WO2011161567A1 - Système et procédé de reproduction de son et pilote associé - Google Patents

Système et procédé de reproduction de son et pilote associé Download PDF

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Publication number
WO2011161567A1
WO2011161567A1 PCT/IB2011/052374 IB2011052374W WO2011161567A1 WO 2011161567 A1 WO2011161567 A1 WO 2011161567A1 IB 2011052374 W IB2011052374 W IB 2011052374W WO 2011161567 A1 WO2011161567 A1 WO 2011161567A1
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Prior art keywords
driver
signal
processing path
drive
signal processing
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PCT/IB2011/052374
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English (en)
Inventor
Werner Paulus Josephus De Bruijn
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Koninklijke Philips Electronics N.V.
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Publication of WO2011161567A1 publication Critical patent/WO2011161567A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/12—Circuits for transducers, loudspeakers or microphones for distributing signals to two or more loudspeakers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
    • H04R2201/40—Details of arrangements for obtaining desired directional characteristic by combining a number of identical transducers covered by H04R1/40 but not provided for in any of its subgroups
    • H04R2201/403—Linear arrays of transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2203/00—Details of circuits for transducers, loudspeakers or microphones covered by H04R3/00 but not provided for in any of its subgroups
    • H04R2203/12—Beamforming aspects for stereophonic sound reproduction with loudspeaker arrays
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R5/00—Stereophonic arrangements
    • H04R5/02—Spatial or constructional arrangements of loudspeakers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S3/00—Systems employing more than two channels, e.g. quadraphonic
    • H04S3/008—Systems employing more than two channels, e.g. quadraphonic in which the audio signals are in digital form, i.e. employing more than two discrete digital channels

Definitions

  • the invention relates to sound reproduction using a speaker array and in particular, but not exclusively to sound reproduction for a surround sound system.
  • a single speaker box system has been developed wherein the left front and surround channels are reproduced by a dipole configuration of two loudspeakers. Similarly, the right front and surround channels are reproduced by a dipole configuration of two other loudspeakers.
  • the notch (or specifically the null) direction of the dipole is steered electronically (by delaying the signal to one of the two dipole speakers) towards the position of the listener. This results in the listener not receiving any (or at least very little) sound for the spatial channel directly from the loudspeakers, so that the sound that reaches him consists mainly of sound reflected from the walls. This has proven to give a very wide, spacious, and enveloping sound sensation. Thus, an improved sound sensation is achieved with very low complexity.
  • the approach may for example also be used in compact stereo systems or surround sound systems based on two separate loudspeaker units, e.g. one for the left front- and surround channels and one for the right front- and surround channels.
  • the technique is able to create a desirable wide, enveloping, and diffuse sound sensation, it also has some associated drawbacks.
  • the front channels may be perceived as spatially less well defined, and the sound stage and individual localized sounds sources may be perceived slightly non-focussed and "blurry". This may in some cases degrade the spatial experience.
  • conflicting requirements exist that a directed sound radiation may seek to address.
  • conflicting requirements often lead to suboptimum trade-offs.
  • it is at the same time desirable to have low complexity and thus a system providing an improved trade-off between such requirements would be advantageous.
  • a sound reproduction system allowing increased flexibility, reduced complexity, an improved spatial experience, reduced cost, reduced computational requirements, improved spatial definition, increased sound stage width, facilitated implementation and/or improved performance would be advantageous.
  • the Invention seeks to preferably mitigate, alleviate or eliminate one or more of the above mentioned disadvantages singly or in any combination.
  • a sound reproduction system comprising: a speaker array comprising at least a first driver, a second driver and a third driver; a receiver for receiving an input signal; and a drive circuit for generating from the input signal a first drive signal for the first driver, a second drive signal for the second driver, and a third drive signal for the third driver; wherein the drive circuit is arranged to generate the first drive signal and the third drive signal to drive the first driver and the third driver in a dipole configuration; and to direct a notch of the sound radiation pattern of the speaker array in a first direction by generating the second drive signal with at least a first offset relative to the first drive signal, the first offset comprising at least one offset selected from the group of a phase offset and a gain offset.
  • the invention may provide an improved sound reproduction system in many scenarios.
  • an improved trade-off between different requirements may be achieved and in many embodiments an advantageous combination of a wide sound stage with well defined sound sources can be achieved.
  • the system may have low complexity and in particular complex beam steering can be avoided.
  • the approach may in many cases for example allow the direction of the notch to be controlled simply by adjusting a (possibly frequency dependent) gain difference for the driving of the second speaker relative to the first and third speaker.
  • a three-loudspeaker configuration may be used to create a directional response where two drivers are used as an unsteered dipole pair with the third driver being used to cancel the sound field of the dipole pair in a selected direction.
  • the cancellation angle can in many scenarios be controlled simply by changing the (possibly frequency-dependent) gain balance between the dipole pair and the second driver.
  • the approach may for example allow an advantageous rendering of spatial side and/or surround channels in a surround sound system using a single speaker array located in front of the listener.
  • an improved spatial definition may be achieved while maintaining a wide sound image and low complexity.
  • an improved spatial definition may be achieved without significant complexity increase.
  • a clearer and spatially more defined sound image can be achieved while maintaining a wide sound stage.
  • the approach may allow improved power efficiency at low frequencies and/or may provide improved robustness to small variations in system
  • the approach may allow facilitated and/or improved control of the direction of the notch and may in particular allow facilitated dynamic adaptation and variations of the notch direction.
  • the dipole configuration may result in a far field dipole radiation pattern.
  • the dipole configuration may specifically be achieved by the first and third drive signal being substantially identical while having a phase difference of 180°, i.e. the same signal may be fed to the first and third driver but with opposite phases.
  • the notch may specifically be a null.
  • the first offset may specifically be a gain offset and e.g. combined with a phase offset in the frequency domain.
  • the first offset may specifically comprise a gain offset combined with a substantially 90° phase offset (often in the interval of [80°; 100°] or even [85°;95°]).
  • the first direction may be different than a direction of the null (or notch) of the dipole configuration of the first and third drivers.
  • the drive circuit may specifically be arranged to modify a direction of a notch of the sound radiation pattern of the speaker array for the input signal from a direction of a dipole notch for the dipole by generating the second drive signal with the first offset (selected from the group of a phase offset and a gain offset) relative to the first drive signal.
  • the first offset is frequency dependent.
  • This may provide improved performance in many embodiments and may in particular compensate for frequency dependent variations in the in-air combinations of sound pressure levels from the individual drivers.
  • the first offset may be a frequency dependent gain combined with a frequency independent phase offset, e.g. in the interval of [80°; 100°] or even [85°;95°].
  • the frequency dependent gain may be substantially proportional to:
  • ⁇ /2 is the inter-driver distance
  • c is the speed of sound
  • ⁇ is the desired notch direction
  • ⁇ is the frequency
  • the drive circuit is arranged to provide a frequency dependent transfer function for generating the first drive signal from the input signal.
  • the drive circuit may similarly be arranged to provide a frequency dependent transfer function for generating the third drive signal from the input signal.
  • the frequency response for the first and third drivers may be the same.
  • This may allow an improved audio quality and may in particular allow compensation for frequency variations and equalization resulting from the interaction between the different drivers of the array.
  • the frequency response of the transfer function may provide a compensation for a frequency variation resulting from a frequency variation of the first offset as well as a frequency dependent in-air combining of sound pressure levels from the first driver, the second driver and the third driver in a first direction.
  • the generation of the first and/or third drive signals may include a filtering contribution substantially according to:
  • ⁇ /2 is the inter-driver distance
  • c is the speed of sound
  • ⁇ is the desired notch direction
  • ⁇ 3 ⁇ 4 is a desired angle of the frequency compensation
  • ⁇ is the frequency.
  • a phase difference between a transfer function for generating the first drive signal from the input signal and a transfer function for generating the second drive signal from the input signal is in the interval of 80° to 100° in a frequency interval of 100 to 2 kHz.
  • a phase difference of the transfer function for generating the first drive signal from the input signal and the transfer function for generating the second drive signal may be in the interval of 85° to 95° in a frequency interval of 100 Hz to 2 kHz.
  • the drive signal for the second driver may be phase offset by substantially 90° relative to the drive signals for the first and/or third drivers.
  • the phase offset may specifically be substantially constant over the operating frequency range.
  • the gain difference between a transfer function for generating the first drive signal from the input signal and a transfer function for generating the second drive signal from the input signal may be frequency dependent.
  • the transfer function for the second driver may have a varying (in the frequency domain) gain offset and constant phase offset relative to the first and/or third driver.
  • the drive circuit comprises a first signal processing path for generating the first drive signal, a second signal processing path for generating the second drive signal, and a third signal processing path for generating the third drive signal; and the first offset may be generated by the second signal processing path having a different frequency response than the first signal processing path and the third signal processing path.
  • the first signal processing path and the third signal processing path have substantially identical gain frequency responses.
  • the gain responses may differ by no more than 2dB for a frequency range from 500Hz to 2 kHz.
  • the second signal processing path may have a different gain and may e.g. deviate by more than 6 dB for at least some frequencies.
  • the first signal processing path, the second signal processing path and the third signal processing path comprise a shared signal processing path segment and separate signal processing path segments for each of the first signal processing path, the second signal processing path and the third signal processing path; and the shared signal processing path segment comprises a filter having a frequency dependent gain and a frequency dependent gain of a separate signal processing path segment for the first signal processing path is different from frequency dependent gain of a separate signal processing path segment for the second signal processing path.
  • This may provide a particularly advantageous implementation and may reduce complexity while maintaining high performance.
  • the first signal processing path and the third signal processing path comprise a common filter having a frequency gain variation and a gain of the second signal processing path is substantially frequency independent.
  • the gain of the second signal processing path may vary by no more than 2dB in a frequency range from 500Hz to 2 kHz.
  • the common filter may specifically be a first order low pass filter having a slope of around 6 dB per octave.
  • the common filter is independent of the first direction; and the sound system further comprises means for modifying the first direction by modifying a frequency independent gain offset of the second signal processing path relative to the first signal processing path.
  • This may provide a particularly advantageous implementation and may reduce complexity while maintaining high performance. In particular it may allow a low complexity and/or a robust approach for controlling the direction of the notch.
  • the approach may for example allow a particularly advantageous approach for (possibly dynamically) adapting the operation of the system to the specific characteristics and requirements of the particular audio environment.
  • the sound reproduction system further comprises: a circuit for dividing a received signal into an ambient sound signal and a non-ambient sound signal, and for generating the input signal to comprise the non-ambient sound signal but not the ambient sound signal.
  • the sound reproduction system further comprises: a circuit for introducing a time offset for the second drive signal relative to at least one of the first drive signal and the third drive signal, the time offset corresponding to a geometric characteristic of relative positions of at least two drivers of the speaker array.
  • the sound system is arranged to render at least one spatial channel, which specifically may be a front side channel.
  • the invention may provide a particular advantageous rendering of a spatial channel in a surround sound system.
  • the approach may in particular be arranged to provide particularly advantageous performance for a side or surround channel with an improved trade-off between the conflicting requirements for such sound reproduction.
  • a driver for a loudspeaker arrangement comprising a speaker array with at least a first driver, a second driver and a third driver; the driver comprising: a receiver for receiving an input signal; and a drive circuit for generating from the input signal a first drive signal for the first driver, a second drive signal for the second driver, and a third drive signal for the third driver; wherein the drive circuit is arranged to generate the first drive signal and the third drive signal to drive the first driver and the third driver in a dipole configuration; and to direct a notch of the sound radiation pattern of the speaker array in a first direction by generating the second drive signal with at least a first offset relative to the first drive signal, the first offset comprising at least one offset selected from the group of a phase offset and a gain offset.
  • a method of operation for a driver for a loudspeaker arrangement comprising a speaker array with at least a first driver, a second driver and a third driver; the method comprising: receiving an input signal; and generating from the input signal a first drive signal for the first driver, a second drive signal for the second driver, and a third drive signal for the third driver; wherein the generating comprises generating the first drive signal and the third drive signal to drive the first driver and the third driver in a dipole configuration; and directing a notch of the sound radiation pattern of the speaker array in a first direction by generating the second drive signal with at least a first offset relative to the first drive signal, the first offset comprising at least one offset selected from the group of a phase offset and a gain offset.
  • Fig. 1 illustrates an example of a speaker system for a surround sound system
  • Fig. 2 illustrates an example of elements of a sound reproduction system in accordance with some embodiments of the invention
  • Fig. 3 illustrates an example of a radiation pattern for a dipole configuration
  • Fig. 4 illustrates an example of a speaker coupling for a dipole configuration
  • Figs. 5 and 6 illustrate examples of elements of a sound reproduction system in accordance with some embodiments of the invention
  • Fig. 7 illustrates an example of frequency responses for an equalization filter for a sound reproduction system in accordance with some embodiments of the invention.
  • Figs. 8 to 13 illustrate examples of elements of a sound reproduction system in accordance with some embodiments of the invention.
  • Fig. 1 illustrates an example of a speaker system for a surround sound system in accordance with some embodiments of the invention.
  • the speaker system is a single speaker box 101 that comprises two speaker arrays 103, 105.
  • the speaker box 101 comprises a first speaker array 103 which is used to reproduce the left side front and surround channels and a second speaker array 105 which is used to reproduce the right side front and surround channels.
  • both speaker arrays 103, 105 are used to reproduce the centre signal.
  • the left speaker array 103 comprises a first driver 107, a second driver 109 and a third driver 111 which are controlled to provide a directional sound radiation.
  • the drivers may for example be loudspeaker units or other sound transducers.
  • the left front channel is rendered by radiating the sound in a direction which is not directly towards the assumed listening position 113. Rather, the sound is predominantly directed in a sideways direction 115 that allows the sound to reach the listening position 113 indirectly, such as e.g. via reflections of walls.
  • a notch is formed in the direction 117 towards the listening position to reduce the direct sound radiation to the listener.
  • This approach has been found to provide an enhanced audio perception and may in particular provide a perception of more enveloping and wide stereo signal.
  • the spatial perception of the left front signal may be perceived to originate from the side rather than from the single speaker box 101.
  • the inventor has realized if such an approach is based on a low complexity two speaker dipole configuration, it tends to result in a suboptimal user experience in some situations.
  • the perception of a potential blurred front image may be caused by such a low complexity approach resulting in sound being radiated in different and possibly undesired directions.
  • a dipole radiation pattern has two lobes in opposite directions and this results in sound sources that are supposed to be localizable and well-defined (and which are usually mainly positioned in the front channels) possibly becoming somewhat diffuse or blurry in some cases. This is because the sound of, for example, the left-front channel, may actually be radiated to both the left- and right side wall, leading to a "spatial cross-talk" (and indeed with an inverted phase).
  • the three driver speaker arrays are used to provide an improved spatial experience.
  • the approach may be used to enable a wide sound stage to be produced from a compact device in front of the listener yet with a spatially more defined, and typically less blurry, image.
  • an additional driver of the array is used to at least partly cancel the field of the dipole in a selected direction.
  • the additional driver is used to generate a notch which can be directed towards the listening position.
  • the notch direction can be modified by low complexity processing of the signal for the additional driver relative to the two other drivers. Indeed, in many scenarios, a simple gain variation may be used to modify the notch direction.
  • Fig. 2 illustrates a driving arrangement for the speaker array 105 of Fig. 1.
  • the driver arrangement drives three equally- spaced drivers 107, 109, 111 arranged in line (i.e. a three-speaker line array).
  • the arrangement of Fig. 2 comprises a receiver 201 which receives an input signal to be rendered by the system.
  • the input signal is the left front channel of a surround sound multi-channel signal.
  • the receiver 201 is coupled to a drive circuit 203 which is arranged to generate a drive signal for each of the three drivers 107, 109, 111.
  • the drive circuit comprises a first signal processing path 209 which generates a first drive signal for the first driver 107, a second signal processing path 211 which generates a second drive signal for the second driver 109, and a third signal processing path 213 which generates a third drive signal for the third driver.
  • Each of the signal processing paths 209, 211, 213 provides a transfer function for generating the respective drive signal from the input signal provided by the receiver 201. It will be appreciated that although the signal processing paths 209, 211, 213 in Fig. 2 are illustrated as separate and parallel signal processing paths, some processing may be shared or common for all paths. In particular, the signal paths 209, 211, 213 may comprise a shared/ common signal processing path segment as well as separate and individual signal processing path segments for each individual driver.
  • the drive circuit 203 is arranged to generate the drive signals for the first driver 107 and the third driver 111 of the speaker array 103 such that these are operated in a dipole configuration.
  • a first and third drive signal is generated from the input signal such that the two drivers 107, 111 behave as a single dipole in the far field, i.e. at a distance where the drivers 107, 111 are sufficiently close to be considered a single point sound source.
  • the dipole configuration is furthermore achieved by the drivers 107, 111 being sufficiently close for rendering the relevant frequencies as a dipole sound source.
  • a distance between the centers of the drivers 107, 111 of no more than 50 cm, or in many embodiments advantageously no more than 25 cm, is sufficient to ensure that the two drivers 107, 111 can be operated in a dipole configuration for distances to the listening position of, say, more than lm.
  • An example of a dipole radiation pattern is illustrated in Fig. 3.
  • the two drivers 107, 111 operated in a dipole configuration are the outside drivers.
  • the dipole configuration may specifically be achieved by the first and third drive signal being substantially identical but being phase inverted, i.e. by being substantially 180° out of phase relative to each other. This may for example simply be achieved by feeding the same signal to both drivers with the wires for the driver being reversed for one of the drivers relative to the other as illustrated in Fig. 4.
  • the third signal processing path 213 may comprise an inverter not included in the first signal processing path 209 (or vice versa).
  • the first and third drive signal for the first and third driver 107, 111 respectively may be the same signal except that one of the signals is phase inverted.
  • the drive circuit 203 generates a second drive signal for the second driver 109.
  • the second driver 109 is located between the two drivers 107, 111 operating as a dipole. Due to the symmetry of the configuration, the resulting configuration can be seen as a coincident dipole-monopole pair with the first and third driver 107, 111 providing the dipole and the second driver 109 providing the monopole.
  • the second drive signal is generated from the input signal but with at least one of a phase offset and a gain offset relative to the first drive signal.
  • the generation of the second drive signal for the second driver 109 may include a phase offset and/or a gain offset that is not included in the generation of the first drive signal (or the third drive signal).
  • the second signal processing path 211 comprises a phase shift and/or gain modification function that is not included in the first and third signal processing paths 209, 213.
  • the second driver 109 is in this way used to modify the radiation pattern of the speaker array 103 from being that of a dipole.
  • the relative offset applied when generating the second drive signal allows the pattern to be modified such that a notch is steered in a desired direction, and this is in the system used to direct this notch in the direction of the listening position.
  • a notch (or specifically a null) may be generated in a different direction than the notch (or null) of the dipole configuration. This notch may result in the direct path from the speaker array 103 to the listening position 113 being attenuated such that the sound is predominantly perceived from indirect paths.
  • the second driver 109 is used to control the radiation pattern such that a notch is provided in the desired direction while at the same time achieving a more desirable radiation pattern.
  • this modified approach can be achieved with a very low complexity as it merely requires the offsetting of one signal relative to the other.
  • a much simpler approach than a conventional beam steering approach can be achieved.
  • the resulting sound pressure level from the three drivers can be determined. It is assumed that all three drivers can be considered to be monopoles.
  • the second driver 109 may then generate a notch, and specifically a null, in a desired direction ⁇ by modifying this radiation pattern.
  • This equation thus provides a modification of the second drive signal relative to the first drive signal in order to provide a cancellation in the desired direction.
  • Fig. 5 illustrates an example of a drive circuit in accordance with such an approach.
  • the input signal s(t) is fed to an equalization filter 501 which is part of a common path segment for the signal processing paths 209, 21 1, 213 for generating the drive signals from the input signal.
  • this filter will be assumed to simply pass the input signal s(t) through to the three separate signaling processing path segments for generating the three different drive signals (i.e. the system will be considered without the equalization filter 501).
  • the first drive signal is generated as identical to the (equalized) input signal and the third drive signal is generated as the inversed (equalized) input signal.
  • the first and third drivers 107, 111 are coupled in a dipole configuration and generate a sound field having a radiation pattern as indicated in Fig. 4.
  • the signal processing path for the second driver 109 comprises a filter 503 and a 90° phase shifter 505. This reflects equation 2 which essentially comprises a 90-degree phase shift operation and a frequency dependent gain offset.
  • the transfer response of the signal processing path generating the second drive signal has a frequency- independent phase offset of 90° relative to the transfer response for generating the first drive signal (and consequently of - 90° relative to the transfer response for generating the third drive signal).
  • the phase of the second drive signal is halfway between the phases of the first and third drive signals.
  • the 90° phase shifter 505 may e.g. be implemented as a Hilbert-transform which will be well known to the skilled person. Such a transform may e.g. be implemented by means of a filter. In a digital system, this is typically implemented as an FIR filter. The required length of the FIR filter is determined by the lowest frequency where the processing should still be effective.
  • phase difference between the transfer function for generating the first drive signal from the input signal and the transfer function for generating the second drive signal from the input signal is in the interval of [80°, 100°] or in some cases [85°,95°] for a frequency interval of 100 to 2 kHz.
  • equation 2 illustrates that a gain offset should be applied to the second signal processing path 211 relative to the first signal processing path 209.
  • this gain offset depends on the desired direction of the null, or in other words the direction of the null can simply be determined by controlling the gain offset between the different signal processing paths.
  • the gain offset is preferably frequency dependent and is therefore in the example of Fig. 5 implemented as a filter 503 rather than as a simple gain.
  • the filter has the transfer function H? which in the specific example is given by:
  • phase shift 505 and the filter 503 can be implemented in the same filter.
  • the total sound pressure in an arbitrary angle a generated by the system of Fig. 5 can thus be determined as the sum of the individual contributions, i.e. as:
  • equation 4 also indicates that a frequency dependent sound pressure level is generated, i.e. that the reproduced frequency response of the system as a whole is not flat but may introduce a coloration of the sound.
  • the frequency response is furthermore dependent on the angle a and thus on the position of the listener.
  • the drive circuit 203 is arranged to provide a frequency dependent transfer function for generating the first drive signal from the input signal.
  • the generation of the first signal from the input signal introduces a frequency shaping. The same approach may also be applied for the third drive signal.
  • the frequency response of the transfer function is specifically arranged such that it provides a compensation for the frequency variation/ shaping that result from a frequency variation of the offset of the second drive signal and the frequency dependent in- air combining of sound pressure levels from the first driver 107, the second driver 109 and the third driver 1 1 1 in a first direction.
  • the frequency shaping may be used to compensate for the frequency shaping that is introduced by the described approach.
  • this compensation is simply achieved by a frequency shaping of the input signal.
  • the equalization filter 501 is located in a shared or common segment of the signal processing paths 209, 21 1 , 213 such that the input signal is pre-compensated before being applied to the individual signal processing paths.
  • the shared signal processing path segment comprises an equalization filter 501 that has a frequency dependent gain. This frequency dependent gain is in this example thus common for all drivers 107, 109, 1 1 1 whereas the frequency dependent gain of the separate segments of the signal processing paths are different for the first and second driver 107, 109 (as well as for the second and third driver 109, 1 1 1) by virtue of filter 503.
  • a frequency varying gain filter in the form of the equalization filter 501 is introduced to pre- filter the input signal so as to compensate for the frequency shaping by the rest of the rendering system.
  • the equalization filter 501 may be given by:
  • the desired processing of the rendering system can be achieved precisely or approximately in many different ways.
  • a frequency dependent gain offset for the second driver 109 relative to the first driver 107 is provided.
  • the first and third signal processing paths 209, 213 may advantageously be arranged to have a common frequency gain variation whereas the frequency gain of the second signal processing path 211 is kept substantially constant, e.g. within 2dB in the frequency range from 200 Hz to 3 kHz.
  • the gain offset may be introduced by processing in the first and third signal processing paths 209, 213 rather than in the second signal processing path 211.
  • the same effect can be achieved by only applying the equalization filter of equation 5 to the signals fed to the outer two drivers speakers 107, 111.
  • the generation of the second drive signal need not include any frequency-dependent gain as the equalization filter and the frequency-dependent gain factor H cancel each other.
  • the notch direction may be dynamically modified (e.g. to track a user's position), to have fixed equalization filters that are independent of ⁇ for achieving a flat overall system response, and to have a frequency- independent gain for the second driver that only depends on ⁇ for controlling the notch angle.
  • H EQ and H 2 of Fig. 5 can be replaced by a fixed equalization filter in the path of the first and third drivers 107, 111 with a response that is substantially proportional to l/co (i.e. has -6 dB/octave frequency slope).
  • FIG. 8 An example of such a system is shown in Fig. 8.
  • the common filter of the first and third signal processing paths 209, 213 (but not of the second signal processing path 211) is thus independent of the direction of the notch whereas the frequency independent gain of the second signal processing path 211 is used to control the direction of the notch.
  • the common filter is specifically a first order low pass filter with a slope of 6 dB per octave.
  • An example of such a system is shown in Fig. 9.
  • the phase offset between the second driver 109 and the first and third drivers 107, 111 is introduced by a phase shift of the second signal processing path 211.
  • the phase offset may be introduced by a phase shift in the first signal processing path 209 or the third signal processing path 213.
  • Figs. 10- 13 illustrates examples of such implementations corresponding to the approaches of Figs. 5, 6, 8 and 9 respectively.
  • An advantage of several of these approaches is that the second signal processing path 211 does not need to actually include any processing (or only a simple gain such as in the system of Fig. 12). Furthermore, by combining the phase shift operation with the other filtering in the appropriate path, an even lower complexity can be achieved.
  • the drive circuit may further be arranged to introduce a time offset for the second drive signal relative to at least one of the first and third drive signal where the time offset is determined in response to a difference between a distance between the first driver 107 and the second driver 109 and a distance between the third driver 1 1 1 and the second driver 109.
  • the second driver 109 is not exactly at the center (i.e. at a distance of Ax/2 from both the first and third driver 107, 11 1), but is shifted a distance x 2 along the line connecting the drivers (x 2 is negative for a shift towards the first driver 107 and positive towards the third driver 1 1 1).
  • Equations 1 and 2 are still valid. However, since the position of the second driver 109 has shifted, a frequency- independent delay (At) 2 is added to the second drive signal in order to compensate for this. This delay may specifically have the value: ⁇ ⁇ ) 3 ⁇ 4 sina _ (8)
  • this time offset (delay or advance dependent on the direction of the displacement and the notch angle a) can e.g. be incorporated in the Hilbert transform filter for the second driver 109 in the system of Fig. 5 and thus an additional delay element is typically not required.
  • the described approach may in particular provide a wide soundstage while maintaining spatially well defined sound source positions.
  • the described approach is used selectively.
  • the described approach may be used to render the front side channels of a spatial surround sound signal whereas other rendering approaches are used for the surround channels.
  • the approach may be used to process channels that are intended to be perceived spatially wide yet clearly defined and localized, whereas channels that are advantageously perceived as diffuse and ambient sounds are processed by a rendering approach that provides a more diffuse experience, such as by a simple two driver dipole configuration.
  • the drive circuit comprises means for dividing the received signal into an ambient sound signal and a non-ambient signal.
  • This approach may for example be applied to a received stereo signal which can be divided into an ambient stereo signal and a non- ambient stereo signal where the ambient signal may tend to comprise background sounds whereas the non-ambient stereo signal may comprise one or more specific dominant sound sources.
  • the received signal is thus divided into signal components that meet an ambience criterion and signal components that do not meet the ambiance criterion.
  • the criterion may thus provide a suitable test for determining whether the signal components can be considered ambient and thus should be rendered more diffusely and less spatially well defined, or whether the signal components cannot be considered ambient and thus should be rendered spatially more well defined.
  • the input signal may be analyzed and separated into localized or spatially defined signal components, and diffuse or ambience components.
  • any suitable algorithm for separating a signal into such components may be used and that such algorithms will be known to the skilled person.
  • An example of suitable algorithms may e.g. be found in Harma, Aki; Faller, Christof, "Spatial Decomposition of Time- frequency Regions: Subbands or Sinusoids", AES Convention: 116 (May 2004) Paper Number :6061 ; R. IRWAN AND RONALD M. AARTS, "Two-to-Five Channel Sound Processing", J. Audio Eng. Soc, Vol. 50, No. 11, 2002 November or in US patent publication US20090092258 Al .
  • the two signal components are then rendered using different approaches.
  • the non-ambient signal components are rendered using the described approach whereas the ambient signal components are rendered using another approach, such as e.g. using a simple fixed dipole arrangement.
  • the power efficiency at low frequencies may be twice as high for the same inter-speaker distance as the total distance of the array is twice as high. This means less powerful amplifiers are needed for the same bass output, or higher bass output can be achieved with the same loudspeakers and power resulting in a more full sound. This also means that the cut-off of an additional subwoofer can be lowered, and its power requirements (and hence size) reduced.
  • notch angle is controlled by a simple adjustment of gain balance makes implementation of dynamic use cases in which the notch angle is changed dynamically, e.g. to track listener position, easier to implement (e.g. there is no need for delay interpolation).
  • the invention can be implemented in any suitable form including hardware, software, firmware or any combination of these.
  • the invention may optionally be
  • an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the invention may be implemented in a single unit or may be physically and functionally distributed between different units, circuits and processors.

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Circuit For Audible Band Transducer (AREA)

Abstract

L'invention porte sur un système de reproduction de son comprenant un ensemble de haut-parleurs (103) comportant au moins un premier pilote (107), un deuxième pilote (109) et un troisième pilote (111). Un récepteur (201) reçoit un signal d'entrée et un circuit de commande (203) génère des signaux de commande pour les trois pilotes (107, 109, 111) à partir de celui-ci. Le circuit de commande (203) est conçu pour générer le premier signal de commande et le troisième signal de commande pour commander le premier pilote (107) et le troisième pilote (111) dans une configuration de dipôle. En outre, il est conçu pour diriger une crevasse du motif de rayonnement sonore de l'ensemble de haut-parleurs (103) dans une première direction par génération du deuxième signal de commande avec un décalage de phase et/ou un décalage de gain. Dans de nombreux scénarios, un décalage de gain dépendant d'une fréquence simple et un décalage de phase indépendant d'une fréquence peuvent être utilisés. L'invention permet une expérience acoustique spatiale améliorée tout en maintenant une faible complexité.
PCT/IB2011/052374 2010-06-02 2011-05-30 Système et procédé de reproduction de son et pilote associé WO2011161567A1 (fr)

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EP10164683.4 2010-06-02

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3079375A1 (fr) 2015-04-10 2016-10-12 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Reproduction acoustique différentielle
WO2018023150A1 (fr) * 2016-08-01 2018-02-08 Blueprint Acoustics Pty Ltd Appareil de gestion de la distorsion dans un trajet de signal et procédé
US10306358B2 (en) 2015-04-27 2019-05-28 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Sound system
US10440492B2 (en) 2014-01-10 2019-10-08 Dolby Laboratories Licensing Corporation Calibration of virtual height speakers using programmable portable devices
WO2024054834A3 (fr) * 2022-09-07 2024-04-18 Sonos, Inc. Imagerie spatiale sur des dispositifs de lecture audio

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5870484A (en) * 1995-09-05 1999-02-09 Greenberger; Hal Loudspeaker array with signal dependent radiation pattern
US20070263888A1 (en) * 2006-05-12 2007-11-15 Melanson John L Method and system for surround sound beam-forming using vertically displaced drivers
US20090092258A1 (en) 2007-10-04 2009-04-09 Creative Technology Ltd Correlation-based method for ambience extraction from two-channel audio signals
WO2009112980A1 (fr) * 2008-03-14 2009-09-17 Koninklijke Philips Electronics N.V. Système sonore et procédé de fonctionnement associé

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5870484A (en) * 1995-09-05 1999-02-09 Greenberger; Hal Loudspeaker array with signal dependent radiation pattern
US20070263888A1 (en) * 2006-05-12 2007-11-15 Melanson John L Method and system for surround sound beam-forming using vertically displaced drivers
US20090092258A1 (en) 2007-10-04 2009-04-09 Creative Technology Ltd Correlation-based method for ambience extraction from two-channel audio signals
WO2009112980A1 (fr) * 2008-03-14 2009-09-17 Koninklijke Philips Electronics N.V. Système sonore et procédé de fonctionnement associé

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
HARMA, AKI, FALLER, CHRISTOF: "Spatial Decomposition of Time-frequency Regions: Subbands or Sinusoids", AES CONVENTION, vol. L 16, May 2004 (2004-05-01), pages 6061
R. TRAAN, RONALD M. PARTS: "Two-to-Five Channel Sound Processing", J. AUDIO ENG. SOC., vol. 50, no. 11, November 2002 (2002-11-01)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10440492B2 (en) 2014-01-10 2019-10-08 Dolby Laboratories Licensing Corporation Calibration of virtual height speakers using programmable portable devices
EP3079375A1 (fr) 2015-04-10 2016-10-12 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Reproduction acoustique différentielle
WO2016162445A1 (fr) 2015-04-10 2016-10-13 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Reproduction sonore différentielle
KR20170047333A (ko) * 2015-04-10 2017-05-04 프라운호퍼 게젤샤프트 쭈르 푀르데룽 데어 안겐반텐 포르슝 에. 베. 차동 사운드 재생
KR101892564B1 (ko) 2015-04-10 2018-10-04 프라운호퍼 게젤샤프트 쭈르 푀르데룽 데어 안겐반텐 포르슝 에.베. 차동 사운드 재생
RU2704635C2 (ru) * 2015-04-10 2019-10-30 Фраунхофер-Гезелльшафт Цур Фердерунг Дер Ангевандтен Форшунг Е.Ф. Дифференциальное воспроизведение звука
US10516937B2 (en) 2015-04-10 2019-12-24 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Differential sound reproduction
US10306358B2 (en) 2015-04-27 2019-05-28 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Sound system
RU2710524C2 (ru) * 2015-04-27 2019-12-26 Фраунхофер-Гезелльшафт Цур Фердерунг Дер Ангевандтен Форшунг Е.Ф. Звуковая система
WO2018023150A1 (fr) * 2016-08-01 2018-02-08 Blueprint Acoustics Pty Ltd Appareil de gestion de la distorsion dans un trajet de signal et procédé
US11089401B2 (en) 2016-08-01 2021-08-10 Blueprint Acoustics Pty Ltd Apparatus for managing distortion in a signal path and method
WO2024054834A3 (fr) * 2022-09-07 2024-04-18 Sonos, Inc. Imagerie spatiale sur des dispositifs de lecture audio

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