Method and apparatus for capturing and rendering an audio scene
10469924 ยท 2019-11-05
Assignee
Inventors
Cpc classification
H04R1/025
ELECTRICITY
H04S2400/15
ELECTRICITY
H04R1/02
ELECTRICITY
H04S7/30
ELECTRICITY
International classification
H04R1/02
ELECTRICITY
H04R1/24
ELECTRICITY
H04S7/00
ELECTRICITY
Abstract
The method of capturing an audio scene includes acquiring sounds having first and second directivities to obtain first and second acquisition signals, respectively, the first directivity being higher than the second directivity, the steps of acquiring being performed simultaneously, and both acquisition signals together representing the audio scene; separately storing the first and second acquisition signals or mixing individual channels in the acquisition signals to obtain first and second mixed signal, respectively, and separately storing the first and second mixed signals, or transmitting the first and second mixed signals or the first and second acquisition signals to a loudspeaker setup and rendering the first mixed signal or the first acquisition signal using a loudspeaker arrangement having a first directivity and simultaneously rendering the second mixed signal or the second acquisition signal using a loudspeaker arrangement having a second directivity, the second loudspeaker directivity being lower than the first one.
Claims
1. A method of capturing an audio scene comprising a plurality of sound sources, comprising: acquiring first directivity sound from the plurality of the sound sources of the audio scene, the first directivity sound comprising a first directivity to achieve a first acquisition signal, the first acquisition signal comprising a high directivity sound portion from the plurality of sound sources of the audio scene; acquiring second directivity sound from the plurality of the sound sources of the audio scene, the second directivity sound comprising a second directivity to achieve a second acquisition signal, wherein the first directivity is higher than the second directivity, and wherein the second acquisition signal comprises a low directivity sound portion from the same plurality of the sound sources of the audio scene, wherein the steps of acquiring the first directivity sound and acquiring the second directivity sound are performed simultaneously, and wherein the first acquisition signal and the second acquisition signal together represent the audio scene comprising the plurality of the sound sources; and separately storing the first acquisition signal and the second acquisition signal; or separately transmitting the first acquisition signal and the second acquisition signal to a loudspeaker setup, wherein the step of acquiring the first directivity sound from the plurality of the sound sources of the audio scene, the first directivity sound having the first directivity, comprises placing a first set of microphones between places for the plurality of the sound sources of the audio scene and places for listeners to the audio scene comprising the plurality of the sound sources or directing a first set of directed microphones so that a maximum sensitivity of the first set of directed microphones is directed to the audio scene comprising the plurality of the sound sources and acquiring microphone signals from the first set as the first acquisition signal; wherein the step of acquiring the second directivity sound from the plurality of the sound sources of the audio scene, the second directivity sound having a second directivity, comprises placing a second set of microphones lateral to the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources or above the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources, where microphone signals from the second set are the second acquisition signal, and wherein the first acquisition signal does not have any contribution from the microphone signals from the second set, and wherein the second acquisition signal does not have any contribution from the microphone signals from the first set.
2. The method in accordance with claim 1, wherein the directivity is defined by a directivity factor as a ratio of radiated sound intensity at a remote point on a principle axis of a sound source of the plurality of the sound sources of the audio scene to an average intensity of the sound transmitted through a sphere passing through the remote point and concentric with the sound source of the plurality of the sound sources of the audio scene, wherein the first acquisition signal comprises a higher directivity factor than the second acquisition signal.
3. The method of claim 2, wherein the directivity factor related to the first acquisition signal is greater than 0.6, and wherein the directivity factor relative to the second acquisition signal is lower than 0.4.
4. A method of rendering an audio scene, comprising: providing a first mixed signal related to first directivity sound comprising the first directivity; providing a second mixed signal related to second directivity sound comprising the second directivity, wherein the second directivity is lower than the first directivity; generating a first sound signal from the first mixed signal using a first loudspeaker arrangement comprising a first loudspeaker directivity; generating a second sound signal from the second mixed signal by a second loudspeaker arrangement comprising a second loudspeaker directivity, wherein the steps of generating the first sound signal and the second sound signal are performed simultaneously, wherein the second loudspeaker directivity is lower than the first loudspeaker directivity, wherein the first mixed signal comprises a first mix having a first set of individual channels for a standardized loudspeaker setup having the plurality of at least two different loudspeaker locations, wherein the second mixed signal comprises a second mix having a second set of individual channels for the standardized loudspeaker setup having the plurality of at least two different loudspeaker locations, and wherein the steps of generating comprises placing an individual loudspeaker system to each loudspeaker location of the plurality of at least two different loudspeaker locations of the standardized loudspeaker setup, and wherein each individual loudspeaker system placed at the loudspeaker location of the plurality of at least two different loudspeaker locations of the standardized loudspeaker setup comprises the first loudspeaker arrangement and the second loudspeaker arrangement, and wherein each individual loudspeaker system placed at the loudspeaker location of the plurality of at least two different loudspeaker locations of the standardized loudspeaker setup is configured for rendering an individual channel from the first set of individual channels using the first loudspeaker arrangement of the individual loudspeaker system and for rendering a corresponding individual channel from the second set of individual channels using the second loudspeaker arrangement of the individual loudspeaker system.
5. The method of claim 4, wherein the first loudspeaker arrangement comprises one or more loudspeakers comprising a directed sphere wave emission characteristic or a cylinder wave emission characteristic, and wherein the second loudspeaker arrangement comprises one or more loudspeakers comprising an omnidirectional emission characteristic or an emission characteristic being close to the omnidirectional characteristic within a tolerance of 30%.
6. The method of claim 4, wherein said generating of the second sound signal comprises convoluting a signal for a loudspeaker of the second loudspeaker arrangement by an effect signal, the effect signal comprising an impulse response of an intended audio effect.
7. An apparatus of capturing an audio scene comprising a plurality of sound sources, comprising: a first acquisition device configured for acquiring first directivity sound from the plurality of sound sources of the audio scene, the first directivity sound comprising a first directivity to achieve a first acquisition signal, the first acquisition signal comprising a high directivity sound portion from the plurality of sound sources of the audio scene; a second acquisition device configured for acquiring second directivity sound from the plurality of sound sources of the audio scene, the second directivity sound comprising a second directivity to achieve a second acquisition signal, wherein the first directivity is higher than the second directivity, the second acquisition signal comprising a low directivity sound portion from the same plurality of the sound sources of the audio scene, wherein the first acquisition device and the second acquisition device are configured to operate simultaneously, and wherein the first acquisition signal and the second acquisition signal together represent the audio scene comprising the plurality of the sound sources; and a storage configured for separately storing the first acquisition signal and the second acquisition signal; or a transmitter for separately transmitting the first acquisition signal and the second acquisition signal to a loudspeaker setup, wherein the first acquisition device comprises a first set of microphones placed between places for the plurality of the sound sources of the audio scene and places for listeners to the audio scene comprising the plurality of the sound sources or a first set of directed microphones directed so that a maximum sensitivity of the first set of directed microphones is directed to the audio scene comprising the plurality of the sound sources, where microphone signals from the first set are the first acquisition signal; wherein the second acquisition device comprises a second set of microphones placed lateral to the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources or above the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources, where microphone signals from the second set are the second acquisition signal, and wherein the first acquisition signal does not have any contribution from the microphone signals from the second set, and wherein the second acquisition signal does not have any contribution from the microphone signals from the first set.
8. An apparatus for rendering an audio scene, comprising: an acquisition device configured for providing a first mixed signal related to first directivity sound comprising the first directivity and configured for providing a second mixed signal related to second directivity sound comprising the second directivity, wherein the second directivity is lower than the first directivity; and a generator configured for generating a first sound signal from the first mixed signal using a first loudspeaker arrangement comprising a first loudspeaker directivity and configured for simultaneously generating a second sound signal from the second mixed signal by a second loudspeaker arrangement comprising a second loudspeaker directivity, wherein the second loudspeaker directivity is lower than the first loudspeaker directivity, wherein the first mixed signal comprises a mix having a first set of individual channels for a standardized loudspeaker setup having a plurality of at least two different loudspeaker locations, wherein the second mixed signal comprises a mix having a second set of individual channels for the standardized loudspeaker setup having the plurality of at least two different loudspeaker locations, and wherein the generator comprises, for each loudspeaker location of the plurality of at least two different loudspeaker locations, an individual loudspeaker system placed at each loudspeaker location of at least two different loudspeaker locations of the standardized loudspeaker setup, wherein each individual loudspeaker system placed at a loudspeaker location of the plurality of at least two different loudspeaker locations of the standardized loudspeaker setup comprises the first loudspeaker arrangement and the second loudspeaker arrangement, and wherein each individual loudspeaker system placed at a loudspeaker location of the plurality of at least two different loudspeaker locations of the standardized loudspeaker setup is configured for rendering an individual channel from the first set of individual channels using the first loudspeaker arrangement of the individual loudspeaker system and for rendering a corresponding channel from the second set of individual channels using the second loudspeaker arrangement of the individual loudspeaker system.
9. A non-transitory storage medium having stored thereon a computer program for performing, when running on a computer, the method of capturing an audio scene of claim 1.
10. A non-transitory storage medium having stored thereon a computer program for performing, when running on a computer, the method of rendering an audio scene of claim 4.
11. A method of capturing an audio scene comprising a plurality of sound sources, comprising: acquiring first directivity sound from the plurality of sound sources of the audio scene, the first directivity sound comprising a first directivity to achieve a first acquisition signal comprising a first group of individual channels; acquiring second directivity sound from the plurality of sound sources of the audio scene, the second directivity sound comprising a second directivity to achieve a second acquisition signal comprising a second group of individual channels, wherein the first directivity is higher than the second directivity, wherein the steps of acquiring the first directivity sound and the second directivity sound are performed simultaneously, and wherein the first acquisition signal and the second acquisition signal together represent the audio scene comprising the plurality of the sound sources; mixing the first group of individual channels in the first acquisition signal to achieve a first mixed signal, and mixing the second group of individual channels in the second acquisition signal to achieve a second mixed signal, wherein the first group of individual channels and the second group of individual channels are not mixed with each other; and separately storing the first mixed signal and the second mixed signal, or transmitting the first mixed signal and the second mixed signal to a loudspeaker setup, wherein the step of acquiring the first directivity sound having the first directivity comprises placing a first set of microphones between places for the plurality of the sound sources of the audio scene and places for listeners to the audio scene comprising the plurality of the sound sources or directing a first set of directed microphones so that a maximum sensitivity of the first set of directed microphones is directed to the audio scene comprising the plurality of the sound sources and acquiring microphone signals from the first set as the first acquisition signal; and wherein the step of acquiring the second directivity sound having a second directivity comprises placing a second set of microphones lateral to the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources or above the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources, where microphone signals from the second set are the second acquisition signal, and wherein the first acquisition signal does not have any contribution from the microphone signals from the second set, and wherein the second acquisition signal does not have any contribution from the microphone signals from the first set.
12. The method in accordance with claim 11, wherein the mixing the first group of individual channels is configured to generate the first mixed signal comprising a first set of mixed channels, and wherein the mixing the second group of individual channels is configured to generate the second mixed signal comprising a second set of mixed channels.
13. The method of claim 11, wherein the first mixed signal comprising the first set of mixed channels is in a 7.X format, a 5.X format or a stereo format, wherein X is an integer greater than or equal to zero, wherein the second mixed signal comprising the second set of mixed channels is in a 7.X format, a 5.X format or a stereo format, wherein X is the integer greater than or equal to zero, and wherein the audio scene is represented by the first mixed signal comprising the first directivity in a corresponding format, and by the second mixed signal comprising the second directivity in the corresponding format.
14. The method in accordance with claim 12, further comprising: rendering the first mixed signal using a first loudspeaker arrangement comprising a first directivity and simultaneously rendering the second mixed signal using a second loudspeaker arrangement comprising a second directivity, wherein the rendering comprises placing an individual loudspeaker system to each loudspeaker location of a plurality of at least two different loudspeaker locations, and wherein each individual loudspeaker system placed at a loudspeaker location of the plurality of at least two different loudspeaker locations comprises the first loudspeaker arrangement and the second loudspeaker arrangement, and wherein each individual loudspeaker system placed at a loudspeaker location of the plurality of at least two different loudspeaker locations is configured for rendering a channel from the first set of mixed channels using the first loudspeaker arrangement of the individual loudspeaker system and for rendering a corresponding channel from the second set of mixed channels using the second loudspeaker arrangement of the individual loudspeaker system.
15. A method of capturing an audio scene comprising a plurality of sound sources and rendering a captured audio scene, comprising: acquiring first directivity sound from the plurality of the sound sources of the audio scene, the first directivity sound comprising a first directivity to achieve a first acquisition signal comprising a first group of individual channels; acquiring second directivity sound from the plurality of the sound sources of the audio scene, the second directivity sound comprising a second directivity to achieve a second acquisition signal comprising a second group of individual channels, wherein the first directivity is higher than the second directivity, wherein the steps of acquiring the first directivity sound and acquiring the second directivity sound are performed simultaneously, and wherein the first acquisition signal and the second acquisition signal together represent the audio scene comprising the plurality of the sound sources; mixing the first group of individual channels in the first acquisition signal to achieve a first mixed signal, mixing the second group of individual channels in the second acquisition signal to achieve a second mixed signal, wherein the first group of individual channels and the second group of individual channels are not mixed with each other, transmitting the first mixed signal and the second mixed signal to a loudspeaker setup, and rendering the first mixed signal using a first loudspeaker arrangement comprising a first directivity and simultaneously rendering the second mixed signal using a second loudspeaker arrangement comprising a second directivity, the first loudspeaker arrangement being separate from the second loudspeaker arrangement, and wherein the first mixed signal is not rendered with the second loudspeaker arrangement and the second mixed signal is not rendered with the first loudspeaker arrangement; or transmitting the first acquisition signal and the second acquisition signal to a loudspeaker setup, and rendering the first acquisition signal using a first loudspeaker arrangement comprising a first directivity and simultaneously rendering the second acquisition signal using a second loudspeaker arrangement comprising a second directivity, the first loudspeaker arrangement being separate from the second loudspeaker arrangement, and wherein the first acquisition signal is not rendered with the second loudspeaker arrangement and the second acquisition signal is not rendered with the first loudspeaker arrangement, wherein the second loudspeaker directivity is lower than the first loudspeaker directivity, wherein the step of acquiring the first directivity sound having the first directivity comprises placing a first set of microphones between places for the plurality of the sound sources of the audio scene and places for listeners to the audio scene comprising the plurality of the sound sources or directing a first set of directed microphones so that a maximum sensitivity of the first set of directed microphones is directed to the audio scene comprising the plurality of the sound sources and acquiring microphone signals from the first set as the first acquisition signal; and wherein the step of acquiring the second directivity sound having a second directivity comprises placing a second set of microphones lateral to the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources or above the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources, where microphone signals from the second set are the second acquisition signal, and wherein the first acquisition signal does not have any contribution from the microphone signals from the second set, and wherein the second acquisition signal does not have any contribution from the microphone signals from the first set.
16. An apparatus of capturing an audio scene comprising a plurality of sound sources, comprising: a first acquisition device configured for acquiring first directivity sound from the plurality of the sound sources of the audio scene, the first directivity sound comprising a first directivity to achieve a first acquisition signal comprising a first group of individual channels; a second acquisition device configured for acquiring second directivity sound from the plurality of the sound sources of the audio scene, the second directivity sound comprising a second directivity to achieve a second acquisition signal comprising a second group of individual channels, wherein the first directivity is higher than the second directivity, wherein the acquisition devices are configured to operate simultaneously, and wherein the first acquisition signal and the second acquisition signal together represent the audio scene comprising the plurality of the sound sources; a mixer configured for mixing the first group of individual channels in the first acquisition signal to achieve a first mixed signal, and configured for mixing the second group of individual channels in the second acquisition signal to achieve a second mixed signal, wherein the first group of individual channels and the second group of individual channels are not mixed with each other; and a storage configured for separately storing the first mixed signal and the second mixed signal; or a transmitter configured for separately transmitting the first mixed signal and the second mixed signal to a loudspeaker setup, wherein the first acquisition device comprises a first set of microphones placed between places for the plurality of the sound sources of the audio scene and places for listeners to the audio scene comprising the plurality of the sound sources or a first set of directed microphones directed so that a maximum sensitivity of the first set of directed microphones is directed to the audio scene comprising the plurality of the sound sources, where microphone signals from the first set of microphones are the first acquisition signal; and wherein the second acquisition device comprises a second set of microphones placed lateral to the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources or above the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources, where microphone signals from the second set of microphones are the second acquisition signal, and wherein the first acquisition signal does not have any contribution from the microphone signals from the second set, and wherein the second acquisition signal does not have any contribution from the microphone signals from the first set.
17. An apparatus of capturing an audio scene comprising a plurality of sound sources and rendering a captured audio scene, comprising: a first acquisition device configured for acquiring first directivity sound from the plurality of the sound sources of the audio scene, the first directivity sound comprising a first directivity to achieve a first acquisition signal comprising a first group of individual channels; a second acquisition device configured for acquiring second directivity sound from the plurality of the sound sources of the audio scene, the second directivity sound comprising a second directivity to achieve a second acquisition signal comprising a second group of individual channels, wherein the first directivity is higher than the second directivity, wherein the acquisition devices are configured to operate simultaneously, and wherein the first acquisition signal and the second acquisition signal together represent the audio scene comprising the plurality of the sound sources; a mixer configured for mixing the first group of individual channels in the first acquisition signal to achieve a first mixed signal, and configured for mixing the second group of individual channels in the second acquisition signal to achieve a second mixed signal, wherein the first group of individual channels and the second group of individual channels are not mixed with each other; a transmitter configured for separately transmitting the first mixed signal and the second mixed signal to a loudspeaker setup; and a renderer configured for rendering the first mixed signal using a first loudspeaker arrangement comprising a first directivity and simultaneously rendering the second mixed signal using a second loudspeaker arrangement comprising a second directivity, the first loudspeaker arrangement being separate from the second loudspeaker arrangement, and wherein the first mixed signal is not rendered with the second loudspeaker arrangement and the second mixed signal is not rendered with the first loudspeaker arrangement, or a transmitter configured for separately transmitting the first acquisition signal and the second acquisition signal to a loudspeaker setup; and a renderer configured for rendering the first acquisition signal using a first loudspeaker arrangement comprising a first directivity and configured for simultaneously rendering the second acquisition signal using a second loudspeaker arrangement comprising a second directivity, the first loudspeaker arrangement being separate from the second loudspeaker arrangement, and wherein the first acquisition signal is not rendered with the second loudspeaker arrangement and the second acquisition signal is not rendered with the first loudspeaker arrangement, wherein the second loudspeaker directivity is lower than the first loudspeaker directivity, wherein the first acquisition device comprises a first set of microphones placed between places for the plurality of the sound sources of the audio scene and places for listeners to the audio scene comprising the plurality of the sound sources or a first set of directed microphones directed so that a maximum sensitivity of the first set of directed microphones is directed to the audio scene comprising the plurality of the sound sources, where microphone signals from the first set are the first acquisition signal; and wherein the second acquisition device comprises a second set of microphones placed lateral to the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources or above the places for the plurality of the sound sources of the audio scene comprising the plurality of the sound sources, where microphone signals from the second set are the second acquisition signal, and wherein the first acquisition signal does not have any contribution from the microphone signals from the second set, and wherein the second acquisition signal does not have any contribution from the microphone signals from the first set.
18. A non-transitory storage medium having stored thereon a computer program for performing, when running on a computer, the method of capturing an audio scene of claim 11.
19. A non-transitory storage medium having stored thereon a computer program for performing, when running on a computer, the method of capturing an audio scene and rendering a captured audio scene of claim 15.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Embodiments of the present invention will be detailed subsequently referring to the appended drawings, in which:
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DETAILED DESCRIPTION OF THE INVENTION
(15)
(16) In an embodiment, the step of acquiring the sound having a first directivity comprises placing microphones 100 illustrated in
(17) Furthermore, the step 202 of
(18)
(19) As indicated in
(20) The sound acquisition concept illustrated in
(21) When an orchestra is considered, it has been found that the sound energy which is emitted directly in the front direction to the listener is composed mainly of instruments having a high directivity such as trumpets or trombones and, additionally, comes from the singers or vocalists. This high Q sound portion is detected by microphones 100 of
(22) Instruments having a high directivity but which do not directly emit sound in the front direction such as a tuba, different horns or wings and several wood wind instruments and, additionally, instruments having a low directivity such as string instruments, percussion, gong or triangle generate a room-like or less directed sound emission. This low Q sound portion is detected with a microphone set placed lateral and/or above the instruments or with respect to the sound scene. If microphones having a certain directivity are used, it is advantageous that these microphones are directed into the direction of the individual sound sources such as tuba, horns, wood wind instruments, strings, percussion, gong, triangle.
(23) These individual high Q and low Q microphone signals, i.e., the first and second acquisition signals are independently recorded from each other and further processed such as mixed, stored, transmitted or in other ways manipulated. Hence, separate high and low Q mixtures can be mixed to obtain the first and second mixed signals and these mixed signals can be stored within the storage 108 or can be rendered via separate high and low Q speakers.
(24) Dual Q loudspeaker systems illustrated in
(25) Furthermore, as indicated at 115 in
(26) Advantageously, the dual Q technology is combined with the icon technology which is described in the context of
(27) Subsequently,
(28) Furthermore, instead of or in addition to placing the microphones 102 above or lateral to the sound scene and placing the microphones 100 in front of the sound scene, microphones can also be placed selectively in a corresponding proximity to the corresponding instruments.
(29) When the audio scene, for example, comprises an orchestra having a first set of instruments emitting with a higher directivity and a second set of instruments emitting sound with a lower directivity, then the step of acquiring comprises placing the first set of microphones closer to the instruments of the first set of instruments than to the instruments of the second set of instruments to obtain the first acquisition signal and placing the second set of microphones closer to the instruments of the second set of instruments, i.e., the low directivity emitting instruments, than to the first set of instruments to obtain the second acquisition signal.
(30) Depending on the implementation, the directivity as defined by a directivity factor related to a sound source is the ratio of radiated sound intensity at the remote point on the principle axis of a sound source to the average intensity of the sound transmitted through a sphere passing through the remote point and concentric with the sound source. Advantageously, the frequency is stated so that the directivity factor is obtained for individual subbands.
(31) Regarding a sound acquisition by microphones, the directivity factor is the ratio of the square of the voltage produced by sound waves arriving parallel to the principle axis of a microphone or other receiving transducer to the mean square of the voltage that would be produced if sound waves having the same frequency and mean square pressure where arriving simultaneously from all directions with random phase. Advantageously, the frequency is stated in order to have a directivity factor for each individual subband.
(32) Regarding sound emitters such as speakers, the directivity factor is the ratio of radiated sound intensity at the remote point on the principle axis of a loudspeaker or other transducer to the average intensity of the sound transmitted through a sphere passing through the remote point and concentric with the transducer. Advantageously, the frequency is given as well in this case.
(33) However, other definitions exist for the directivity factor as well which all have the same characteristic but result in different quantitative results. For example, for a sound emitter, the directivity factor is a number indicating the factor by which the radiated power would have to be increased if the directed emitter were replaced by an isotopic radiator assuming the sane field intensity for the actual sound source and the isotropic radiator.
(34) For the receiving case, i.e., for a microphone, the directivity factor is a number indicating the factor by which the input power of the receiver/microphone for the direction of maximum reception exceeds the mean power obtained by averaging the power received from all directions of reception if the field intensity at the microphone location is equal for any direction of wave incidence.
(35) The directivity factor is a quantitative characterization of the capacity of a sound source to concentrate the radiated energy in a given direction or the capacity of a microphone to select signals incident from a given direction.
(36) When the measure of the directivity factor is from 0 to 1, then the directivity factor related to the first acquisition signal is advantageously greater than 0.6 and the directivity factor related to the second acquisition is advantageously lower than 0.4. Stated differently, it is advantageous to place the two different sets of microphones so that the values of 0.6 for the first acquisition signal and 0.4 for the second acquisition signal is obtained. Naturally, it will practically not be possible to have a first acquisition signal only having directed sound and not having any omnidirectional sound. On the other hand, it will not be possible to have a second acquisition signal only having omnidirectionally emitted sound and not having directionally emitted sound. However, the microphones are manufactured and placed in such a way that the directionally emitted sound dominates the omnidirectionally emitted sound in the first microphone signal and that the omnidirectionally emitted sound dominates over the directionally emitted sound in the second acquisition signal.
(37) A method of rendering an audio scene comprises a step of providing a first acquisition signal related to sound having a first directivity or providing a first mixed signal related to sound having the first directivity. The method of rendering additionally comprises providing a second acquisition signal related to sound having a second directivity or providing a second mixed signal related to sound having a second directivity, where the first directivity is higher than the second directivity. The steps of providing can be actually implemented by receiving, in the sound rendering portion of
(38) Furthermore, the method of rendering comprises a step of generating (210, 212) a sound signal from the first acquisition signal or the first mixed signal and the step of generating a second sound signal from the second acquisition signal or the second mixed signal. For generating the first sound signal a directional speaker arrangement 118 is used, and for generating the second signal an omnidirectional speaker arrangement 120 is used. Advantageously, the directivity of the directional speaker arrangement is higher than the directivity of the omnidirectional speaker arrangement 120, although it is clear that an ideal omnidirectional emission characteristic can almost not be generated by existing loudspeaker systems, although the loudspeaker of
(39) Advantageously, the emission characteristic of the omnidirectional speakers is close to the ideal omnidirectional characteristic within a tolerance of 30%.
(40) Subsequently, reference is made to
(41) For example, brass instruments are instruments with a mainly translatory sound generation. The human voice generates a translatorial and a rotational portion of the air molecules. For the transmission of the translation, existing microphones and speakers with piston-like operating membranes and a back enclosure are available.
(42) The rotation is generated mainly by playing bow instruments, guitar, a gong or a piano due to the acoustic short-circuit of the corresponding instrument. The acoustic short-circuit is, for example, performed via the F-holes of a violin, the sound hole for the guitar or between the upper and lower surface of the sounding board at a grand or normal piano or by the front and back phase of a gong. When generating a human voice, the rotation is excited between mouth and nose. The rotation movement is typically limited to the medium sound frequencies and can be advantageously acquired by microphones having a figure of eight characteristic, since these microphones additionally have an acoustic short-circuit. The reproduction is realized by mid-frequency speakers with freely vibratable membranes without having a backside enclosure.
(43) The vibration is generated by violins or is strongly generated by xylophones, cymbals and triangles. The vibrations of the atoms within a molecule is generation up to the ultrasound region above 60 kHz and even up to 100 kHz.
(44) Although this frequency range is typically not perceivable by the human hearing mechanism, nevertheless level and frequency-dependent demodulations effects and other effects take place, which are then made perceivable, since they actually occur within the hearing range extending between 20 Hz and 20 kHz. The authentic transmission of vibration is available by extending the frequency range above the hearing limit at about 20 kHz up to more than 60 or even 100 kHz.
(45) The detection of the directional sound portion for a correct location of sound sources involves a directional microphoning and speakers with a high emission quality factor or directivity in order to only put sound to the ears of the listeners as far as possible. For the directional sound, a separate mixing is generated and reproduced via separate speakers.
(46) The detection of the room-like energy is realized by a microphone setup placed above or lateral with respect to the sound sources. For the transmission of the room-like portion, a separate mixing is generated and reproduced by speakers having a low emission quality factor (sphere emitters) in a separate manner.
(47) Subsequently, an advantageous loudspeaker is described with respect to
(48) Furthermore, the carrier 312 comprises a tip portion having a cross-sectional area which is less than 20% of a cross-sectional area of the base portion, where the speaker arrangement 314 is fixed to the tip portion. Advantageously, as illustrated in
(49) The speaker arrangement 314 has a sphere-like carrier structure 316, which is also illustrated in
(50) Advantageously, the speaker arrangement comprises at least six individual speakers and particularly even twelve individual speakers arranged in twelve different directions, where, in this embodiment, the speaker arrangement 314 comprises a pentagonal dodekaeder (e.g. body with 12 equally distributed surfaces) having twelve individual areas, wherein each individual area is provided with an individual speaker membrane. Importantly, the loudspeaker arrangement 314 does not comprise a loudspeaker enclosure and the individual speakers are held by the supporting structure 316 so that the membranes of the individual speakers are freely suspended.
(51) Furthermore, as illustrated in
(52) Alternatively, however, the loudspeaker in
(53) The enclosure furthermore comprises a further speaker 604 which is suspended at an upper portion of the enclosure and which has a freely suspended membrane. This speaker is a low/mid speaker for a low/mid frequency range between 80 and 300 Hz and advantageously between 100 and 300 Hz. This additional speaker is advantageous, sincedue to the freely suspended membranethe speaker generates rotation stimulation/energy in the low/mid frequency range. This rotation enhances the rotation generated by the speakers 314 at low/mid frequencies. This speaker 604 receives the low/mid frequency portion of the signal provided to the speakers at 314, e.g., the second acquisition signal or the second mixed signal.
(54) In an advantageous embodiment with a single subwoofer, the subwoofer is a twelve inch subwoofer in the closed longitudinal enclosure 300 and the speaker arrangement 314 is a pentagon dodekaeder medium/high speaker arrangement with freely vibratable medium frequency membranes.
(55) Additionally, a method of manufacturing a loudspeaker comprises the production and/or provision of the enclosure, the carrier portion and the speaker arrangement, where the carrier portion is placed on top of the longitudinal enclosure and the speaker arrangement with the individual speakers is placed on top of the carrier portion or alternatively the speaker arrangement without the individual speakers is placed on top of the carrier portion and then the individual speakers are mounted.
(56) Subsequently, reference is made to
(57) The microphone comprises a first electret microphone portion 801 having a first free space and a second electret portion 802 having a second free space. The first and the second microphone portions 801, 802 are arranged in a back-to-back arrangement. Furthermore, a vent channel 804 is provided for venting the first free space and/or the second free space. Furthermore, first contacts 806a, 806b for deriving an electrical signal 806c and second contacts 808a and 806b for deriving a second electrical signal 808b are arranged at the first microphone portion 801, and the second microphone portion 802, respectively. Hence,
(58)
(59) The second electret microphone portion 802 is advantageously constructed in the same manner and comprises, from bottom to top, a metallization 820, a foil 821, a spacer 822 defining a second vented free space 823. On the spacer 822 an electret foil 824 is placed and above the electret foil 824 a counter electrode 826 is placed which forms the back plate of the second microphone portion. Hence, elements 820 to 826 represent the second electret microphone portion 802 of the
(60) Advantageously, the first and the second microphone portions have a plurality of vertical vent portions 804b, 804c, as illustrated in
(61) Advantageously, the microphone in accordance with the present invention is a back-electret double-microphone with a symmetrical construction. The metalized foils 811, 821 are moved or excited by the kinetic energy of the air molecules (sound) and therefore the capacity of the capacitor consisting of the back electrode 816, 826 and the metallization 810, 820 is changed. Due to the persistent charge on the electret foils 814, 824, a voltage U.sub.1, U.sub.2 is generated due to the equation Q=CU, which means that U is equal to Q/C. The voltage U.sub.1 is proportional to the movement of the electrode 810, 811, and the voltage U.sub.2 is proportional to the movement of the electrode 820, 821. Two individual electret microphones are arranged in a back-to-back arrangement. The vertical vent portions 804b, 804c are useful in order to avoid a back-like closure of the free spaces 813, 823. In order to maintain this functionality additionally when the microphones are arranged in the back-to-back arrangement, the horizontal vent portions 804a are provided which communicate with the vertical vent portions 804b, 804c. Hence, even in the back-to-back arrangement, a closure of the vented free spaces 813, 823 is avoided.
(62)
(63) Naturally, an actually provided signal combiner does not necessarily have to be the controllability feature. Instead, the in-phase, out-of-phase or weighted addition functionality of the combiner can be correspondingly hardwired so that each microphone has a certain output signal characteristic with the combined C output signal, but this microphone cannot be configured. However, when the controllable combiner has the switching functionality illustrated in
(64) Advantageously, the inventive electret microphone is miniaturized and only has dimensions as are set forth in
(65) Furthermore, in order to fully detect the vibration energy, the icon microphone should have an audio bandwidth of 60 kHz and advantageously up to 100 kHz. To this end, the foils 811, 821 have to be attached to the spacer in a correspondingly stiff manner. The microphone illustrated in
(66) Although some aspects have been described in the context of an apparatus, it is clear that these aspects also represent a description of the corresponding method, where a block or device corresponds to a method step or a feature of a method step. Analogously, aspects described in the context of a method step also represent a description of a corresponding block or item or feature of a corresponding apparatus.
(67) Depending on certain implementation requirements, embodiments of the invention can be implemented in hardware or in software. The implementation can be performed using a digital storage medium, for example a floppy disk, a DVD, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, having electronically readable control signals stored thereon, which cooperate (or are capable of cooperating) with a programmable computer system such that the respective method is performed.
(68) Some embodiments according to the invention comprise a non-transitory data carrier having electronically readable control signals, which are capable of cooperating with a programmable computer system, such that one of the methods described herein is performed or having stored thereon the first or second acquisition signals or first or second mixed signals.
(69) Generally, embodiments of the present invention can be implemented as a computer program product with a program code, the program code being operative for performing one of the methods when the computer program product runs on a computer. The program code may for example be stored on a machine readable carrier.
(70) Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier.
(71) In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.
(72) A further embodiment of the inventive methods is, therefore, a data carrier (or a digital storage medium, or a computer-readable medium) comprising, recorded thereon, the computer program for performing one of the methods described herein.
(73) A further embodiment of the inventive method is, therefore, a data stream or a sequence of signals representing the computer program for performing one of the methods described herein. The data stream or the sequence of signals may for example be configured to be transferred via a data communication connection, for example via the Internet.
(74) A further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein.
(75) A further embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.
(76) In some embodiments, a programmable logic device (for example a field programmable gate array) may be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor in order to perform one of the methods described herein. Generally, the methods are advantageously performed by any hardware apparatus.
(77) While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations and equivalents as fall within the true spirit and scope of the present invention.