencies which can be regulated on the basis of the microphone signal. Alternatively, or additionally, you can adjust the cutoff frequency of the filter 403 low frequencies.

As an example, the second control unit 307 may receive a signal of a microphone. He can analyze it to determine the signal level in the frequency range below the cutoff frequency (for example, 500 Hz to 700 Hz) and the signal level in the frequency range above the cutoff frequency (for example, 900 Hz to 1100 Hz). If the signal in the lower frequency range below the level of the signal in the upper frequency range, the gain in the amplifier 405 power and/or cutoff frequency in the filter 403 low frequency may increase, leading to increased signal level from the speaker 309 range of sound frequencies. On the contrary, if the signal in the lower frequency range above the level of the signal in the upper frequency range, the gain in the amplifier 405 power and/or cutoff frequency in the filter 403 low frequencies can be reduced, leading to reduced signal level from the speaker 309 range of sound frequencies.

In some embodiments, the implementation of the delay provided by unit 401 of the delay can be set to be a consequence of the perceived spatial position of the sound source, which does not correspond to the direction of arrival of the reflected signal, but rather corresponds to a position between etimological and position of the speaker 309 range of sound frequencies. In particular, there can be provided the value of the position of the sound source, which indicates the desired position between these points, and the second control unit 307 may proceed to the appropriate installation delays.

This can be achieved, in particular, by setting the delay τt2in a value between 0 and 1 MS. In this case, you get the perception of "summing localization" instead of the precedence effect. This will lead to perceived source between the directions of the reflected ultrasonic beam and the loudspeaker 309 range of sound frequencies. Therefore, by adjusting the delay you can control the position of the perceived virtual source similar to normal stereo playback. Such embodiments of preferably include an accurate assessment or determining the difference between the delay in the transmission path to ensure correct installation delays.

It should be noted that modern information not obvious that the effect of precedence will work in situations where the detainees and nezagarionnyje loudspeakers reproduce the different parts of the frequency spectrum of the signal. Rather, psychoacoustic the doctrine of the precedence effect is limited to the situation in which the same signal is emitted from two sources. However, practical experiments what s made almost no overlap between the frequency bands, reproduced directional ultrasonic transducer 305 and loudspeaker 309 range of sound frequencies. These experiments showed that the effect of precedence also works if the two sources produce signals, which have different frequency spectrum, but they share the same modulation envelope or similar General temporal characteristics of the signal.

In the example, the speaker 309 range of sound frequencies and directional ultrasonic transducer 305 are placed at an angle to each other, i.e. their axial direction or the main propagation direction are at an angle to each other. This may provide improved performance in many scenarios and may allow, in particular, focused ultrasonic transducer 305 to transmit the signal directly in the side wall, while allowing the speaker 309 range of audio frequencies to be aimed directly at the position 111 listening. Thus, the district speaker 201 can be calibrated for optimal sound reproduction in different acoustic environments, thereby providing improved sound quality and/or improved spatial impression.

In some embodiments, the implementation of the axial direction of the directional ultransonographically 305 may be changed relative to the axial direction of the speaker 309 range of sound frequencies. In some embodiments, the implementation of this change can be done manually. For example, the listener may be secured by means of the direction of the directional angle of the ultrasonic transducer 305 so that the ultrasonic beam can be directed at the point of reflection side wall that provides optimum reflection to achieve the listening position.

In some embodiments, the implementation of the direction of at least one of the directional ultrasonic transducer 305 and the loudspeaker 309 audio frequency can be set by calibration circuit with feedback. For example, the control unit can be connected with a microphone in position 111 listening and can't take from him the measured signal. This can be used to control the directional angle of the ultrasonic transducer 305, and thus the reflection points on the walls 209, 213. The calibration signal can be submitted in a directional ultrasonic transducer 305 (silent all other speakers), and the direction of the ultrasonic beam can be adjusted until then, until it provides the highest signal level measured by the microphone.

The direction of the ultrasonic beam can be changed electronically (for example, using the technique of forming beam) or, for the EP, by installing a directional ultrasonic transducer 305 hinge mechanism that can be adjusted manually or set in motion with servo motors.

In the example of figure 2, each spatial channel radiates its own separate speaker. However, as illustrated in figure 2, the described approach allows effective surrounding impression along with authorization to dispose of district speakers 201, 203 in front of the user, and in particular, to combine or placed near one of the front speakers 101, 103, 105. However, it also allows the same dynamics be used to play more than one of the spatial channels. Thus, in many embodiments, the implementation of the district speakers 201, 203 may also be used for visualization of one of the front channels.

In the specific example left the district speaker 201 can also play the left front channel, and the right of the district speaker 203 can also play right front channel. However, since the front left and right channels should be delivered directly to the listening position (a straight path), so they seem to be coming from the front, i.e. directly from the speaker, the front channel is reproduced only from the speaker 309 range of sounds the x frequency instead of directional ultrasonic transducer 305.

This can be achieved, in particular, by generating a control signal for a loudspeaker 309 range of sound frequencies not only of the signal of the left channel environment, but also from the left front channel. Figure 5 more clearly illustrates how you can modify the second control unit 307 of figure 4 to include a combiner 501, which combines the delayed and filtered at low frequencies left the ring signal from the left front signal. In the example, the multiplexer 501 is inserted between the filter 403, bass, and amplifier 405 power.

Thus, the left front speaker 103 and the right front speaker 105 can be removed, and instead, you can use the loudspeaker 309 range of sound frequencies in the left circuit dynamics 201 and the speaker 309 range of sound frequencies in the district dynamics 203, receiving as a result of 6.

Thus, a very significant advantage of the described approach is that it not only allows you to directly set the speakers to create surround sound, but also allows a reduction in the total number of required loudspeakers.

Alternatively or additionally, the encircling dynamics 203, 205 may also be used for the center channel. For example, instead of (Il is in some scenarios - and) of the front left channel is supplied to a multiplexer 501, it is possible to apply the Central channel. Thus, a speaker 309 range of sound frequencies in the left circuit dynamics 203 can also be used for radiation of the Central channel. The Central channel also may be fed into a multiplexer 501 to the right of the district speaker 205 provided centrally perceived location of a sound signal for center channel emitted from the left and right circumferential speakers 203, 205.

Of course, in some embodiments, the implementation of the system can deliver immersive surround sound using only the district speaker 203, 205, and in particular, the district dynamics 203, 205 can be used to reconstruct left and right channel environment, the left and right front channel and the Central channel.

In some embodiments, the first control unit 303 may be configured to provide a control signal in response to the characteristic signal of at least one other channel of multi-channel surround signal than the at least one channel environment, which is reproduced directional ultrasonic transducer 305. In particular, the control signal may be generated in response to the signal level at one or a few the fir these other channels.

Of course, in many scenarios it is impossible or undesirable to create very high levels of sound using ultrasonic loudspeaker. This may be limited, for example, standards for exposure to ultrasound or practical constraints of implementation. Also the subjective effect of ultrasound may depend on the total time of exposure, which can mainly be limited. Therefore, in some embodiments, the first control signal can be formed, whereas the sound pressure level created by the other sound channels in multi-channel surround signal. Accordingly, the ultrasound generated directional ultrasonic transducer, may be limited to times in which the signal level in one or more other channels corresponds to a certain criterion. In particular, a directional ultrasonic transducer can only be used when the overall volume level is low, thereby ensuring that the focused ultrasonic transducer is limited by the creation of a safe level of exposure to the listener. In particular, sequences with low overall sound pressure level and clear surround sound effects are widespread in sound recording for movies, and op is the sled approach may particularly be suitable, for example, for home theater systems.

Directed ultrasonic transducers 305 inherently have low efficiency and poor frequency response at low frequencies. The main non-linear process through which is formed a sound, can approximately be expressed by the approximation Berktay (Berktay) for the far zone (Berktay, H. O. (1965) Possible exploitation of non-linear acoustics in underwater transmitting applications. J. Sound Vib., (2), 435-461), which establishes that an audible sound is proportional to the second derivative of the squared envelope

,

where- beep, and- envelope.is the beep function that you want to play. The differential of the second order is frequency-dependent function of the gain is proportional towhereis the frequency. This boost function means that for each doubling of frequency ultrasonic loudspeaker is increased by 12 dB.

To ensure high-quality sound from a directional ultrasonic transducer 305 should be applied compensation function to provide a balanced frequency response. To align inherenthung is the need, to the input signal can be filtered with respect to. This filter is equivalent to a low pass filter with a slope of 12 dB.

The choice of point -3 dB cutoff frequency for this filter equalization low frequency determines the maximum achievable sound pressure Level (SPL) sound output for directional ultrasonic transducer. Ceteris paribus directional ultrasonic transducer with boundary frequency at 2000 Hz can be reproduced by 12 dB louder than the focused ultrasound transducer with boundary frequency at 1000 Hz.

As described in the invention, the loudspeaker 309 audio frequency is used for the formation of medium/low frequencies below this cutoff frequency. Ideally, the boundary point of the low frequency will be chosen to be as low as possible frequency. This means that directional ultrasonic transducer provides more sound tags for localization purposes, and the labels localization created by loudspeaker range of sound frequencies is minimized. On the other hand, at low frequencies the sound output directional ultrasonic transducer is low, limiting the maximum SPL output of the system.

Typical directional ultrasonic transducer can dopuskat the maximum sound output of about 70 dB at 1000 Hz. For audio home theater 70 dB may be sufficient to create multidirectional and covering effect. To apply for audio home theater, the maximum amplitude may need to be increased.

You cannot just increase SPL directional ultrasonic transducer, as it quickly would exceed the operating limitations of the transducer and electronics, leading to serious distortion and possible transfer of dangerous levels of ultrasound. In order to achieve greater subjective amplitude, you can use the dynamic amplification. Dynamic amplification automatically changes the border of the lower frequency filter alignment in the direction of the ultrasonic transducer and the cutoff frequency of the filter 403 low frequencies used in the loudspeaker of the audio frequencies, based on the current requirements for SPL. Thus, based on the input sound signal -3 dB point of both filters is automatically regulated, so achieving the desired SPL. In the most basic implementation of the boundary of the lower frequency directional ultrasonic transducer and frequency -3 dB filter 403 low frequency for a loudspeaker of the audio frequencies are the same and may be called the crossover frequency.

For example, to the GDS signal, want to play, has a small amplitude, frequency separation may be chosen as low as possible, see figa. This choice maximizes audio tag from the point of reflection of the directed ultrasonic transducer, providing a strong auditory illusion. If the amplitude of the signal that you want to play, exceeds the maximum possible SPL directional ultrasonic transducer at a given frequency separation, the crossover frequency can be increased to take advantage of the increased efficiency of the directed ultrasonic transducer at high frequencies, see figv. This choice enables output with higher SPL and lower distortion, but slightly reduces the strength of the auditory illusion. Dynamic amplification respectively sacrifices power audio illusions in exchange for maximum SPL system.

It should be noted that "ultrasonic speaker and a regular speaker"used in the legend on figa and figv are directed ultrasonic transducer and loudspeaker range of sound frequencies, respectively. The same is true for Figo and figv.

The relationship that defines the instantaneous frequency separation and SPL system, you can create dependenciesin the formula Berktay. If- max the maximum undistorted SPL sound (PA), which the ultrasonic speaker can be achieved at 1000 Hz, and- required instant SPL (PA), the split pointis

.

In the above-described embodiment, when increasing the crossover frequency decreases the relative strength of the directed sound label, released from directional ultrasonic transducer, while the unwanted label aimed at speaker audio frequency increase. The result is a weaker sound illusion. To maximize performance, the boundary of the lower frequency of the filter alignment in the direction of the ultrasonic transducer and the boundary frequency of the low pass filter for speaker audio frequency can be controlled independently on the basis of psychoacoustic optimized system. This is a surround sound system would limit the energy transferred by low-frequency loudspeaker, above the critical frequency range, for example from 800 Hz to 2000 Hz. Thus, the relative strength of the directed sound label, released directional ultrasonic transducer is maintained above this critical frequency band due to the flat frequency characteristics, see figa and figv. Now the convenient dynamic gain can donate a maximum amplitude in exchange for a flat frequency response, and slightly affected the strength of auditory illusions. The exact nature of the dynamic gain is then determined by the function psychoacoustic weighting optimized to maximize the power of illusion at all levels of the sound output.

The choice of dynamic amplification may depend on the application. For example, for applications Hi-Fi flat frequency response can be considered as the most important factor, and could apply the basic layout of dynamic amplification. For home theater applications the most important factor can be considered as the achievement of strong labels localization from the rear. In this case, the psychoacoustic optimized dynamic amplification would be most appropriate.

Fig.9 shows an exemplary architecture of a surround-sound system with dynamic amplification in accordance with the invention. This architecture is the architecture of figure 2, which additionally contains the 900 block management dynamic amplification. The mentioned unit 900 controls the crossover frequency based on the maximum SPL, as discussed above. The crossover frequency is transmitted to the first circuit 303 and the second control circuit 307 controls.

You will need to take into account that the above description for clarity has described embodiments of the invention with reference to different functional the global schema, blocks and processors. However, it will become evident that it can be used any suitable distribution of functionality between different functional circuits, blocks or processors without downplaying the invention. For example, functionality illustrated to be performed by separate processors or controllers may be performed by a single processor or controller. Therefore, references to specific functional blocks or diagrams should be considered only as references to suitable means for providing the described functionality, and does not indicate a strict logical or physical structure or organization.

The invention can be implemented in any suitable form including hardware, software, firmware, or any combination. The invention can be implemented, at least partially, in the form of computer software running on one or more data processors and/or digital signal processors. The elements and components of a variant embodiment of the invention may be physically, functionally and logically implemented in any suitable way. In fact, the functionality can be implemented in one block, in mnozhestvennom or as part of other functional blocks. Essentially, the invention can be implemented in a single unit, or may be physically and functionally distributed between different units, circuits and processors.

Although the present invention is described with reference to certain versions of the implementation, it does not mean limited to a particular form set forth in this document. On the contrary, the present invention is limited only by the attached claims. Moreover, although the sign may appear to be described in relation to specific variants of implementation, the specialist in the art will understand that various aspects of the described embodiments may be combined in accordance with the invention. In the claims the term "comprising" does not exclude other elements or steps.

In addition, although not listed separately, many tools, elements, circuits or stages of the method may be implemented, for example, a single scheme, unit or processor. Moreover, although individual features may be included in different claims, they can advantageously be combined, and the inclusion in different claims does not imply that the combination of features is not feasible and/or advantageous. The inclusion of the feature in one category of claims is not podrazumeva the t limit this category, but rather specifies that, when necessary, the grounds equally applicable to other categories of claims. In addition, the order of signs in the claims do not imply any specific order that must be processed signs, and in particular, the order of individual steps in the claim on the way does not imply that the steps must be performed in this order. Rather, the stages can be performed in any suitable order. Moreover, a single link does not exclude many. Thus, the reference to "first", "second" etc. does not exclude many. The reference position in the formula of the invention are given only as an illustrative example and should not be construed as limiting the scope of the claims in any way.

1. Bose surround sound system, containing:
scheme (301) for receiving multi-channel surround signal containing at least one channel environment;
directional ultrasonic transducer (305) for the emission of ultrasound in the direction of the surface to achieve the listening position (111) by reflection from said surface;
the first scheme (303) control for the formation of the first control signal for the directional ultrasonic transducer (305) of the surround channel signal environment;
loud is oritel (309) range of audio frequencies;
the second scheme (307) management for forming a second control signal for a loudspeaker (309) audio band of the surround signal; and
scheme (401) delay to make the delay of the second component signal, the second control signal arising from the volume of the signal relative to the first component signal in the first control signal arising from the volumetric alarm;
moreover, the delay exceeds the delay difference in the transmission path between the transmission path from the directional ultrasonic transducer (305) to the position of the (111) listen to and a direct path from the loudspeaker (309) range of sound frequencies to the position of the (111) listen to not less than 1 MS and not more than 40 MS.

2. The surround sound system according to claim 1, in which diagram (401) delay configured to change the delay in response to the delay in the transmission path, and the delay in the transmission path specifies the delay of the transmission path from the directional ultrasonic transducer (305) to the position of the (111) listen.

3. The surround sound system according to claim 1, in which diagram (401) delay configured to change the delay in response to the value of the position of the sound source.

4. The surround sound system according to claim 1, in which the first frequency band band proponenets the formation of the first control signal from the surround signal differs from the second frequency range bandwidth for the formation of the second control signal of the surround signal.

5. The surround sound system according to claim 4, in which the upper cutoff frequency for the first frequency range bandwidth above the upper cutoff frequency to the second frequency range bandwidth.

6. The surround sound system according to claim 1, in which the second circuit (307) contains a control filter (403) low frequencies.

7. The surround sound system according to claim 1, in which the second circuit (307) control is additionally executed with the possibility of forming a second control signal of the front channel multi-channel surround signal.

8. The surround sound system according to claim 1, additionally containing a scheme for changing the axial direction of the directional ultrasonic transducer (305) relative to the axial direction of the loudspeaker (309) audio frequency.

9. The surround sound system according to claim 1, additionally containing a circuit for receiving the measurement signal from the microphone; and a scheme for adapting the level of the second component signal, the second control signal arising from the volume of the signal relative to the first component signal in the first control signal arising from the surround signal, in response to the measuring signal.

10. The surround sound system according to claim 1, in which the normalized ratio of the compensated delay between the second component of the signal in the second control is next signal, emerging from the surround signal, and the first component of the sound signal in the first control signal arising from the volume signal is not less than 0,50.

11. The surround sound system according to claim 1, additionally containing a circuit for receiving the measurement signal from the microphone; and a scheme for adapting the axial direction of the directional ultrasonic transducer (305) in response to the measuring signal.

12. The way to a surround-sound system that contains a directional ultrasonic transducer (305) for the emission of ultrasound in the direction of the surface to achieve the provisions of the (111) listen by reflection from said surface, and the method comprises the steps are:
accept multi-channel surround signal containing at least one channel environment; and
generate a first control signal for the directional ultrasonic transducer (305) of the surround channel signal environment;
form the second control signal to the loudspeaker (309) audio band of the surround signal;
make the delay of the second component signal, the second control signal arising from the volume of the signal relative to the first component signal in the first control signal arising from the volumetric alarm;
moreover, the latency exceeds the difference between the backside of the LCD in the transmission path between the transmission path from the directional ultrasonic transducer (305) to the position of the (111) listen to and a direct path from the loudspeaker (309) range of sound frequencies to the position (111) listen to not less than 1 MS and not more than 40 MS.



 

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FIELD: physics, acoustics.

SUBSTANCE: invention relates to processing audio signals, particularly to improving intelligibility of dialogue and oral speech, for example, in surround entertainment ambient sound. A multichannel audio signal is processed to form a first characteristic and a second characteristic. The first channel is processed to generate a speech probability value. The first characteristic corresponds to a first measured indicator which depends on the signal level in the first channel of the multichannel audio signal containing speech and non-speech audio. The second characteristic corresponds to a second measured indicator which depends on the signal level in the second channel of the multichannel audio signal primarily containing non-speech audio. Further, the first and second characteristics of the multichannel audio signal are compared to generate an attenuation coefficient, wherein the difference between the first measured indicator and the second measured indicator is determined, and the attenuation coefficient is calculated based on the obtained difference and a threshold value. The attenuation coefficient is then adjusted in accordance with the speech probability value and the second channel is attenuated using the adjusted attenuation coefficient.

EFFECT: improved speech perceptibility.

12 cl, 5 dwg

Slit type gas laser // 2273116

FIELD: quantum electronics, possible use for engineering technological slit type gas lasers.

SUBSTANCE: slit type gas laser has hermetic chamber, a pair of metallic electrodes, alternating voltage source, a pair of dielectric barriers, and an optical resonator. Chamber is filled with active gas substance. Metallic electrodes are mounted within aforementioned chamber, each of them has surface, directed to face surface of another electrode. Source of alternating voltage is connected to aforementioned electrodes for feeding excitation voltage to them. Dielectric barriers are positioned between metallic electrodes, so that surfaces of these barriers directed to each other form slit discharge gap for forming of barrier discharge in gas substance.

EFFECT: possible construction of slit type gas laser, excited by barrier discharge, dielectric barriers being made specifically to improve heat drain from active substance of laser, decrease voltage fall on these dielectric barriers, provide possible increase of electrodes area, improve efficiency of laser radiation generation, increase output power of laser, improve mode composition of its output signal.

8 cl, 4 dwg

FIELD: stereophonic systems with more than two channels.

SUBSTANCE: in accordance to the method, data is generated for parametric codes of first subset of sound input channels for first frequency area by using parametric multi-channel encoding; and parameter code data is generated for second subset of sound input channels for second frequency area by means of application of parametric multi-channel audio-encoding, where the second frequency area is different from the first frequency area; and the second subset of sound input channels is different from the first subset of sound input channels.

EFFECT: reduced data processing load in encoder and decoder, and also reduced BCC bit code streams.

6 cl, 2 dwg

Audio coding // 2325046

FIELD: audio coding.

SUBSTANCE: with the binaural coding, only one monophonic channel is coded. An additional layer contains parameters for the LH and RH signals. A coder is described, which associates transient process information extracted from the monophonic coded signal with parametric multichannel layers. Transient process locations may also be determined directly from the bit flow or calculated using other coded parameters (e.g., the window switch flag if specified in customer's requirements).

EFFECT: increase in efficiency due to use of transient process information in parametric multichannel layer.

13 cl, 4 dwg

FIELD: physics.

SUBSTANCE: said utility invention relates to sound recording and sound reproduction equipment and may be used for recording and restoration of a multi-dimensional acoustic scene, as well as during its transmission through media. In a recording room, the acoustic axes of all microphones are directed towards the centre of the acoustic scene being recorded, which is located on a vertical plane passing through the performers' front, the acoustic scene centre is located at the listeners' head level and in the middle of the microphones; in the listening room, the acoustic system arrangement on the vertical plane relative to the centre of the acoustic scene being restored is equivalent to the arrangement of microphones in the recording room; during transmission of all acoustic scene signal components from the microphone to the acoustic system and their amplification, output amplitude and phase relationships equivalent to the input ones are provided; displacement of acoustic systems in the vertical plane performs their phasing between one another, and rotation of the acoustic systems converges their axes into the point of acoustic scene restoration. When multi-band acoustic systems are used, the band phase adjustment and acoustic axis angles convergence may be performed online.

EFFECT: possibility to restore amplitude/phase acoustic scene.

2 cl, 2 dwg

FIELD: radio engineering.

SUBSTANCE: invention relates to device and method of multichannel sound signal processing in the compatible stereo format. While processing the multichannel sound signal having at least three initial channels, (12) the first mixing channel and the second mixing channel which are extracted from the initial channels are transmitted. (14) Additional channel information is calculated for the initial channel selected from initial channels in such a way so that mixing channel or combined mixing channel, including the first and the second mixing channels, generate approximation of the selected initial channel using weighting with additional channel information. Additional channel information and the first/second mixing channels form output data (20), which are to be transmitted to the decoder. If a low-level decoder is used, only the first/second mixing channels are decoded; if a high-level decoder is used, a composite multichannel sound signal is transmitted basing on mixing channels and additional channel information.

EFFECT: due to additional channel information occupies few bits and decoder does not use an inverse matrix, effective and high-quality multichannel extension for stereo record-players and multichannel record-players is obtained.

29 cl, 10 dwg

FIELD: physics, acoustics.

SUBSTANCE: invention refers to multichannel audio signal processing, specifically to multichannel audio signal restoration using primary channel and parametrical supplementary information. Multichannel synthesiser contains postprocessor for postprocess characterisation of restoration or values derived from restoration parameter for current time line of input signal so that postprocessed parameter of restoration or postprocessed value differs from relative quantised and inversely quantised parameter by that value is postprocessed parameter of restoration or derives value are not limited by quantisation step length. Multichannel restoration unit (12) applies postprocessed parameter of restoration to restore multichannel output signal. Technical result consists that by postprocessing of restoration parameters with reference to multichannel coding/decoding enables low data transfer rate, on the one hand, and high quality, on the other hand, as far as strong changes in restored multichannel output signal is lowered owing to great quantisation step length for restoration parameter, being preferable due to required data transfer rate.

EFFECT: improved quality of signal transmission.

25 cl, 16 dwg

Audio encoding // 2363116

FIELD: communication devices.

SUBSTANCE: invention relates to encoding a multichannel audio signal, particularly encoding a multichannel signal containing first, second and third signal components. The method of encoding a multichannel audio signal containing at least, a first signal component (LF), second signal component (LR) and a third signal component (RF), involves encoding the first and second signal components using a first parametric encoder (202) to obtain the first encoded signal (L) and the first set (P2) of coding parametres. The first encoded signal and an additional signal (R) are encoded using a second parametric encoder to obtain a second encoded signal (T) and a second set (P1) of coding parametres. The additional signal is obtained from at least the third signal component, and is a multichannel audio signal in form of at least, the resultant encoded signal (T), obtained from at least, the second encoded signal, first set of coding parametres and second set of coding parametres.

EFFECT: more efficient encoding.

13 cl, 13 dwg

FIELD: individual supplies.

SUBSTANCE: invention concerns multichannel sound reproduction systems, particularly application of psychoacoustic principles in acoustic system design. Surrounding sound reproduction system uses a number of filters and system of main and auxiliary speakers producing effect of phantom rear channels of surrounding sound or phantom surrounding sound by acoustic system or system of two speakers installed in front of listener. Acoustic system includes left and right input signals of surrounding sound and left and right frontal input signals. Left and right auxiliary speakers and left and right main speakers are positioned in front of audition position. Distance between respective main and auxiliary speakers is equal to distance between ears of an average human.

EFFECT: surrounding sound reproduction by speakers installed only in front of listener.

59 cl, 21 dwg

FIELD: physics; acoustics.

SUBSTANCE: invention relates to coding several signals from audio sources, which must be transmitted or stored with the objective of mixing in order to synthesise a wave field, signals for multichannel three-dimensional or stereophonic audio after decoding signals from the sources. The proposed method provides for efficient composite coding signals compared to their separate coding, even when there is no redundancy between the signals. This is possible due to statistical properties of signals, properties of the coding method and spatial hearing. The sum of the signals is transmitted together with the statistical properties, which mainly determine spatial features for final mixed audio signals which are important for perception. The signals are reconstructed in a receiver so that statistical properties are approximately identical to corresponding properties of initial signals from the sources.

EFFECT: more efficient coding when mixing coded signals.

22 cl, 14 dwg

FIELD: physics; communications.

SUBSTANCE: invention relates to technology of multichannel audio and, specifically, to applications of multichannel audio in connections with headphone technologies. The device for generating an encoded stereo signal from a multichannel presentation includes a multichannel decoder (11), which forms three or more channels from at least one main channel and parametric information. Said three or more channels are subject to processing (12) headphone signals so as to generate an uncoded first stereo channel and an uncoded second stereo channel, which are then input into a stereo encoder (13) so as to generate an encoded stereo file at the output side. The encoded stereo file can be transmitted to any suitable playback device in form of a CD player or portable playback device such that, the user not only receives a normal stereo impression, but a multichannel impression as well.

EFFECT: efficient signal processing concept, which allows for multichannel quality playback on headphones in simple playback devices.

12 cl, 11 dwg

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