WO1998058522A2 - Sound reproduction system - Google Patents
Sound reproduction system Download PDFInfo
- Publication number
- WO1998058522A2 WO1998058522A2 PCT/GB1998/001527 GB9801527W WO9858522A2 WO 1998058522 A2 WO1998058522 A2 WO 1998058522A2 GB 9801527 W GB9801527 W GB 9801527W WO 9858522 A2 WO9858522 A2 WO 9858522A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- loudspeakers
- centre line
- virtual
- sound
- source
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04S—STEREOPHONIC SYSTEMS
- H04S3/00—Systems employing more than two channels, e.g. quadraphonic
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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
- H04S—STEREOPHONIC SYSTEMS
- H04S2400/00—Details of stereophonic systems covered by H04S but not provided for in its groups
- H04S2400/01—Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04S—STEREOPHONIC SYSTEMS
- H04S2420/00—Techniques used stereophonic systems covered by H04S but not provided for in its groups
- H04S2420/01—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]
Definitions
- This invention relates to sound reproduction systems, and in particular to an improved system for binaural synthesis, that is the generation of sound signals such that the pressures at a user's ears correspond to those which would have existed in the presence of the sound source to be simulated.
- Such sounds will have a true source, which is generally a loudspeaker or array of loudspeakers, but seem to the listener to originate from another source, located at the position of the source being simulated This perceived source of the sound is known as a "virtual source”.
- each loudspeaker L1 , L2 to each ear of a listener Z is represented in Figure 1 , and can be characterised by the following matrix equations: ⁇ L H 1 L H 2L Yl where-
- X is the signal received at the left ear
- X R is the signal received at the right ear
- Y ⁇ is the signal transmitted by the left source (loudspeaker L1 );
- a sound reproduction system for reproducing sound, the system comprising a plurality of loudspeakers, a processor capable of determining where, within a defined space, a virtual sound source is located and, for each virtual sound source, means for selecting a sub-set of the loudspeakers, said sub-set being selected from the plurality of loudspeakers on the basis of the location of the virtual sound source in the defined space, and means for applying a cross talk cancellation process to the selected sub-set of the loudspeakers.
- a method of sound reproduction for reproducing sound by way of a plurality of speakers comprising the steps of determining where, within a defined space, a virtual sound source is located and, for each virtual sound source, applying a cross talk cancellation process to a sub-set of the loudspeakers, said sub-set being selected from the plurality of loudspeakers on the basis of the location of the virtual sound source in the defined space.
- the plurality of loudspeakers from which the subset is selected allows accurate simulation over a greater range of virtual source locations than a single pair of loudspeakers could achieve.
- the selection of a subset (preferably a pair) from this larger plurality of loudspeakers allows the crosstalk processing to be greatly simplified.
- the pairwise concept introduced here embraces a finite number of independent crosstalk cancellation processes, each identifying with a pair of loudspeakers in a multiple speaker array.
- the derivation of the crosstalk cancellation matrix process for each pair is identical to that for a conventional pair.
- the number of independent crosstalk cancellation matrix modules which can be implemented in such an array is governed by the locations of loudspeakers in the multi-loudspeaker array, and the spatial coverage and accuracy achievable by an optimised pair of loudspeakers in that array.
- Figure 1 shows a conventional stereo pair configuration with the respective transfer functions from sources to ears as already discussed
- Figure 2 illustrates four physical point sources with maximum possible number of crosstalk cancellation processes
- Figure 3 illustrates a lateral set of four loudspeakers, showing the loudspeakers' area of coverage on the lateral plane (the horizontal plane containing the ears);
- Figure 4 illustrates the application of binaurally synthesised signals to appropriate crosstalk cancellation processes for the configuration of Figure 3;
- Figure 5 illustrates a three loudspeaker configuration
- Figure 6 illustrates a five loudspeaker configuration
- Figure 7 illustrates an application of virtual static point sources to overcome limitations in available space
- Figure 8 illustrates another four-loudspeaker configuration
- Figure 9 shows schematically a pairwise crosstalk cancellation implementation circuit for localising five monophonic virtual sources using the four- loudspeaker layout of Figure 8.
- Figure 2 shows a loudspeaker layout having four loudspeakers L1 , L2, L3, L4. It is not in general necessary to implement all the possible pairwise processes, as in most configurations only adjacent pairs of loudspeakers are used, but for some virtual sources non-adjacent pairs may be selected (as will be seen when discussing Figure 6) so the maximum number of crosstalk cancellation processes between pairs of loudspeakers in an array of four loudspeakers is not four, but six, or more generally, for an array of n loudspeakers, n(n- 1)/2.
- the selection of an appropriate crosstalk cancellation process is governed by the direction of the synthesised sound source or sources, i.e. if synthesised sound images are to emanate from directions which are covered by one pair of loudspeakers, the processed directional signals are only applied to that pair of loudspeakers and its respective crosstalk cancellation process. If two or more sound sources of different directions are to be synthesised and played back via an array of multiple loudspeakers, respective crosstalk cancellation process modules relating to respective pairs of loudspeakers can be implemented to deliver each pair of directional signals to the ears, taking note that the process is always performed pairwise.
- each pair of signals is applied to crosstalk cancellation process modules of appropriate pairs of loudspeakers which cover the location of the sound images.
- loudspeaker L1 ,L2 encompassing the frontal sector 31 ( ⁇ 60°), L1 ,L3 and L2,L4 for left and right sectors 32, 33 respectively and L3,L4 for rear coverage (sector 34).
- the block diagram in Figure 4 illustrates the strategic switching of a number of processed signals having left and right components (X L , X R ) as heard at the ears to appropriate modules 41 , 42, 43, 44, each corresponding to the pair of the loudspeakers appropriate to the lateral bearings of these signals.
- Translating virtual moving sound sources using the pairwise concept can be achieved by correctly switching or directing the synthesised signals to the appropriate pairwise crosstalk cancellation process.
- a sound source can be made to translate from the left sector (32) to the frontal sector (31 ), by first applying the synthesised signal to the crosstalk cancellation processor 42 for the left sector 32, to give its initial position as well as the points of movement within the left sector, depending on the angular step size between synthesised sources. Once the image shifts to the next sector, the synthesised signals are switched to the crosstalk cancellation processor 41 for the front sector 31 to continue projecting the moving source.
- the example shown above may appear to suggest that the pairwise concept restricts the crosstalk cancellation to within the angle between the pair of loudspeakers.
- the angle of coverage be it lateral or spherical, strictly depends on how well a pair of loudspeakers can spatialise within its capability (in the sense of localisation accuracy) .
- the following worked examples were taken from experiments which demonstrate that different paired configurations gave significantly different localisation abilities and reveal advantages of some unconventional loudspeaker placement over current layout practice.
- FIG. 5 An unusual layout, which may seem to be impractical on initial inspection, is shown in Figure 5.
- This has just three loudspeakers L1 , L2, L3 (Left, Centre Front, and Right), arranged at 0° (Centre Front) and ⁇ 90° (Right and Left). It displays good imaging ability within the respective loudspeakers' optimised fields of coverage as shown in Figure 5.
- the left and right frontal quadrants 51 , 52 covered by the Left/Centre pair L1 /L2 and Right/Centre pair L2/L3 give good static frontal sources even with a distinct degree of head rotation to face the virtually positioned source.
- the unconventional Left/Right pair L1 /L3 along the axis of the ears gave remarkable rear incidence synthesised images covering the range from + 90° to -90°, even on the onsets of the synthesised sound sample.
- the Left- Right ear axis loudspeaker pair L1 /L3 not only gives coverage along the rear half of the lateral plane (sector 53), but it also encompasses the rear hemisphere, i.e. including point sources above or below the lateral plane.
- FIG. 6 Another example is illustrated in Figure 6. This illustrates that the coverage provided by some paired loudspeakers is limited but, by combining with several other pairs of loudspeakers in the array, the voids are filled and a desired spatia sation is fulfilled
- Five loudspeakers are used, arranged at 0° (Centre-Front: L2) ⁇ 60° (Right-Front: L3, and Left-Front: L1 ), and ⁇ 1 20° (Right-Rear: L4 and Left-Rear: L5) .
- the frontal ⁇ 60° stereo pair L1 /L3 provide poor frontal images in the range covering +1 0° (sectors 62/63) .
- the pairwise concept employs a strategy of applying the best pair available to achieve good localisation and in this case, subjective tests have shown that sound images projected at the angles between -1 0° and -60° (sector 61 ) and between + 1 0° and + 60° (sector 64) are better localised using the left- front/ ⁇ ght-front non-adjacent pair L1 /L3 than that processed by either the left- front/centre-front or centre-front/ ⁇ ght-front pairs (L1 /L2, L2/L3) .
- the pairwise concept is not restricted to just these few loudspeaker configurations and locations.
- the invention delivers a new but yet direct general approach to solving three-dimensional sound field spatiahsation for multiple loudspeaker applications.
- the loudspeaker array itself may be designed to comply with other constraints such as cost (in particular the number of loudspeakers to be used) and the availability of locations to site the loudspeakers.
- cost in particular the number of loudspeakers to be used
- locations to site the loudspeakers.
- the best localisation effect of a sound source is achieved by engaging a crosstalk cancellation process that relates to the most appropriate pair of loudspeakers available in the array. This does not restrict to just the direct path of sound sources
- Each individual reflection of a sound source could be treated as a further virtual source, with a suitable delay with respect to the primary source, to simulate a reflected sound
- Applying the appropriate crosstalk cancellation process to each reflection could accurately render their positions in space, an essence of an immersive spatial environment.
- Directional loudspeakers can be used to reduce the volume of sound audible at locations away from the listener Z, and in particular at the locations of the virtual rear surround units 74, 75 outside the room R.
- Figure 9 shows the array set up with pairwise crosstalk cancellation applied to a forward pair L1 , L2 set at ⁇ 60° and a side pair L3, L4 set at ⁇ 90° , i.e. it is based on the assumption that the forward pair L1 , L2 provides the best reconstruction of spatiahsed images in the front sector (Sector 81 ) and the side pair L3, L4 provides the best reconstruction of spatiahsed images in the rear sector (Sector 82) .
- the example depicts five virtual sources X 0 , X 1 ( X 2 , X 3 , X 4 to be spatiahsed, however the implementation of the pairwise concept does not limit the number of input sources.
- the input sources X 0 - X 4 are each first subjected to analogue/digital conversion in a bank 91 of converters A/D. The input sources are then treated in a bank of processors 92 with the appropriate hearing response transfer functions
- H XO IS the HRTF of source X 0 to Left Ear
- H X0R is the HRTF of source X 0 to Right Ear, etc.
- the left outputs of the front three sources X 0L X 1 , X 2 are then combined in a combiner 93, and similarly for the right outputs X 0 XI R, X 2 R, (combiner 93a) and the two outputs filtered in a processor 94 by the forward pair crosstalk cancellation matrix for the reconstruction of virtual images in the front sector 81 .
- the remaining two input sources X 3 , X 4 are similarly filtered by the side pair crosstalk cancellation matrix (processor 94a) for the reconstruction of virtual images in the rear sector 82.
- the outputs from the cancellation stages 94, 94a are then subject to digital/analogue conversion (D/A) (convertors 96) for output to the appropriate loudspeakers L1 , L2; L3, L4
- H 1 L HRTF of Loudspeaker L1 to Left Ear
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Stereophonic System (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU76644/98A AU735233B2 (en) | 1997-06-19 | 1998-05-27 | Sound reproduction system |
DE69816298T DE69816298T2 (en) | 1997-06-19 | 1998-05-27 | A sound reproduction |
EP98924440A EP0990369B1 (en) | 1997-06-19 | 1998-05-27 | Sound reproduction system |
JP50392399A JP2002505057A (en) | 1997-06-19 | 1998-05-27 | Sound reproduction system |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP97304310 | 1997-06-19 | ||
EP97304310.2 | 1997-06-19 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO1998058522A2 true WO1998058522A2 (en) | 1998-12-23 |
WO1998058522A3 WO1998058522A3 (en) | 1999-03-11 |
Family
ID=8229384
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1998/001527 WO1998058522A2 (en) | 1997-06-19 | 1998-05-27 | Sound reproduction system |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0990369B1 (en) |
JP (1) | JP2002505057A (en) |
AU (1) | AU735233B2 (en) |
DE (1) | DE69816298T2 (en) |
WO (1) | WO1998058522A2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006016156A1 (en) * | 2004-08-10 | 2006-02-16 | 1...Limited | Non-planar transducer arrays |
US7078423B2 (en) | 2002-07-18 | 2006-07-18 | Inotek Pharmaceuticals Corporation | 5-Aryltetrazole compounds, compositions thereof, and uses therefor |
US7087631B2 (en) | 2002-07-18 | 2006-08-08 | Inotek Pharmaceuticals Corporation | Aryltetrazole compounds, and compositions thereof |
EP2229012A1 (en) * | 2009-03-11 | 2010-09-15 | Yamaha Corporation | Device, method, program, and system for canceling crosstalk when reproducing sound through plurality of speakers arranged around listener |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015002517A1 (en) * | 2013-07-05 | 2015-01-08 | 한국전자통신연구원 | Virtual sound image localization method for two dimensional and three dimensional spaces |
WO2019079602A1 (en) * | 2017-10-18 | 2019-04-25 | Dts, Inc. | Preconditioning audio signal for 3d audio virtualization |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5517570A (en) * | 1993-12-14 | 1996-05-14 | Taylor Group Of Companies, Inc. | Sound reproducing array processor system |
US5598478A (en) * | 1992-12-18 | 1997-01-28 | Victor Company Of Japan, Ltd. | Sound image localization control apparatus |
-
1998
- 1998-05-27 AU AU76644/98A patent/AU735233B2/en not_active Ceased
- 1998-05-27 WO PCT/GB1998/001527 patent/WO1998058522A2/en active IP Right Grant
- 1998-05-27 DE DE69816298T patent/DE69816298T2/en not_active Expired - Fee Related
- 1998-05-27 EP EP98924440A patent/EP0990369B1/en not_active Expired - Lifetime
- 1998-05-27 JP JP50392399A patent/JP2002505057A/en active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5598478A (en) * | 1992-12-18 | 1997-01-28 | Victor Company Of Japan, Ltd. | Sound image localization control apparatus |
US5517570A (en) * | 1993-12-14 | 1996-05-14 | Taylor Group Of Companies, Inc. | Sound reproducing array processor system |
Non-Patent Citations (2)
Title |
---|
BAUCK J ET AL: "GENERALIZED TRANSAURAL STEREO AND APPLICATIONS" JOURNAL OF THE AUDIO ENGINEERING SOCIETY, vol. 44, no. 9, September 1996, pages 683-705, XP000699723 cited in the application * |
PULKII V: "VIRTUAL SOUND SOURCE POSITIONING USING VECTOR BASE AMPLITUDE PANNING" JOURNAL OF THE AUDIO ENGINEERING SOCIETY, vol. 45, no. 6, June 1997, pages 456-466, XP000695381 * |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7078423B2 (en) | 2002-07-18 | 2006-07-18 | Inotek Pharmaceuticals Corporation | 5-Aryltetrazole compounds, compositions thereof, and uses therefor |
US7087631B2 (en) | 2002-07-18 | 2006-08-08 | Inotek Pharmaceuticals Corporation | Aryltetrazole compounds, and compositions thereof |
US7135491B2 (en) | 2002-07-18 | 2006-11-14 | Inotek Pharmaceuticals Corp. | 5-Aryltetrazole compounds and uses thereof |
WO2006016156A1 (en) * | 2004-08-10 | 2006-02-16 | 1...Limited | Non-planar transducer arrays |
GB2431314A (en) * | 2004-08-10 | 2007-04-18 | 1 Ltd | Non-planar transducer arrays |
GB2431314B (en) * | 2004-08-10 | 2008-12-24 | 1 Ltd | Non-planar transducer arrays |
EP2229012A1 (en) * | 2009-03-11 | 2010-09-15 | Yamaha Corporation | Device, method, program, and system for canceling crosstalk when reproducing sound through plurality of speakers arranged around listener |
US8320590B2 (en) | 2009-03-11 | 2012-11-27 | Yamaha Corporation | Device, method, program, and system for canceling crosstalk when reproducing sound through plurality of speakers arranged around listener |
Also Published As
Publication number | Publication date |
---|---|
WO1998058522A3 (en) | 1999-03-11 |
EP0990369B1 (en) | 2003-07-09 |
DE69816298D1 (en) | 2003-08-14 |
AU735233B2 (en) | 2001-07-05 |
JP2002505057A (en) | 2002-02-12 |
AU7664498A (en) | 1999-01-04 |
EP0990369A2 (en) | 2000-04-05 |
DE69816298T2 (en) | 2004-05-27 |
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