Electroacoustical transducing with low frequency augmenting devices

• US 20040105559A1
• Filed: 03/07/2003
• Published: 06/03/2004
• Est. Priority Date: 12/03/2002
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Aylward, J. Richard, Barker, Charles R. III
• Granted Patent: US 7,676,047 B2
• Time in Patent Office: Days
• US Class Current: 381/103
• CPC Class Codes: A63F 2300/6063 for sound processing
• CPC Class Codes: H03G 5/165 Equalizers; Volume or gain control in limited frequency bands
• CPC Class Codes: H04R 1/24 Structural combinations of separate transducers or of two parts of the same transducer and responsive respectively to two or more frequency ranges
• CPC Class Codes: H04R 1/26 Spatial arrangements of separate transducers responsive to two or more frequency ranges
• CPC Class Codes: H04R 1/2819 for loudspeaker transducers
• CPC Class Codes: H04R 1/2857 for loudspeaker transducers
• CPC Class Codes: H04R 2205/022 Plurality of transducers corresponding to a plurality of sound channels in each earpiece of headphones or in a single enclosure
• CPC Class Codes: H04R 2205/024 Positioning of loudspeaker enclosures for spatial sound reproduction
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 5/02 Spatial or constructional arrangements of loudspeakers
• CPC Class Codes: H04R 9/063 using a plurality of acoustic drivers H04R1/24 and H04R1/403 take precedence
• CPC Class Codes: H04S 1/002 Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution control circuits for electronic adaptation of the sound field H04S7/30
• CPC Class Codes: H04S 2420/01 Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]
• CPC Class Codes: H04S 3/00 Systems employing more than two channels, e.g. quadraphonic H04S5/00, H04S7/00 take precedence
• CPC Class Codes: H04S 3/002 Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution control circuits for electronic adaptation of the sound field H04S7/30

Abstract

A method for processing a multichannel audio signal. The method includes mounting electroacoustical transducers in a low frequency augmenting device. The electroacoustical transducers radiate different high frequency acoustic energy and common low frequency acoustic energy. The transducers may be part of directional arrays. The method is applied to multimedia entertainment devices.

Claims

1. A multimedia entertainment system, comprising

a first and a second multimedia entertainment device, each comprising:

a first input terminal for receiving a first channel audio signal;

a second input terminal for receiving an second channel audio signal;

dynamic equalizing circuitry for dynamically equalizing said first channel audio signal and said second channel audio signal to provide a dynamically equalized first channel signal and a dynamically equalized second channel signal said dynamic equalizing circuitry comprising

a first attenuator for attenuating a dynamic equalizer input audio signal by a variable factor G, where 0<

G<

1 to provide a first attenuated dynamic equalizer signal;

a second attenuator for attenuating said dynamic equalizer input audio signal, by a variable factor 1−

G to provide a second attenuated dynamic equalizer signal;

an equalizer, for equalizing said first attenuated dynamic equalizer signal to provide an equalized first attenuated dynamic equalizer signal; and

a dynamic equalizer combiner, for combining said equalized first attenuated dynamic equalizer signal with said second attenuated signal to provide a dynamic equalizer output signal;

clipping and post-clipping processing circuitry for clipping said dynamically equalized first channel signal and said dynamically equalized second channel signal to provide a clipped first channel signal and a clipped second channel signal, said clipping and post clipping processing circuitry comprising

a clipper, for clipping a clipper input audio signal to provide a clipped audio signal;

a first clipper filter, for filtering said clipper input audio signal to provide a filtered unclipped audio signal;

a second clipper filter for filtering said clipped audio signal to provide a filtered clipped audio signal;

a first clipper combiner, for differentially combining said filtered clipped audio signal and said clipped audio signal to provide a differentially combined clipper audio signal; and

a second clipper combiner for combining said filtered unclipped audio signal and said differentially combined audio signal to provide a clipper output signal;

a first separator, for separating said first clipped first channel audio signal into a first channel high frequency signal and a first channel low frequency signal;

a first separator, for separating said clipped first channel signal into a first channel high frequency signal and a first channel low frequency signal;

a second separator, for separating said clipped second channel signal into a second channel high frequency signal and a second channel low frequency signal;

a first processor, for processing said first channel high frequency signal to provide a processed first channel signal and a first channel canceling signal, wherein said first channel canceling signal is time-delayed and polarity inverted relative to said processed first channel signal;

a second processor, for processing said second channel high frequency signal to provide a processed second channel signal and a second channel canceling signal, wherein said second channel canceling signal is time-delayed and polarity inverted relative to said processed second channel signal

a first signal combiner, for combining said processed first channel signal and said first channel low frequency signal to provide a first channel output signal;

a second signal combiner, for combining said first channel canceling signal and said first channel low frequency signal to provide a first channel canceling output signal;

a third signal combiner, for combining said processed second channel signal and said second channel low frequency signal to provide a second channel output signal;

a fourth signal combiner, for combining said second channel canceling signal and said second channel low frequency signal to provide a second channel canceling output canceling signal;

a first electroacoustical transducer, for transducing said first channel output signal to provide a first channel sound wave;

a second electroacoustical transducer, for transducing said first channel canceling output signal to provide a first channel canceling output sounds wave, wherein said first electroacoustical transducer and said second electroacoustical transducer are positioned such that said first channel canceling output sound wave destructively interferes in a first direction and does not destructively interfere in a second direction, wherein said second direction is toward a listening space associated with said multimedia entertainment device and wherein said first electroacoustical transducer and said second electroacoustical transducer are mounted in a low frequency augmenting device so that said first channel output sound wave and said first channel canceling sound wave are radiated into said low frequency augmenting device;

a third electroacoustical transducer, for transducing said second channel output signal to provide a second channel sound wave;

a fourth electroacoustical transducer, for transducing said second channel canceling output signal to provide a second channel canceling output sounds wave, wherein said third electroacoustical transducer and said fourth electroacoustical transducer are positioned such that said second channel canceling output sound wave destructively interferes in a third direction and does not destructively interfere in a fourth direction, wherein said fourth direction is toward a listening space associated with said multimedia entertainment device and wherein said third electroacoustical transducer and said fourth electroacoustical transducer are mounted in a low frequency augmenting device so that said second channel output sound wave and said second channel canceling sound wave are radiated into said low frequency augmenting device;

circuitry for modifying said first channel output signal and said first channel output signal to modify the orientation of said first direction; and

circuitry for modifying said second channel output signal and said second channel canceling output signal to modify the orientation of said third direction;

a network, for communicatingly coupling said first and second multimedia entertainment devices.

2. A method for processing audio signals, comprising:

receiving a first channel audio signal;

separating said first audio channel signal into a first channel first spectral portion and a first channel second spectral portion;

a first processing, of said first channel signal first spectral portion, according to a first process represented by a first non-unity non-zero transfer function to provide a first channel first processed signal;

a second processing, of said first channel first spectral portion, according to a second process represented by a second transfer function, different from said first transfer function, to provide a first channel second processed signal;

combining said first channel first processed signal and said first channel second spectral portion to provide a first channel first combined signal;

transducing, by a first electroacoustical transducer, said first combined signal;

combining said first channel second processed signal and said first channel second spectral portion to provide a first channel second combined signal; and

transducing, by a second electroacoustical transducer, said second combined signal.

3. A method for processing an audio signal in accordance with claim 2, wherein said first transfer function comprises delaying said first channel first spectral portion so that said first channel first processed signal is time delayed relative to said first channel second processed signal and wherein said first transfer function comprises polarity inverting said first channel audio signal first spectral portion so that said first channel first processed signal is polarity inverted relative to said first channel second processed signal.

4. A method for processing an audio signal in accordance with claim 3, wherein said first transfer function and said second transfer function comprise head related transfer functions.

5. A method for processing an audio signal in accordance with claim 2 further comprising:

receiving a second channel audio signal;

separating said second channel audio signal into a second channel first spectral portion and a second channel second spectral portion;

processing said second channel first spectral portion according to a first process represented by a third non-unity non-zero transfer function to provide a second channel first processed signal;

processing said second channel audio signal first spectral portion according to a second process represented by a fourth transfer function, different from said third transfer function, to provide a second channel second processed signal;

combining said second channel first processed signal and said second channel second spectral portion to provide second channel first combined signals;

transducing, by a third electroacoustical transducer, said second channel first combined signals;

combining said second channel audio second processed signals and said second channel second spectral portion to provide second channel second combined signals; and

transducing, by a fourth electroacoustical transducer, said second channel second combined signals.

6. A method for processing an audio signal in accordance with claim 5, wherein said third transfer function comprises delaying said second channel first spectral portion so that said second channel first processed signal is time delayed relative to said second channel second processed signal and wherein said third transfer comprises polarity inverting said second channel first spectral portion so that said second channel first processed signal is polarity inverted relative to said second channel second processed signal.

7. A method for processing an audio signal in accordance with claim 6, wherein said third transfer function and said fourth transfer function comprise head related transfer functions.

8. A method for processing a multichannel audio signal, comprising:

separating a first audio channel signal stream into a first channel first spectral portion and a first channel second spectral portion;

separating a second audio channel signal stream into a second first spectral portion and a second channel second spectral portion;

processing said first channel signal first spectral portion according to a first process represented by a first non-unity non-zero transfer function to provide a first processed signal;

processing said first audio channel signal first spectral portion according to a second process represented by a second transfer function different from said first transfer function to provide a second processed signal;

processing said second channel first spectral portion according to a third process represented by a third non-unity non-zero transfer function to provide a third processed signal;

processing said second channel signal first spectral portion according to a fourth process represented by a fourth transfer function different from said third transfer function to provide a fourth processed signal;

combining said first channel second spectral portion and said second channel second spectral portion to provide a combined first channel second spectral portion;

transducing, by a first electroacoustical transducer, said first channel combined second spectral portion and a one of said first channel first processed signal, said first channel second processed signal, said first channel third processed signal and said first channel fourth processed signal.

9. A method for processing a multichannel audio signal stream in accordance with claim 8, further comprising transducing, by a second electroacoustical transducer, said first channel combined second spectral portion and a second one of said first processed signal, said second processed signal, said third processed signal and said fourth processed signal.

10. A method for processing multichannel audio signals in accordance with claim 9, wherein said first and second channels are a left channel and a right channel, and wherein said first and second electroacoustical transducers are positioned in front of a listener, further comprising

separating a third audio channel signal into a third channel first spectral portion and a third channel second spectral portion;

separating a fourth audio channel signal into a fourth channel first spectral portion and a fourth channel second spectral portion;

processing said third audio channel signal first spectral portion according to a fifth process represented by a fifth non-unity non-zero transfer function to provide a fifth processed signal;

processing said third channel first spectral portion according to a sixth process represented by a transfer function different from said fifth transfer function to provide a sixth processed signal;

processing said fourth channel signal first spectral portion according to a seventh process represented by a seventh non-unity non-zero transfer function to provide a seventh processed signal;

processing said fourth audio channel first spectral portion according to an eighth process represented by a transfer function different from said seventh transfer function to provide an eighth processed signal;

combining said third audio channel second spectral portion and said fourth audio channel second spectral portion to provide a second combined second spectral portion;

transducing, by a third electroacoustical transducer positioned behind said listener, said second combined second spectral portion and a one of said fifth processed signal, said sixth processed signal, said seventh processed signal and said eighth processed signal.

11. A method for processing multichannel audio signals in accordance with claim 8, wherein one of said processing said first audio channel first spectral portion comprises at least one of a group of processes consisting of attenuating, amplifying, delaying, and equalizing.

12. An electroacoustical device, comprising:

a first directional array, said first directional array comprising a first electroacoustical transducer and a second electroacoustical transducer, said first and second electroacoustical transducers each comprising a first radiating surface and a second radiating surface; and

a low frequency augmenting structure having an interior and an exterior

wherein said electroacoustical device is constructed and arranged so that said first electroacoustical transducer first radiating surface and said second electroacoustical transducer first radiating surface face a surrounding environment and so that said first electroacoustical transducer second radiating surface and said second electroacoustical transducer second radiating surface face said low frequency augmenting structure interior.

13. An electroacoustical device in accordance with claim 12, further comprising:

a second directional array, said second directional array comprising a third electroacoustical transducer and a fourth electroacoustical transducer, said third and fourth electroacoustical transducers each comprising a first radiating surface and a second radiating surface;

wherein said electroacoustical device is constructed and arranged so that said third electroacoustical transducer first radiating surface and said fourth electroacoustical transducer first radiating surface face said surrounding environment and so that said third electroacoustical transducer second radiating surface and said fourth electroacoustical transducer second radiating surface face said low frequency augmenting structure interior.

14. An electroacoustical device in accordance with claim 12, wherein said low frequency augmenting device comprises one of an acoustical waveguide and a ported enclosure.

15. A method for operating a multichannel audio system, said multichannel audio system comprising a first and second electroacoustical transducer and an acoustic waveguide, said method comprising:

positioning said first transducer and said second transducer at separated points in said waveguide so that a first radiating surface of said first transducer and a first radiating surface of said a second transducer radiate sound waves into said acoustic waveguide;

separating a first channel signal into a first channel high frequency audio signal and a first channel low frequency audio signal;

separating a second channel signal into a second channel high frequency audio signal and a second channel low frequency audio signal;

combining said first channel low frequency audio signal and said second channel low frequency audio signal to form a common low frequency audio signal;

transmitting said common low frequency audio signal to said first transducer and said second transducer;

transmitting said first channel high frequency audio signal to said first transducer;

transmitting said second channel high frequency audio signal to said second transducer;

radiating into said waveguide, by said first transducer, sound waves corresponding to said first channel high frequency signal and said common low frequency audio signal;

radiating into said waveguide, by said second transducer, sound waves corresponding to said second channel high frequency signal and said common low frequency audio signal.

16. A method for operating an audio system in accordance with claim 15, said acoustic waveguide having an effective length, wherein said positioning step includes positioning first transducer so that when said first transducer radiates into said waveguide a first sound wave having a wavelength substantially equal to said effective length, said second transducer radiates a second sound wave into said waveguide so that said second sound wave has a substantially opposing phase to said first sound wave.

17. A method for operating an audio system in accordance with claim 16, positioning said first transducer so that a second radiating surface of said first transducer radiates sound waves to the external environment by a direct path absent said waveguide.

18. A method for operating a multimedia entertainment device laving an audio system having a first and a second loudspeaker array and a first and second audio channel, said first and second audio channels each having a high frequency portion and a low frequency portion, said multimedia entertainment device including an associated listening space, said method comprising:

radiating directionally toward said listening space, by said first loudspeaker array, sound waves corresponding to said first audio channel high frequency portion;

radiating directionally toward said listening space, by said second loudspeaker array, sound waves corresponding to said second audio channel high frequency portion; and

radiating non-directionally, by said first loudspeaker array and said second loudspeaker array, said first channel low frequency portion and said second channel low frequency portion.

19. A method for operating a multimedia entertainment device in accordance with claim 18, wherein said multimedia entertainment device is a video game.

20. A method for operating a multimedia entertainment device in accordance with claim 18, wherein said multimedia entertainment device is a gambling machine.

21. An entertainment area comprising:

a first multimedia entertainment device comprising an audio system, said audio system comprising a first audio channel and a second audio channel, said first audio channel and said second audio channel each comprising a high frequency portion and a low frequency portion, said first multimedia entertainment device comprising a first loudspeaker array and a second loudspeaker array, said entertainment area including a listening space associated with said first multimedia entertainment device;

a second multimedia entertainment device comprising an audio system, said audio system comprising a first audio channel and a second audio channel, said first audio channel and said second audio channel each comprising a high frequency portion and a low frequency portion, said second multimedia entertainment device comprising a first loudspeaker array and a second loudspeaker array, said entertainment area including a listening space associated with said second multimedia entertainment device;

wherein said first multimedia entertainment device and said second multimedia training device are in a common listening area;

wherein said first multimedia entertainment device is constructed and arranged to radiate sound waves corresponding said first device first channel high frequency portion and said first device second channel high frequency port ion directionally so that said sound waves corresponding to said first device first channel high frequency portion and said sound waves corresponding to said first device second channel high frequency portion are significantly more audible in said listening space associated with said first device than in said listening space associated with said second device; and

wherein said second multimedia entertainment device is constructed and arranged to radiate sound waves corresponding said second device first channel high frequency portion and said second device second channel high frequency portion directionally so that said sound waves corresponding to said second device first channel high frequency portion and said second device second channel high frequency portion are significantly more audible in said listening space associated with said second device than in said listening space associated with said first device.

22. An entertainment area in accordance with claim 21, wherein said entertainment area is a gambling casino and wherein said first and second multimedia entertainment devices are gambling devices.

23. An entertainment area in accordance with claim 22 further comprising a control device, wherein said gambling devices are networked with each other and with said control device so that first multimedia gambling device and said second multimedia gambling device are controllable from said control device.

24. An entertainment area in accordance with claim 21, further comprising a control device, wherein said first and second multimedia entertainment devices are networked with each other and with said control device so that first multimedia entertainment device and said second multimedia gambling device are controllable from said control device.

25. An audio system for radiating sound waves corresponding to a first audio signal and a second audio signal, said audio system including an indicator for indicating a directional radiation pattern preference, said indicator having at least two states, said audio system comprising:

a detector for detecting said indicator;

a directional array for radiating sound waves in a plurality of directional radiation patterns,

wherein said directional array is constructed an arranged to radiate acoustic energy according to a first directional radiation pattern upon the detection of a first indicator state to radiate acoustic energy according to said second directional radiation pattern upon the detection of a second indicator state.

26. An audio system in accordance with claim 25, wherein said indicator comprises relative phase of a first audio channel and a second audio channel.

27. An audio system in accordance with claim 25, wherein said indicator comprises an absolute value of a signal amplitude.

28. An audio system in accordance with claim 25, wherein said directional radiation pattern is continuously variable between said first directional radiation pattern and said second directional radiation pattern.

29. An audio system in accordance with claim 25, wherein said directional radiation pattern is incrementally variable between said first directional radiation pattern and said second directional radiation pattern.

30. An audio system in accordance with claim 25, wherein said directional array is constructed and arranged to radiate more acoustic energy corresponding to said first signal in a first direction than in a second direction according to said first radiation pattern and wherein said directional array is constructed and arranged to radiate more acoustic energy corresponding to said first signal in said second direction than in said first direction according to said second radiation pattern.

31. An audio system in accordance with claim 30, wherein said first signal comprises an audio channel signal and said second signal comprises a time delayed said audio channel signal.

32. An audio system in accordance with claim 30, wherein said directional array is constructed an arranged to radiate more acoustic energy corresponding to said second signal in said second direction than in said first direction according to said first radiation pattern and to radiate more acoustic energy corresponding to said second channel signal in said first direction than in said second direction according to said second radiation pattern.

33. An audio system in accordance with claim 32, wherein said first signal comprises an audio channel signal and said second signal comprises a time delayed said audio channel signal.

34. An audio system in accordance with claim 25, wherein said first directional pattern is directional in a first direction and said second directional pattern is substantially non-directional.

35. A method for dynamically equalizing an audio signal, comprising:

providing an audio signal;

a first attenuating, of said audio signal, by a variable factor G, where 0<

G<

1 to provide a first attenuated signal;

a second attenuating, of said audio signal, by a variable factor 1−

G to provide a second attenuated signal;

equalizing said first attenuated signal to provide an equalized first attenuated signal; and

combining said equalized first attenuated signal with said second attenuated signal to provide an output signal.

36. A method for dynamically equalizing an audio signal in accordance with claim 35, wherein said second attenuating comprises:

combining differentially said first attenuated audio signal and said first audio signal to provide said second attenuated signal.

37. A method for an equalizing audio signal in accordance with claim 35, wherein said audio signal is a compressed audio signal and wherein providing said signal comprises:

attenuating an input audio signal by a factor C that is responsive to the amplitude of said input audio signal to provide an attenuated input audio signal;

applying a gain K2 to said attenuate input audio signal to provide said compressed audio signal.

38. A method for equalizing an audio signal in accordance with claim 37, wherein said the value of factor C is responsive to the absolute value of the amplitude of said input audio signal.

39. A method for equalizing an audio signal in accordance with claim 38, wherein the value of said factor G is responsive to said value of said factor C.

40. A method for equalizing an audio signal in accordance with claim 35, wherein the value of said factor G is responsive to the amplitude of said audio signal.

41. A method for clipping and post-clipping processing an audio signal, comprising:

clipping an audio signal to provide a clipped audio signal;

filtering, by a first filter, said audio signal to provide a filtered unclipped audio signal;

filtering, by a second filter, said clipped audio signal to provide a filtered clipped audio signal;

differentially combining said filtered clipped audio signal and said clipped audio signal to provide a differentially combined audio signal; and

combining said filtered unclipped audio signal and said differentially combined audio signal to provide an output signal.

42. A method for clipping an audio signal in accordance with claim 41, wherein said first filter is a notch filter.

43. A method for clipping an audio signal in accordance with claim 42, wherein said second filter is a notch filter.

44. A method for clipping an audio signal in accordance with claim 43 wherein said first filter and said second filter have substantially the same notch frequency.

45. A method for controlling the directivity of a sound radiation pattern, comprising:

providing an audio signal to a first attenuator, a time delay, and a first summer;

a first attenuating, by said first attenuator by a variable factor G, where 0<

G<

1 of said audio signal to provide a first variably attenuated audio signal;

a second attenuating, by a variable factor (1−

G) of said audio signal to provide a second variably attenuated audio signal;

time delaying said first audio signal to provide a delayed audio signal;

a third attenuating, by a variable factor H, of said delayed audio signal to provide a first variably attenuated delayed audio signal;

a fourth attenuating, by a variable factor (1−

H) to provide a second variably attenuated delayed audio signal;

combining said first variably attenuated audio signal with said second variably attenuated delayed audio signal to provide a first transducible audio signal; and

combining said second variably attenuated audio signal with said first variably attenuated delayed audio signal to provide a second transducible audio signal.

46. A method for controlling the directivity of a sound radiation pattern in accordance with claim 45, wherein said second attenuating comprises:

differentially combining said first variably attenuated audio signal and said input audio signal to provide said second variably attenuated audio signal.

47. A method for controlling the directivity of a sound radiation pattern in accordance with claim 46, wherein said fourth attenuating comprises:

differentially combining said first variably attenuated delayed audio signal with said delayed audio signal to provide said second attenuated delayed audio signal.

48. A method for controlling the directivity of a sound radiation pattern in accordance with claim 47, wherein G=H.

49. A method for controlling directivity of a loudspeaker array in accordance with claim 48 wherein

50. A gambling device comprising:

an associated listening space;

and an audio system, said audio system comprising a directional loudspeaker array comprising a plurality of transducers and wherein sound waves radiated by a first of said plurality of transducers combines constructively in a first direction and combines destructively in a second direction, and wherein said first direction is toward said listening space.