METHOD, AUDIO PROCESSING SYSTEM AND MEDIA LEGIBLE BY COMPUTER NON TRANSIT CONFIGURED TO STORE THE ME

专利摘要:
The achievements at present are mainly described in the context of a non-transitory computer-readable system, method and media to produce sound with enhanced spatial detectability and a cross-talk simulation. The audio processing system receives a left and right input channel from an audio input signal, and performs audio processing to generate an output audio signal. The system generates the left and right signals spatially enhanced by adjusting the gain of the side subband components and middle subband components of the left and right input channels. The audio processing system generates the left and right cross-talk channels, such as, by applying a filter and time delay to the left and right input channels, and mixing the spatially enhanced channels with the cross-talk channels. In some embodiments, the system includes high / low frequency enhancement channels and pass-through channels derived from the input channels, which can be mixed with the output audio signal.
公开号:BR112018014724B1
申请号:R112018014724-9
申请日:2017-01-12
公开日:2020-11-24
发明作者:Zachary Seldess；James Tracey；Alan Kraemer
申请人:Boomcloud 360, Inc；
IPC主号:

专利说明:

Historic 1. Field of revelation
[0001] The achievements of the present disclosure generally refer to the field of binaural and stereophonic audio signal processing and, more particularly, to optimize audio signals for reproduction in head-mounted speakers, such as stereo headphones . 2. Description of the related technique
[0002] Stereophonic sound reproduction involves encoding and reproducing signals containing spatial properties of a sound field using two or more transducers. Stereophonic sound allows a listener to perceive a spatial sense in the sound field. In a typical stereo sound reproduction system, two "field" speakers positioned at fixed locations in the listening field convert a stereo signal into sound waves. The sound waves from each speaker in the field propagate through space towards both ears of a listener to create an impression of the sound heard from different directions within the sound field.
[0003] Head-mounted speakers, such as ear sources or ear sources inside the ear, typically include a dedicated left speaker to make sound in the left ear, and a dedicated right speaker to make sound in the right ear. Sound waves generated by a head-mounted speaker operate differently from sound waves generated by a speaker in the field, and such differences may be noticeable to the listener. The same stereo input signal can produce different, and sometimes less preferable, listening experiences when produced from head-mounted speakers and when produced from field speakers. summary
[0004] An adaptive mode audio processing system produces two or more output channels for reproduction by creating simulated contralateral cross-talk signals for each of the output channels, and combining these simulated signals with spatially enhanced signals. The audio processing system can enhance the listening experience over head-mounted speakers, and work effectively on a wide variety of content, including music, movies and games. The audio processing system includes flexible configurations (eg, filters, gains and delays) that provide satisfying acoustically dramatic experiences that particularly enhance the spatial sound field experienced by the listener. For example, the audio processing system can provide head-mounted speakers with a sound field comparable to that experienced when listening to stereo content over speakers in the field.
[0005] In some embodiments, the audio processing system receives an input audio signal including a left input channel and a right input channel. Using left and right input channels, the audio processing system generates a spatially enhanced left and right channel, left and right cross-talk channels, low-frequency and high-frequency enhancement channels, medium channels and pass-through channels. The audio processing system mixes the generated channels, such as, when applying different gains to the channels, to generate the left and right output channels. In one aspect, the audio processing system improves the listening experience of the audio input signal when produced to the head-mounted speakers, simulating the contralateral signal components that are characteristic of the sound wave behavior of the speakers. in the field. The simulated contralateral signals represent both the additional delay that would result from the opposite channel speaker, as well as the filtering effect that would result from the listener's head and ear. The filtering effect is provided by a filter function for a head shadow effect for the respective audio channel. As such, the spatial sense of the sound field is improved and the sound field is expanded, resulting in a more enjoyable listening experience for head-mounted speakers.
[0006] Spatially enhanced channels further enhance the spatial sense of the sound field by adjusting the gain of the side subband components and middle subband components of the left and right input channels. The high and low frequency channels respectively reinforce the low and high frequency components of the input channels. The middle and pass-through channels control the contribution of the incoming audio signal (eg, not spatially enhanced) to the output channels.
[0007] Some embodiments include a method for generating the output channels, including: receiving an incoming audio signal comprising a left input channel and a right input channel; generate a spatially enhanced left channel and a spatially enhanced right channel by adjusting the gain of the side subband components and middle subband components of the left and right input channels; generate a left cross-talk channel by filtering and time delay of the left input channel; generate a right cross-talk channel by filtering and time delay of the right input channel; generate a left output channel by mixing the left spatially enhanced channel and the right cross-talk channel; and generate a right output channel by mixing the right spatially enhanced channel and the left cross-talk channel.
[0008] Some achievements include an audio processing system including: a subband spatial enhancer configured to generate a spatially enhanced left channel and a spatially enhanced right channel by gain adjustment of the side subband components and sub components - average band of a left input channel and a right input channel; a cross-talk simulator configured to: generate a left cross-talk channel by filtering and delaying the left input channel; and generating a right cross-talk channel by filtering and time delay of the right input channel; and a mixer configured to: generate a left output channel by mixing the left spatially enhanced channel and the right cross-talk channel; and generate a right output channel by mixing the right spatially enhanced channel and the left cross-talk channel.
[0009] Some achievements may include non-transitory, computer-readable media configured to store the program code, the program code comprising instructions that, when executed by a processor, cause the processor to: receive an incoming audio signal comprising a left input channel and a right input channel; requires a spatially enhanced left channel and a spatially enhanced right channel by adjusting the gain of the side subband components and middle subband components of the left and right input channels; manages a left cross-talk channel by filtering and delaying the left input channel; manages a right cross-talk channel by filtering and time delay of the right input channel; generate a left output channel by mixing the left spatially enhanced channel and the right cross-talk channel; and generate a right output channel by mixing the right spatially enhanced channel and the left cross-talk channel. Brief description of the drawings
[0010] FIG. 1 illustrates a stereo audio reproduction system.
[0011] FIG. 2 illustrates an exemplary audio processing system, according to one embodiment.
[0012] FIG. 3A illustrates a frequency band divider of a subband spatial enhancer, in accordance with one embodiment.
[0013] FIG. 3B illustrates a frequency band enhancer of the subband spatial enhancer, in accordance with one embodiment.
[0014] FIG. 3C illustrates an enhanced band combiner of the subband spatial enhancer, in accordance with one embodiment.
[0015] FIG. 4 illustrates a subband combiner in accordance with one embodiment.
[0016] FIG. 5 illustrates a cross-talk simulator in accordance with an embodiment.
[0017] FIG. 6 illustrates a passage in accordance with an embodiment.
[0018] FIG. 7 illustrates a high / low frequency reinforcer, in accordance with one embodiment.
[0019] FIG. 8 illustrates a mixer, in accordance with one embodiment.
[0020] FIG. 9 illustrates an exemplary method of optimizing an audio signal for head-mounted speakers, in accordance with one embodiment.
[0021] FIG. 10 illustrates a method of generating spatially enhanced channels from an input audio signal, in accordance with one embodiment.
[0022] FIG. 11 illustrates a method of generating cross-talk channels from the audio input signal, in accordance with one embodiment.
[0023] FIG. 12 illustrates a method of generating the left and right-of-way channels and middle channels from the audio input signal, in accordance with one embodiment.
[0024] FIG. 13 illustrates a method of generating the low and high frequency enhancement channels from the audio input signal, in accordance with one embodiment.
[0025] FIGS. 14 through 18 illustrate the examples of the frequency response graphs of the channel signals generated by the audio processing system, in accordance with one embodiment. Detailed Description
[0026] The features and advantages described in the specification are not all inclusive and, in particular, many features of additional advantages will be apparent to one of ordinary skill in the art considering the drawings, specification and claims. In addition, it should be noted that the language used in the specification was mainly selected for readability and instructional purposes, and may not have been selected to outline or circumscribe the inventive object.
[0027] The Figures (FIG.) And the following description refer to the preferred embodiments by way of illustration only. It should be noted that, from the discussion below, the alternative realizations of the structures and methods disclosed herein will be readily recognized as viable alternatives that can be employed without deviating from the principles of the present invention.
[0028] The reference will now be made in detail to various realizations of the present invention (s), examples of which are illustrated in the attached figures. It is noted that at any time similar practicable or similar reference numbers can be used in the figures and may indicate similar or equal functionality. The figures illustrate the achievements for the purposes of illustration only. One skilled in the art will readily recognize from the description below that alternative embodiments of the structures and methods illustrated here can be employed without deviating from the principles described here. Exemplary audio processing system
[0029] With reference to FIG. 1, two field speakers 110A and 110B positioned at fixed locations in a listening field convert a stereo signal into sound waves, which propagate through space towards a listener 120 to create an impression of sound heard from several directions (eg, the imaginary sound source 160) within the sound field.
[0030] Head-mounted speakers, such as ear sources or ear sources inside the ear, include a dedicated 130L left speaker to emit sound in the 125L left ear and a dedicated 130R right speaker to emit sound in the right ear 125R. As such, signal reproduction through head-mounted speakers operates differently from signal reproduction on field speakers 110A and 110B in several ways.
[0031] Unlike head-mounted speakers, for example, speakers 110A and 110B positioned at a distance from the listener, each produces the "transaural" sound waves that are received in both left and right ears 125L, 125R from listener 120. Right ear 125R receives signal component 112L from speaker 110A with a slight delay relative to when left ear 125L receives signal component 118L from speaker 110A. The time delay of the signal component 112L relative to the signal component 118L is caused by a greater distance between the speaker 110A and the right ear 125R as compared to the distance between the speaker 110A and the left ear 125L. Similarly, left ear 125L receives signal component 112R from speaker 110B with slight relative delay as when right ear 125R receives signal component 118R from speaker 110B.
[0032] Head-mounted loudspeakers emit sound waves close to the user's ears, and therefore generate inferior or nonexistent transaural sound wave propagation, and thus, without contralateral components. Each ear of listener 120 receives an ipsilateral sound component from a corresponding speaker, and no contralateral cross-speech sound component from the other speaker. Correspondingly, the listener 120 will perceive a different and typically smaller sound field with speakers mounted on the head.
[0033] FIG. 2 illustrates an example of an audio processing system 200 for processing an audio signal to head-mounted speakers, in accordance with one embodiment. The audio processing system 200 includes a subband spatial enhancer 210, a cross-talk simulator 215, a pass 220, a high / low frequency reinforcer 225, a mixer 230 and a subband combiner 255. The components of the audio processing system 200 can be implanted in electronic circuits. For example, a hardware component may comprise the dedicated circuitry or logic set that is configured (eg, as a special purpose processing, such as a digital signal processor (DSP), programmable field port arrangement (FPGA) or an application specific integrated circuit (ASIC)) to perform certain operations disclosed here.
[0034] System 200 receives an input X audio signal comprising two input channels, a left XL input channel and a right XR input channel. The input audio signal X can be a stereo audio signal with different left and right input channels. Using the input audio signal X, the system generates an output audio signal 0 comprising two output channels 0L, OU. As discussed in greater detail below, the O audio signal is a mix of a spatial enhancement signal, a simulated cross-talk signal, a low / high frequency enhancement signal and / or other processing outputs based on the signal input X audio. When produced to 280L and 280R head-mounted speakers, output audio signal O provides a listening experience comparable to that of larger field speaker systems, such as in terms of size sound field, spatial sound control and tonal characteristics.
[0035] Subband spatial enhancer 210 receives input audio signal X and generates a spatially enhanced signal Y, including a spatially enhanced left channel YL and a spatially enhanced right channel YR. The subband spatial enhancer 210 includes a frequency band divider 240, a frequency band enhancer 245 and an enhanced subband combiner 250. The frequency band divider 240 receives the left input channel XL and the right input channel XR, and divides the left input channel XL into the left subband components EL (1) through EL (n) and the right input channel XR into the right subband components ER (1) through of ER (n), where n is the number of sub-bands (eg, 4). The n subbands define a group of n frequency bands, with each subband corresponding to one of the frequency bands.
[0036] The frequency band enhancer 245 enhances the spatial components of the input X audio signal by changing the intensity ratios between the middle and side subband components of the left subband components EL (1) through EL (n), and change the intensity ratios between the middle and lateral subband components of the right subband components ER (1) to ER (n). For each frequency band, the frequency band enhancer generates the middle and lateral subband components (eg, Em (l) and Es (l), for the frequency band n = l) from the corresponding left subband and right subband components (eg EL (1) and ER (1), apply different gains to middle and side subband components to generate an improved subband component medium and an enhanced side subband component (eg, Ym (l) and Ys (l)), and then converts the middle and side enhanced subband components into the left and right enhanced subband channels (eg, YL (1) and YR (1)). As such, the frequency band enhancer 245 generates the enhanced left subband channels YL (1) through YL (n) and sub- enhanced rights band YR (1) through YR (n), where n is the number of subband components.
[0037] The enhanced subband combiner 250 generates the left spatially enhanced channel YL from the left enhanced subband channels YL (1) through YL (n), and generates the spatially enhanced right channel YR from the channels sub-band enhanced rights YR (1) through YR (n).
[0038] Subband combiner 255 generates a left subband mixing channel EL by combining left subband components EL (1) through EL (n), and generates a right subband mixing channel ER band when combining the right subband components ER (1) to ER (n). The left subband mixing channel EL and the right subband mixing channel ER are used as inputs for the cross-talk simulator 215, the pass 220, and / or the high / low frequency reinforcer 225. In some realizations, the subband band combiner 255 is integrated with one of the subband spatial enhancer 210, cross-talk simulator 215, pass 220 or high / low frequency reinforcer 225. For example, if the band combiner sub-band 255 is part of the cross-talk simulator 215, then the cross-talk simulator 215 can provide the left subband mix channel EL and the right subband mix channel ER at passage 22 0 and / or reinforcer high / low frequency 225.
[0039] In some embodiments, subband combiner 255 is omitted from system 200. For example, the cross-talk simulator 215, pass 220 and / or high / low frequency reinforcer 225 can receive and process channels original XL and XR audio input instead of EL and ER subband mix channels.
[0040] The cross-talk simulator 215 generates a "head shadow effect" from the audio input signal X. The head shadow effect refers to a transformation of a sound wave caused by wave propagation transaural around and through a listener's head, as would be perceived by the listener if the audio input signal X was transmitted from speakers 110A and 110B to each of the listener's left and right ears 125L and 125R 120 as shown in FIG. 1. For example, the cross-talk simulator 215 generates a left cross-talk channel CL from the left channel EL and a right cross-talk channel CR from the right channel ER. The left cross-talk channel CL can be generated by applying an underpass, delay and gain filter to the left subband mixing channel EL. The right CR cross channel can be generated by applying an underpass, delay and gain filter to the right ER subband mixing channel. In some embodiments, low-platform filters or notch filters can be used, instead of underpass filters to generate the left cross-talk channel CL and the right cross-talk channel CR
[0041] Passage 220 generates a medium channel (L + R) by adding the left subband mix channel EL and the right subband mix channel ER. The middle channel represents the audio data that is common for both the left subband mix channel EL and the right subband mix channel ER. The middle channel can be separated into a left middle channel ML and a right middle channel MR. Passage 220 generates a left-hand channel PL and a right-hand channel PR. The pass-through channels represent the original left and right audio input signals XL and XR, or the left subband mix channel EL and the right ER subband mix channel generated from the audio input signals XL and XR by the frequency band divider 245.
[0042] The high / low frequency reinforcer 225 generates the low frequency channels LFL and LFR, and high frequency channels HFL and HFR from the audio input signal X. The high and low frequency channels represent the dependent improvements frequency to the audio input signal X. In some embodiments, the type or quality of frequency-dependent improvements can be defined by the user.
[0043] The mixer 230 combines the output of the subband spatial enhancer 210, the cross-talk simulator 215, the pass 220 and the high / low frequency reinforcer 225 to generate an audio output signal Which includes the signal left exit OL and right exit sign OR. The left output signal OL is supplied to the left speaker 235L and the right output signal OR is supplied to the right speaker 235R.
[0044] The output signal O generated by mixer 230 is a weighted combination of the outputs from the subband spatial enhancer 210, cross-talk simulator 215, pass 220 and high / low frequency reinforcer 225. For example, the left output channel OL includes a combination of the left spatially enhanced channel YL, right CR cross-talk channel (eg, representing the contralateral signal from a right speaker that would be heard by the left ear via transaural sound propagation ), and preferably still include a combination of the left middle channel ML, left passage channel PL, and left high and low frequency channels LFL and HFL. The right output channel OR includes a combination of the right spatially enhanced channel YR, left cross-talk channel CL (eg, representing the contralateral signal from a left speaker that would be heard by the right ear via the propagation of transaural sound), and preferably still includes a combination of the right medium channel MR, right channel PR, and right channels of high and low frequency LFR and HFR. The relative weights of the signal input to the mixer 230 can be controlled by the gains applied to each of the inputs.
[0045] Detailed exemplary achievements of subband spatial enhancer 210, subband band combiner 255, cross-talk simulator 215, pass 220, high / low frequency reinforcer 225 and mixer 230 are shown in FIGS. 3A through 8, and discussed in more detail below.
[0046] FIG. 3A illustrates the frequency band divider 240 of the subband spatial enhancer 210, in accordance with one embodiment. The frequency band divider 240 divided the left input channel XL into left subband components EL (k) and divides the right input channel XR into the right subband components ER (k) to n defined subbands frequency k. The frequency band divider 240 includes an input gain 302 and a crossing network 304. Input gain 302 receives the left input channel XL and the right input channel XR, and applies a predefined gain for each left XL input channel and right XR input channel. In some embodiments, the same gain is applied to each of the left and right XL and XR input channels. In some embodiments, input gain 302 applies a -2 dB gain to input audio signal X. In some embodiments, input gain 302 is separated from frequency band divider 240, or omitted from system 200 so that no gain is applied to the input X audio signal.
[0047] The crossing network 304 receives the input audio signal X from the input gain 302, and divides the input audio signal X into subband signals E (K). The 304 crossing network can use several types of filters arranged in any of several circuit topologies, such as, serial, parallel or derivative, while the resulting outputs form a set of signals for contiguous sub-bands. Exemplary types of filters included in the intersection network 304 may include infinite impulse response (IIR) or finite impulse response (FIR) passband filters, IIR peak and slope filters, Linkwitz-Riley or the like. The filters divide the left input channel XL into the left subband components EL (k) and divide the right input channel XR into the right subband components ER (k) for each frequency subband k. In one approach, a number of passband filters, or any combination of the underpass filter, passband filter and an overpass filter, are employed to approximate combinations of the critical bands of the human ear. A critical band corresponds to the bandwidth within which a second tone is able to mask an existing primary tone. For example, each of the frequency sub-bands can correspond to a group of critical bands of consolidated Bark scale. For example, the crossing network 304 divides the left input channel XL into four components of the left subband EL (1) to EL (4), corresponding to 0 to 300 Hz (corresponding to the Bark 1-3 scale bands) , 300 to 510 Hz (e.g., Bark 4-5 scale bands), 510 to 2700 Hz (e.g., Bark 6-15 scale bands), and 2700 Hz to Nyquist frequency (e.g. , Bark scale 7-24) respectively, and similarly divides the right input channel XR into the right subband components ER (1) through ER (4), for corresponding frequency bands. The process of determining a consolidated set of critical bands includes using a corpus of audio samples from a wide variety of musical genres, and determining from the samples a long-term average energy ratio of the medium to lateral components. about the 24 critical bands of Bark scale. The contiguous frequency bands with similar long-term average ratios are then grouped together to form the set of critical bands. In other deployments, the filters separate the left and right input channels into fewer or more than four sub-bands. The range of the frequency bands can be adjustable. The crossing network 304 produces a pair of left subband components EL (k) and right subband components ER (k), for k = 1 to n, where n is the number of subbands (p. n = 4 in FIG. 3A).
[0048] The crossing network 304 supplies the left subband components EL (1) to EL (n) and right subband components EL (1) to EL (n) to the frequency band enhancer 245 of the enhancer subband spatial 210. As discussed in more detail below, left subband components EL (1) through EL (n) and right subband components EL (1) through EL (n) can also be provided to the cross-talk simulator 215, passage 220 and high / low frequency reinforcer 225.
[0049] FIG. 3B illustrates the frequency band enhancer 245 of the subband spatial enhancer 210, in accordance with one embodiment. The frequency band enhancer 245 generates the spatially enhanced components of the left subband YL (1) to YL (n) and the spatially enhanced components of the right subband YR (1) to YR (n) from the components of the sub - left band EL (1) to EL (n) and right subband components EL (1) to EL (n).
[0050] The frequency band enhancer 245 includes, for each subband k (where k = 1 to n), an L / R to M / S 320 (k) converter, a medium / side processor 330 (k ) and an M / S to L / R 340 (k) converter. Each L / R to M / S 320 (k) converter receives a pair of enhanced subband components EL (k) and ER (k), and converts these inputs into a medium subband component Em (k) and a side subband component Es (k). The middle subband component Em (k) is a non-spatial subband component that corresponds to a correlated portion between the left subband component EL (k) and the right subband component ER (k) consequently, it includes non-spatial information. In some embodiments, the middle subband component Em (k) is computed as a sum of the subband components EL (k) and ER (k). The side subband component Es (k) is a non-spatial subband component that corresponds to an uncorrelated portion between the left subband component EL (k) and the right subband component ER (k ), therefore, includes spatial information. In some embodiments, the side subband component Es (k) is computed as a difference between the left subband component EL (k) and the right subband component ER (k). In one example, the L / R to M / S 320 converter obtains the non-spatial subband component Em (k) and the spatial subband component Es (k) and the frequency subband k accordingly. with the following equations: In (k) = EL (k) + ER (k) Eq. (1) Es (k) = EL (k) - ER (k) Eq. (2)
[0051] For each subband k, a middle / side processor 330 (k) adjusts the component received from side subband Es (k) to generate a special enhanced side subband component Ys (k), and adjusts the component received from the middle subband Em (k) to generate the improved component of the middle subband Ym (k). In one embodiment, the middle / side processor 330 (k) adjusts the middle subband component Em (k) by a corresponding gain coefficient Gm (k), and delays the amplified non-spatial subband component Gm (k) ) * In (k) by a corresponding delay function Dm to generate an improved middle subband component Ym (k). Similarly, the middle / side processor 330 (k) adjusts the component received from the side subband Es (k) by a corresponding gain coefficient Gs (k), and delays the amplified component of the space subband Gs (k) * XS (k) by a corresponding delay function Ds to generate an improved side subband component Ys (k). The gain coefficients and amount of delay can be adjustable. The gain coefficients and the amount of delay can be determined according to the speaker parameters or they can be fixed for an assumed set of parameter values. The middle / side processor 430 (k) of a frequency subband k generates the improved middle subband component Ym (k) and enhanced side subband component Ym (k) according to the following equations: Ym (k) = Gm (k) * Dm (Em (k), k) Eq. (3) Ys (k) = Gs (k) * Ds (Es (k), k) Eq. (4)
[0052] Each medium / lateral processor 330 (k) produces the medium (non-spatial) subband component Ym (k) and the lateral (spatial) subband component Ys (k) to an M / S converter for corresponding L / R 340 (k) of the respective frequency subband k. Examples of the gain and delay coefficients are listed in the following Table 1. Table 1- Exemplary configurations of the middle / side processors.

[0053] In some embodiments, the medium / lateral processor 330 (1) for the subband from 0 to 300 Hz applies a gain of 0.5 dB to the medium subband component Em (l) and a gain of 4.5 dB to the side subband component Es (l). The middle / side processor 330 (2) for the subband from 300 to 510 Hz applies a gain of 0 dB to the middle subband component Em (2) and a gain of 4 dB to the side subband component Es (two). The mid / side processor 330 (3) for the 510 to 2700 Hz subband applies a gain of 0.5 dB to the medium subband component Em (3) and a gain of 4.5 dB to the sub component -Es side band (3). The middle / side processor 330 (4) for the frequency subband from 2700 Hz to Nyquist applies a gain of 0 dB to the middle subband component Em (4) and a gain of 4 dB to the subband component Es side (3).
[0054] Each M / S to L / R 340 (k) converter receives an improved medium subband component Ym (k) and an improved lateral subband component Ys (k), and converts them to a improved left subband component YL (k) and an improved right subband component YR (k). If the L / R to M / S 320 (k) converter generates the middle subband component Em (k) and the lateral subband component Es (k) according to Eq. (1) and Eq (2) above, the M / S to L / R 340 (k) converter generates the improved left subband component YL (k) and improved right subband component YR (k) from the subband of frequency k according to the following equations: YL (k) = (Ym (k) + YS (k)) / 2 Eq. (5) YR (k) = (Ym (k) -Ys (k)) / 2 Eq. (6)
[0055] In some realization, EL (k) and ER (k) in Eq. (1) and Eq. (2) can be exchanged, in which case YL (k) and YR (k) in Eq. (5) and Eq. (6) are also exchanged.
[0056] FIG. 3C illustrates the enhanced subband combiner 250 of the subband spatial enhancer 210, in accordance with one embodiment. The enhanced subband combiner 250 combines the enhanced left subband components YL (1) to YL (n) (from frequency bands k = 1 to n) from the M / S to L / R 340 converters (1) up to 340 (n) to generate the left spatially enhanced audio channel YL, and to combine the right subband enhanced components YR (1) through YL (n) (from frequency bands k = 1 to n) a from the M / S to L / R converters 340 (1) to 340 (n) to generate the right channel of spatially enhanced audio YR. The enhanced subband combiner 250 may include a left sum 352 that combines the improved left subband components YL (k), a right sum 354 that combines the enhanced right subband components YR (k), and a subband gain 34 6 which applies the gains to the left sum 352 and right sum 354. In some embodiments, the subband gain 35 6 applies a gain of 0 dB. In some embodiments, the left sum combines the improved components of the left subband YL (k) and the right sum 354 combines the enhanced components of the right subband YR (k) according to the following equations: YL = ZYL (k) , for k = 1 to n Eq. (7) YR = £ YR (k), for k = 1 to n Eq. (8)
[0057] In some embodiments, the enhanced subband combiner 250 combines the medium subband subcomponent components Ym (k) and the side subband components Ys (k) to generate a combined component of medium subband Ym and a combined component of lateral subband Ys, and then a single conversion from M / S to L / R is applied per channel to generate YL and YR from Ym and Ys. Average / lateral gains are applied per subband, and can be recombined in several ways.
[0058] FIG. 4 illustrates the subband combiner 255 of the audio processing system 200, in accordance with one embodiment. Subband combiner 255 includes a left sum 402 and a right sum 404. Left sum 402 converts the left subband components EL (1) to EL (n) output from frequency band divider 240 into a left EL subband mixing channel. The right sum 404 combines the right subband components ER (1) through ER (n) output from frequency band divider 240 into a right channel of ER subband mixing. The subband combiner 255 provides the left subband mixing channel EL and the right subband mixing channel ER to the cross-talk simulator 215, pass 220 and high / low frequency reinforcer 225. In some embodiments , the original XL and XR audio input channels are provided to the cross-talk simulator 215, pass 220 and high / low frequency reinforcer 225 instead of the left and right subband mixing channels EL and ER. Here, subband combiner 255 can be omitted from system 200. In another example, subband combiner 255 can decode the left subband mix channel EL and the right subband mix channel ER band from frequency band divider 240 on the original XL and XR input channels. In some embodiments, the sub-band combiner 255 is integrated with the cross-talk simulator 215, or some other system component 200.
[0059] FIG. 5 illustrates the cross-talk simulator 215 of the audio processing system 200, in accordance with one embodiment. The cross-talk simulator generates a left cross-talk channel CL and a right cross-talk channel CR from the left subband mixing channel EL and the right subband mixing channel ER. The left cross-talk channel CL and the right cross-talk channel CR, when mixed with the final output signal O, incorporate the simulated transaural sound wave propagation through the listener's head in the output signal O. For example, the channel left cross-talk CL represents a contralateral sound component that can be mixed (eg by mixer 230) with a right ipsilateral sound component (eg, the right spatially enhanced channel YR) to generate the right channel exit OR. The right cross-talk channel CR represents a contralateral sound component that can be mixed with a left ipsilateral sound component (eg, the right spatially enhanced channel YL) to generate the left output channel OL.
[0060] The 215 cross-talk simulator generates the contralateral sound components for output to the 235L and 235R head mounted speakers, thus providing a speaker-like listening experience on the 235L and 235R head mounted speakers. With reference to FIG. 5, the cross-talk simulator 215 includes a head shadow underpass filter 502 and a cross talk delay 504 to process the left subband mixing channel EL, a head shadow underpass filter 506 and a cross talk delay 508 to process the right subband mix channel ER, and a head shadow gain 510 until applying the gains to the output of the cross talk delay 504 and cross talk delay 508. The pass filter lower head shadow 502 receives the left subband mix channel EL and applies a modulation that models the frequency response of the signal after passing through the listener's head. The output of the head shadow underpass filter 502 is provided to the cross speech delay 504, which applies a time delay to the output of the head shadow underpass filter 502. The time delay represents the transaural distance that is crossed by a contralateral sound component relative to an ipsilateral sound component. The frequency response can be generated based on empirical experiments to determine the frequency-dependent characteristics of the sound wave modulation by the listener's head. See, e.g., J. F. Yu, Y. S. Chen, "The Head Shadow Phenomenon Affected by Sound Source: In Vitro Measurement", Applied Mechanics and Materials, Vols. 284-287, pp. 1715-1720, 2013; Areti Andreopoulou, Agnieszka Roginska, Hariharan Mohanraj, "Analysis of the Spectral Variations in Repeated Head-Related Transfer Function Measurements," Proceedings of the 19th International Conference on Auditory Display (ICAD2013). Lodz, Poland. 6-9 July 2013. International Community for Auditory Display, 2013. For example, and with reference to FIG. 1, the contralateral sound component 112L which propagates to the right ear 125R can be derived from the ipsilateral sound component 118L which propagates to the left ear 125L by filtering the ipsilateral sound component 118L with a frequency response that represents the wave modulation of sound from transaural propagation, and a time delay that models the distance that the 112L contralateral sound component travels (relative to the 118R ipsilateral sound component) to reach the 125R right ear. In some embodiments, the cross-talk delay 504 is applied before the head shadow underpass filter 502.
[0061] Similarly to the right subband mixing channel ER, the head shadow underpass filter 506 receives the right subband mixing channel ER and applies a modulation that models the frequency response of the head listener. The output of the head shadow underpass filter 506 is provided to the cross speech delay 508, which applies a time delay to the output of the head shadow underpass filter 504. In some embodiments, the cross speech delay 508 is applied before the 506 head shadow underpass filter.
[0062] The head shadow gain 510 applies a gain to the output of the cross talk delay 504 to generate the left cross talk channel CL, and applies a gain to the output of the cross talk delay 506 to generate the right talk channel CR cross.
[0063] In some embodiments, the head shadow underpass filters 502 and 506 have a cutoff frequency of 2,023 Hz. The cross-talk delays 504 and 508 apply a delay of 0.792 milliseconds. The 510 head shadow gain applies a gain of -14.4 dB.
[0064] FIG. 6 illustrates the passage 220 of the audio processing system 200, in accordance with one embodiment. Passage 220 generates a medium channel (L + R) M and a passage channel P from the audio input signal X. For example, passage 220 generates a left middle channel ML and a right middle channel MR from left subband mixing channel EL and right subband mixing channel ER, and generates a left channel PL passage and a right channel PR passage from the left channel mixing subband EL and right channel of ER subband mixing.
[0065] Passage 220 includes an L + R 602 combiner, an L + R 604 pass gain and an L / R 606 pass gain. The L + R 602 combiner receives the left sub mix channel - EL band and ER subband mix right channel, and add the left EL subband mix channel with the right ER subband mix channel to generate the audio data that is common to both channel left subband mixing EL and the right subband mixing ER channel. The pass gain of L + R 604 adds a gain to the output of the L + R 602 combiner to generate the left middle channel ML and right middle channel MR. The middle channels ML and MR represent the audio data that are common for both the left subband mix channel EL and the right subband mix channel ER. In some embodiments, the left middle channel ML is the same as the right middle channel MR. In another example, the gain of passage of L + R 604 applies different gains to the middle channel to generate a different left middle channel ML and right middle channel MR.
[0066] The L / R 606 pass gain receives the left subband mix channel EL and the right subband mix channel ER, and adds a gain to the left subband mix channel EL to generate the left channel of passage PL, and adds a gain to the right channel of subband mixing ER to generate the right channel of passage PR. In some embodiments, a first gain is applied to the left subband mixing channel EL to generate the left passage channel PL and a second gain is applied to the right ER subband mixing channel to generate the right passage channel PR, where the first and second gains are different. In some achievements, the first and second gains are the same.
[0067] In some embodiments, passage 220 receives and processes the original XL and XR audio input signals. Here, the middle channel M represents the audio data that is common to both the left and right input signal XL and XR, and the pass-through channel P represents the original audio signal X (eg, without sub coding) frequency bands by frequency band divider 240, and recombination by subband band combiner 255 on the left subband mix channel EL and right subband mix channel ER).
[0068] In some embodiments, the L + R 604 pass gain applies a -18 dB gain to the L + R 602 combiner output. The L / R 606 pass gain applies an infinite dB gain to the left subband mixing channel EL and right subband mixing channel ER.
[0069] FIG. 7 illustrates the high / low frequency reinforcer 225 of the audio processing system 200, in accordance with one embodiment. The high / low frequency reinforcer 225 generates the low frequency channels LFL and LFR, and high frequency channels HFL and HFR from the left subband mixing channel EL and the right subband mixing channel ER. High and low frequency channels represent the frequency-dependent improvements to the X audio input signal.
[0070] The high / low frequency reinforcer 225 includes a first low frequency enhancement bandpass filter (LF) 702, a second LF 704 enhancement bandpass filter, an LF 705 gain filter, a high frequency enhancement (HF) 708 pass filter and an HF 710 filter gain. The LF 702 enhancement bandpass filter receives the left subband mix channel EL and the right channel from ER subband mixing, and applies a modulation that attenuates the signal components outside of a band or frequency dispersion, thus allowing the passage of signal components (eg, low frequency) within the frequency band. The LF enhancement bandpass filter 7 04 receives the output from the LF enhancement bandpass filter 704, and applies another modulation that attenuates the signal components outside the frequency band.
[0071] The LF 702 enhancement bandpass filter and LF 704 enhancement bandpass filter provide a cascade resonator for low frequency enhancement. In some embodiments, the LF 702 and 704 enhancement bandpass filters have a center frequency of 58,175 Hz with an adjustable quality factor (Q). The Q factor can be adjusted based on user adjustment or programmatic configuration. For example, a standard adjustment may include a Q factor of 2.5, while a more aggressive adjustment may include a Q factor of 1.3. Resonators are configured to display a response with less damping (Q> 0.5) to improve the temporal envelope of low-frequency content.
[0072] The LF 706 filter gain applies a gain to the LF enhancement bandpass filter output 7 04 to generate the left LF channel LFL and right LF channel LFR. In some embodiments, the LF 706 filter gain applies a 12 dB gain to the LF 704 enhancement bandpass filter output.
[0073] The HF 708 enhancement high pass filter receives the left subband mixing channel EL and the right subband mixing channel ER, and applies a modulation that attenuates signal components with lower frequencies than than a cutoff frequency, thus allowing the passage of signal components with frequencies higher than the cutoff frequency. In some embodiments, the HF 708 enhancement high pass filter is a second order Butterworth high pass filter with a cutoff frequency of 4573 Hz.
[0074] The HF 710 filter gain applies a gain to the HF 704 enhancement high pass filter output to generate the left HF channel HFL and right HF channel HFR. In some embodiments, the HF 710 filter gain applies a 0 dB gain to the HF 708 enhancement high pass filter output.
[0075] FIG. 8 illustrates the mixer 230 of the audio processing system 200, in accordance with one embodiment. Mixer 230 generates output channels OL and OU based on weighted combinations of outputs from subband spatial enhancer 210, cross-talk simulator 215, pass 220 and high / low frequency reinforcer 225. Mixer 230 provides the left output channel OL to the left speaker 235L and the right output signal OR to the right speaker 235R
[0076] The mixer 230 includes a left sum 802, a right sum 804 and an output gain 806. The left sum 802 receives the left spatially enhanced channel YL from the subband spatial enhancer 210, the right speech channel CR crossover from the cross-talk simulator 215, the left middle channel ML and the left passage channel PL from passage 220, and the left high and low frequency channels LFL and HFL from the high / low frequency reinforcer 225, and the left sum 802 combines these channels. Similarly, the right sum 804 receives the left spatially enhanced channel YR from the subband spatial enhancer 210, the left cross-talk channel CL from the cross-talk simulator 215, the right middle channel MR and the right channel of passage PR from passage 220, and the right high and low frequency channels LFR and HFR from the high / low frequency reinforcer 225, and the right sum 804 combines these channels.
[0077] Output gain 806 applies a gain to the output of the left sum 802 to generate the left output channel OL, θ applies a gain to the output of the right sum 804 to generate the right output channel OR. In some embodiments, the output gain 806 applies a gain of 0 dB to the output of the left sum 802 and right sum 804. In some embodiments, the subband gain 356, the head shadow gain 510, the pass gain of L + R 604, pass gain of L / R 606, filter gain of LF 706 and / or filter gain of HF 710 are integrated with mixer 230. Here, mixer 230 controls the relative weighings of the input channel contribution to output channels OL and OU.
[0078] FIG. 9 illustrates a method 900 of optimizing an audio signal for head-mounted speakers, in accordance with one embodiment. The audio processing system 200 can perform the steps in parallel, perform the steps in different orders, or perform different steps.
[0079] System 200 receives 905 an input X audio signal comprising a left XL input channel and a right XR input channel. The audio input signal X can be a stereo signal where the left and right input channels XL and XR are different.
[0080] System 200, like the subband spatial enhancer 210, generates 910 a spatially enhanced left channel YL and a spatially enhanced right channel YR from the gain adjustment of the side subband components and components of middle subband of the left and right XL and XR input channels. The left and right spatially enhanced channels YL and YR improve the spatial sense in the sound field by changing the intensity ratios between the middle and lateral subband components derived from the left and right XL and XR input channels, as discussed in greater detail below with respect to FIG. 10.
[0081] System 200, such as the cross-talk simulator 215, generates 915 a left-hand CL cross-talk channel from the filtering and time delay of the left XL input channel, and a right CR cross-talk channel a from the filtering and time delay of the right XR input channel. The cross-talk channels CL and CR simulate transaural contralateral cross-talk to the left XL input channel and the right XR input channel that would reach the listener if the left XL input channel and the right XR input channel were produced from of the speakers, as shown in FIG. 1. Generating cross-talk channels is discussed in greater detail below with respect to FIG. 11.
[0082] System 200, like passage 220, generates 920 a left channel of passage PL from the left channel of input XL, a right channel of passage PR from the right channel of input XR. System 200, like passage 220, generates 925 left and right ML and MR middle channels from combining the left XL input channel and the right XR input channel. The pass-through channels can be used to control the relative contributions of the raw input channel X to the output channel O, and the middle channels can be used to control the relative contribution of the common audio data of the left input channel XL and channel XR entry right. Generating the middle passage and channels is discussed in more detail below with respect to FIG. 12.
[0083] System 200, such as the high / low frequency reinforcer 225 generates 930 the left and right low frequency channels LFL and LFR to apply a resonator in cascade to the left input channel XL and right input channel XR. The low frequency channels LFL and LFR control the relative enhancement of low frequency audio components from input channel X to output channel O.
[0084] System 200, such as the high / low frequency reinforcer 255 generates 935 left and right high frequency HFL and HFR channels to apply a high pass filter to the left XL input channel and the right XR input channel. The high frequency HFL and HFR channels control the relative enhancement of the high frequency audio components from input channel X to output channel O. Generating the LF and HF channels is discussed in more detail below with respect to FIG. 13.
[0085] System 200, like mixer 230, generates 940 the output channel OL and the output channel OU. The output channel OL can be provided to a left-mounted speaker 235L and the right output channel OU is provided to a right speaker 235R. The output channel OL is generated from a weighted combination of the left spatially enhanced channel YL from the subband spatial enhancer 210, the right cross-talk channel CR from the cross-talk simulator 215, the left middle channel ML and the left channel of passage PL from passage 220, and the left channels of high and low frequency LFL and HFL from the reinforcer of high / low frequency 225. The output channel OU is generated from a weighted combination , the left spatially enhanced channel YR from the subband spatial enhancer 210, the left cross-talk channel CL from the cross-talk simulator 215, the right middle channel MR and the right-hand channel PR from the pass 220, and the right high and low frequency channels LFR and HFR from the high / low frequency reinforcer 225.
[0086] The relative weights of the inputs to the mixer 230 can be controlled by the gain filters on the channel sources as discussed above, such as, the input gain 302, the subband gain 356, the head shadow gain 510 , L + R 604 pass gain, L / R 606 pass gain, LF 706 filter gain and HF 710 filter gain. For example, a gain filter can reduce a signal amplitude of a channel to reduce the contribution of the channel to the output channel O, or increase the signal amplitude to increase the contribution of the channel to the output channel 0. In some embodiments, the signal amplitudes of one or more channels can be set to 0 or substantially 0, resulting in no contribution from one or more channels to output channel O.
[0087] In some embodiments, subband gain 356 applies between a gain of -12 to 6 dB, head shadow gain 510 applies an infinite gain up to 0 dB, filter gain of LF 706 applies a gain of 0 to 20 dB, the filter gain of HF 710 applies a gain of 0 to 20 dB, the pass gain of L / R 606 applies an infinite gain to 0 dB, and the gain of pass L + R 604 applies an infinite gain of up to 0 dB. The relative earnings figures can be adjustable to provide different settings. In some embodiments, the audio processing system uses predefined sets of gain values. For example, the subband gain 35 6 applies the gain of 0 dB, the head shadow gain 510 applies a gain of -14.4 dB, the filter gain of LF 70 6 applies between a gain of 12 dB , the filter gain of HF 710 applies a gain of 0 dB, the pass gain of L / R 606 applies the gain of infinite dB, and the gain of pass of L + R 604 applies a gain of -18 dB.
[0088] As discussed above, the steps in method 900 can be performed in different orders. In one example, steps 910 through 935 are performed in parallel, so that input channels Y, C, M, LF and HF are available to mixer 230 at substantially the same time for combining.
[0089] FIG. 10 illustrates a method 1000 of generating the spatially enhanced channels YL and YR from an input X audio signal, in accordance with one embodiment. Method 1000 can be performed on 910 of method 900, such as by the subband spatial enhancer 210 of system 200.
[0090] Subband spatial enhancer 210, such as the crossing network 304 of frequency band divider 240, separates 1010 input channel XL into subband mix subband channels EL (1 ) to EL (n), and separates the input channel XR into subband mix subband channels ER (1) through ER (n). N is a pre-defined number of subband channels, and in some embodiments, it is four subband channels corresponding to 0 to 300 Hz, 300 to 510 Hz, 510 to 2700 Hz, and 2700 Hz to Nyquist Frequency , respectively. As discussed above, the n sub-band channels bring the critical bands closer to the human ear. The n subband channels are a set of consolidated critical bands determined by using a corpus of audio samples from a wide variety of musical genres, and determining from the samples a long-term average energy ratio of the components medium to lateral over 24 critical bands of Bark scale. The contiguous frequency bands with similar long-term average ratios are then grouped together to form the set of n critical bands.
[0091] The subband spatial enhancer 210, like the L / R to M / S converters 320 (k) of the frequency band enhancer 245, generates 1020 Es (k) spatial subband component and non-spatial subband component Em (k) for each subband k (where k = 1 to n). For example, each L / R to M / S 320 (k) converter receives a pair of subband mixing sub-band components EL (k) and ER (k), and converts these inputs into a component of middle subband Em (k) and a lateral subband component Es (k) according to Eqs. (1) and (2) discussed above. For n = 4, the L / R to M / S converters 320 (1) through 320 (4) generate the spatial subband components Es (l), Es (2), Es (3) and Es (4 ), and non-spatial subband component Em (l), Em (2), Em (3), and Em (4).
[0092] The subband spatial enhancer 210, as well as the middle / side processors 330 (k) of the frequency band enhancer 245, generates 1030 an enhanced Ys spatial subband component (k) and an enhanced component non-spatial subband Ym (k) for each subband k. For example, each of the middle / side processors 330 (k) converts an average subband component Em (k) into an enhanced spatial subband component Ym (k) by applying a Gm gain (k) and a function delay D according to Eq. (3). Each of the middle / side processors 330 (k) converts a side subband component Es (k) into an enhanced spatial subband component Ys (k) by applying a Gs gain (k) and a delay function D according to Eq. (4).
[0093] In some embodiments, the values of the gains Gm (k) and Gs (k) for each subband k are initially determined based on the long-term average energy ratio of sampling the average components to the sides over the sub - band k from a corpus of audio samples, such as from a wide variety of musical genres. In some embodiments, audio samples may include different types of audio content, such as movies, films and games. In another example, sampling can be performed using audio samples known to include the desired spatial properties. These mean energy to lateral ratios are used as a starting point when calculating the gains of Gm and Gs for the middle subband component Ym (k) and the improved side subband component Ys (k). The final sub-band gains are then defined through subjective expert hearing tests on a wide body of audio samples, as described above. In some embodiments, the gains Gm and Gs, and delays Dm and Ds, can be determined according to the speaker parameters or can be fixed to an assumed set of parameter values.
[0094] The subband spatial enhancer 210, like the M / S to L / R converters 340 (k) of the frequency band enhancer 245, generates 1040 a spatially enhanced component of the left subband YL ( k) and a spatially enhanced component of the right subband YR (k) for each subband k. Each M / S to L / R 340 (k) converter receives a medium enhanced component Ym (k) and a lateral enhanced component Ys (k), and converts them to the spatially enhanced component of the left subband YL (k) and spatially improved component of the right subband YR (k), such as, according to Eqs. (5) and (6). Here, the spatially enhanced left subband component YL (k) is generated based on adding the middle enhanced component Ym (k) and the lateral enhanced component Ys (k), and the spatially enhanced right subband component YR (k) (k) is generated based on subtracting the lateral enhanced component Ys (k) from the medium enhanced component Ym (k). For n = 4 sub-bands, the M / S to L / R converters 340 (1) to 340 (4) generate the improved components of the left subband YL (1) to YL (4), and the improved component of right subband YR (1) to YR (4).
[0095] The subband spatial enhancer 210, such as the enhanced subband combiner 250, generates 1050 a spatially enhanced left channel YL by combining the enhanced left subband components YL (1) through YL (n ), and a spatially enhanced right channel YR by combining the enhanced components of the right subband YR (1) through YR (n). The combinations can be performed based on Eqs. 5 and 6 as discussed above. In some embodiments, the enhanced subband combiner 250 may further apply a subband gain to the left spatially enhanced channel YL and left spatially enhanced channel YR that control the contribution of the left spatially enhanced channel YL to the left output channel OL, and the contribution of the spatially enhanced right channel YR to the right output channel OU. In some embodiments, the subband gain is a 0 dB gain to serve as a baseline level, with the other gains discussed here being defined relative to the 0 dB gain. In some embodiments, such as when the 302 input gain is different from the -2 dB gain, the subband gain can be adjusted accordingly (eg, to achieve a desired baseline level for the spatially channel) enhanced left YL and spatially enhanced left YR channel).
[0096] In different embodiments, the steps in method 1000 can be performed in different orders. For example, the enhanced spatial subband components Ys (k) for the subbands k = l to n can be combined to generate Ys, and the enhanced non-spatial subband component Ym (k) for the sub- bands k = l to n can be combined to generate Ym. Ys and Ym can be converted to the spatially enhanced channels YL and YR using the conversion from M / S to L / R.
[0097] FIG. 11 illustrates a method 1100 of generating cross-talk channels from the audio input signal, in accordance with one embodiment. The 1100 method can be performed on 915 of the 900 method. The cross-talk channels CL and CR, which represent the contralateral cross-talk signals, are generated based on applying a filter and a time delay to the ipsilateral input channels XL and XR.
[0098] The subband band combiner 255 of system 200 generates 1110 a left channel of subband mixing EL by combining the subband mixing subband channels EL (1) to EL (n) , and a right subband mix channel ER by combining the subband mix subband channels ER (1) through ER (n). The left subband mix channel EL and the right subband mix channel ER are used as inputs for the cross-talk simulator 215, pass 220 and / or high / low frequency reinforcer 225. In some embodiments, the cross-talk simulator 215, the passage 220 and / or the high / low frequency reinforcer 225 can receive and process the original audio input channels XL and XR instead of the subband mix channels EL and ER. Here, step 1100 is not performed, and subsequent processing steps for method 1100 are performed using the XL and XR audio input channels. In some embodiments, the subband band combiner 255 decodes the left subband channels of subband mix EL (1) through EL (n) on the left input channel XL, and decodes the subband channels mixing rights of subband ER (1) to ER (n) in the right XR input channel.
[0099] The system 200 cross-talk simulator 215 applies 1120 a first underpass filter to the left subband mixing channel EL. The first underpass filter may be the head shadow underpass filter 502 of the cross-talk simulator 215, which applies a modulation that models the frequency response of the signal after passing through the listener's head. As discussed above, the 502 head shadow underpass filter can have a cutoff frequency of 2,023 Hz, where the frequency components of the left subband mixing channel EL that exceed the cutoff frequency are attenuated. Other realizations of the system 200 cross-talk simulator 215 may employ a low-platform filter or notch for the head shadow underpass filter. This filter can have a cutoff / center frequency of 2023 Hz, with a Q between 0.5 and 1.0 and a gain between -6 and - 24 dB.
[00100] The cross-talk simulator 215 applies 1130 a first cross-talk delay to the output of the first underpass filter. For example, the cross delay 504 provides a time delay that models the increased transaural distance (and thus increased travel time) that a contralateral sound component 112L from the left speaker 110A travels relative to the ipsilateral sound component 118R from the right speaker 110B to reach the right ear 125R of the listener 120, as shown in FIG. 1. In some embodiments, the cross delay 504 applies a 0.792 millisecond cross-talk delay to the left filtered EL subband mix channel. In some embodiments, steps 1120 and 1130 are reversed so that the first cross-talk delay is applied before the first underpass filter.
[00101] The cross-talk simulator 215 applies 1140 a second underpass filter to the right ER subband mixing channel. The second underpass filter may be the head shadow underpass filter 506 of the cross-talk simulator 215, which applies a modulation that models the frequency response of the signal after passing through the listener's head. In some embodiments, the 506 head shadow underpass filter may have a cutoff frequency of 2,023 Hz, where the frequency components of the right ER subband mixing channel that exceed the cutoff frequency are attenuated. Other realizations of the system 200 cross-talk simulator 215 may employ a low-platform filter or notch for the head shadow underpass filter. This filter can have a cutoff frequency of 2023 Hz, with a Q between 0.5 and 1.0 and a gain between -6 and -24 dB.
[00102] The cross-talk simulator 215 applies 1150 a second cross-talk delay to the output of the second underpass filter. The second time delay models the increased transaural distance that a contralateral sound component 112R from the right speaker 110B travels relative to the ipsilateral sound component 118L from the left speaker 110B to reach the left ear 125L of the listener 120 , as shown in FIG. 1. In some embodiments, the cross delay 508 applies a delay of 0.792 milliseconds of cross speech to the left filtered channel of the ER subband mix. In some embodiments, steps 1140 and 1150 are reversed so that the second cross-talk delay is applied before the second underpass filter.
[00103] The cross-talk simulator 215 applies 1160 a first gain to the output of the first cross-talk delay to generate a left cross-talk channel CL. The cross-talk simulator 215 applies 1170 a second gain to the output of the second cross-talk delay to generate a right CR cross-talk channel. In some embodiments, the head shadow gain 510 applies a gain of -14.4 dB to generate the left cross-talk channel CL and the right cross-talk channel CR.
[00104] In various embodiments, the steps in method 1100 can be performed in different orders. For example, steps 1120 and 1130 can be performed in parallel with steps 1140 and 1150 until processing the left and right channels in parallel, and generating the left cross-talk channel CL and right cross-talk channel CR in parallel.
[00105] FIG. 12 illustrates a method 1200 of generating the left and right-of-way channels and middle channels from the audio input signal, in accordance with one embodiment. Method 1200 can be performed on 920 and 925 of method 900. The pass-through channel controls the contribution of the spatially unenhanced input channel X to the output channel 0, and the middle channel controls the contribution of the common audio data of the spatially channel not enhanced left input XL and the non-spatially right channel input XR to output channel 0.
[00106] Passage 220 of the audio processing system 200 applies 1210 a gain to the left subband mix channel EL to generate a PL pass channel, and a gain to the right ER subband mix channel to generate a PR pass channel. In some embodiments, the L / R 606 pass gain of pass 220 applies an infinite dB gain to the left subband mix channel EL and the right subband mix channel ER. Here, the pass-through channels PL and PR are fully attenuated and do not contribute to the output signal O. The gain level can be adjusted to control the amount of the spatially unimproved input signal that contributes to the output signal 0.
[00107] Passage 220 combines 1230 the left subband mix channel EL and the right subband mix channel ER to generate a medium channel (L + R). For example, the L + R 602 combiner from passage 22 0 adds the left subband mix channel EL with the right subband mix channel ER to a channel with the audio data that is common to both left subband mix channel EL and the right subband mix channel ER.
[00108] Passage 220 applies a gain to the middle channel to generate an ML left middle channel, and a gain to the middle channel to generate a right MR middle channel. In some embodiments, the pass gain of L + R 604 applies a gain of -18 dB to the output of the L + R 602 combiner to generate the left and right middle channels ML and MR. The gain level can be adjusted to control the amount of the non-spatially enhanced average input signal that contributes to the O output signal. In some embodiments, a single gain is applied to the average channel, and the average channel applied per gain is used for the left and right channels ML and MR.
[00109] In different embodiments, the steps in method 1200 can be performed in different orders. For example, steps 1210 and 1230 can be performed in parallel to generate the through channels and middle channel in parallel.
[00110] FIG. 13 illustrates a 1300 method of generating low and high frequency enhancement channels from the audio input signal, in accordance with one embodiment. The 1300 method can be performed on 930 and 935 of the 900 method. The LF enhancement channels control the contribution of low frequency components from the spatially unenhanced input channel X to the output channel 0. The HF enhancement channels control the contribution of the high frequency components of the spatially not enhanced input channel X to the output channel O.
[00111] The high / low frequency booster 225 of the audio processing system 200 applies 1310 a first bandpass filter to the left subband mixing channel EL and the right subband mixing channel ER, and a second bandpass filter at the exit of the first bandpass filter. For example, the LF 702 enhancement bandpass filter and LF 704 enhancement bandpass filter provide a cascade resonator for low frequency enhancement. The characteristics of the first and second bandpass filters can be adjustable, such as different settings with predefined factor Q and / or center frequency of the bandpass filters. In some embodiments, the center frequency is set to a pre-defined level (eg, 58.175 Hz), and the Q factor is adjustable. In some embodiments, a user can select from a predefined set of settings for the bandpass filters. The cascade bandpass filter system selectively improves the energy in the signal that would typically be handled via a subwoofer in a loudspeaker system in the field, but which is often not sufficiently represented when produced on head-mounted speakers ( ie, ear sources). The fourth-order filter design (ie, two cascading second-order bandpass filters) exhibits a clear time response when excited, adding a "vigor" to key low-frequency elements within the mix, such as kick and bass, while avoiding a general "obscurity" that can occur if you simply increase low-frequency energy over a wider band in the low-frequency spectrum using a second-order, low-platform, or peak-bandpass filter.
[00112] The high / low frequency reinforcer 225 applies a 1320 gain to the output of the second bandpass filter to generate the low frequency channels LFL and LFR. For example, the LF 706 filter gain applies a gain to the LF 704 enhancement bandpass filter output to generate the left LF channel LFL and the right LF channel LFR. The filter gain of LF 706 controls the contribution of the low frequency channels LFL and LFR to the audio output channels OL and OU.
[00113] The high / low frequency reinforcer 225 applies a high pass filter 1330 to the left subband mixing channel EL and the right subband mixing channel ER. For example, the HF 708 enhancement high pass filter applies a modulation that attenuates signal components with lower frequencies than a HF 708 enhancement high pass filter cutoff frequency. As discussed above, the pass filter HF 708 enhancement can be a second order Butterworth filter with a cutoff frequency of 4573 Hz. In some embodiments, the characteristics of the high pass filter are adjustable, such as different cutoff frequency and gain settings are applied to the high pass filter outlet. The general high-frequency amplification achieved through the addition of this high-pass filter serves to accentuate impacting timymic, spectral and temporal information within typical musical signals (eg, high-frequency percussion, such as cymbals, high-frequency elements the responses of the acoustic room, etc.). Furthermore, this enhancement serves to increase the perceived effectiveness of the spatial signal enhancement, while avoiding undue coloring in the low and medium frequency non-spatial signal elements (commonly vocals and bass).
[00114] The high / low frequency reinforcer 225 applies 1340 a gain to the output of the high pass filter to generate the high frequency channels HFL and HFR. The gain level can be adjusted to control the contribution of the HFL and HFR high frequency channels to the 0L and OU audio output channels. In some embodiments, the HF 710 filter gain applies a 0 dB gain to the HF 708 enhancement high pass filter output.
[00115] In different embodiments, the steps in method 1300 can be performed in different orders. For example, steps 1310 and 1330 can be performed in parallel with steps 1330 and 1340 to generate the high and low frequency channels in parallel.
[00116] FIG. 14 illustrates a 1400 frequency graph of the audio channels, in accordance with one embodiment. In graph 1400, the audio processing system 200 operates in a standard setting where the cascade resonators (eg, LF 702 enhancement bandpass filter and LF 7 04 enhancement bandpass filter) of the high / low frequency reinforcer 225 have a center frequency of 58,175 Hz and a Q factor of 2.5. Line 1410 is a frequency response of a white noise X audio input signal on the left XL input channels. Line 1420 is a frequency response from a subband 210 spatial enhancer that generates the spatially enhanced channel Y, considering the same XL white noise input signal. Line 1430 is a frequency response from a cross-talk simulator 215 that generates a cross-talk channel C, considering the same XL white noise input signal. Line 1440 is a frequency response of the high / low frequency reinforcer 225 that generates the high and low frequency channels LF and HF, considering the same XL white noise input signal. The pass gain of L / R 606 is set to -infinity dB in the standard setting, eliminating the contribution of the pass channel P to the output signal O.
[00117] FIG. 15 illustrates a frequency plot 1500 of the audio channels, in accordance with one embodiment. Line 1510 is a frequency response of a white noise X audio input signal on the left XL input channels. As in Figure 1400, the cascade resonators (eg, LF 702 enhancement bandpass filter and LF enhancement bandpass filter 7 04) of the high / low frequency reinforcer 225 operate at the default setting where bandpass filters have a center frequency of 58, 175 Hz and a Q factor of 2.5. Line 1520 is a frequency response from mixer 230 that generates the left output OL channel, considering the same XL white noise input signal. Line 1530 is a frequency response from mixer 230 that generates the left output channel OL, considering a correlated stereo white noise input signal (i.e., left and right signals are identical). Line 1540 is a frequency response from mixer 230 that generates the left OL output channel, considering an uncorrelated white noise input signal (i.e., right channel is an inverted version of the left channel)
[00118] FIG. 16 illustrates a 1600 frequency plot of the channel signals, in accordance with one embodiment. The audio processing system 200 operates in a reinforced setting, where the cascading resonators (eg, LF 702 enhancement bandpass filter and LF 704 enhancement bandpass filter) of the high reinforcer / low frequency 225 has a center frequency of 58.175 Hz and a Q factor of 1.3. Line 1610 is a frequency response of a white noise X audio input signal on the left XL input channels. Line 162 0 is a frequency response of a subband 210 spatial enhancer that generates the spatially enhanced channel. Y, considering the same XL white noise input signal. Line 1630 is a frequency response from a cross-talk simulator 215 that generates the cross-talk channel C, considering the same XL white noise input signal. Line 164 0 is a combined frequency response of the high / low frequency reinforcer 225 and pass 230 in the reinforced setting, considering the same XL white noise input signal.
[00119] FIG. 17 illustrates the individual components of line 1640 above. Line 1710 is a frequency response from the low frequency enhancement above. Line 1720 is a frequency response from the above high frequency filter enhancement. Line 1730 is a frequency response of the pass above 220. Lines 1710, 1720 and 1730 represent the components of the combined filter response of line 1640 shown in FIG. 16 for the audio processing system 200 operating in the enhanced setting.
[00120] FIG. 18 illustrates a 1800 frequency graph of the audio channels, in accordance with one embodiment. The audio processing system 200 operates in the enhanced setting. Line 1810 is a frequency response of a white noise X audio input signal on the left XL input channels. Line 1820 is a frequency response of mixer 230 that generates the left OL output channel, considering the same XL. white noise input signal. Line 1830 is a frequency response graph from mixer 230 that generates the left output OL channel, considering a correlated stereo white noise input signal (i.e., left and right signals are identical). Line 1840 is a frequency response from mixer 230 that generates the left output OL channel, considering an uncorrelated white noise input signal (i.e., right channel is an inverted version of the left channel).
[00121] When reading this revelation, those skilled in the art will still appreciate additional alternative achievements through the principles revealed here. Thus, while the particular realizations and applications have been illustrated and described, it is understood that the realizations revealed are not limited to the precise construction and components disclosed herein. Several modifications, alterations and variations, which will be apparent to those with skill in the technique, can be made in the arrangement, operation and details of the method and mechanism disclosed here without deviating from the scope described here. Any of the steps, operations or processes described here can be performed or implemented with one or more hardware or software modules, alone or in combination with other devices. In one embodiment, a software module is deployed with a computer program product comprising a computer-readable media (eg, non-transitory computer-readable media) containing computer program code, which can be executed by a computer processor to perform all or any of the steps, operations or processes described.

权利要求:
Claims (20)
[0001]
1. Method, characterized by the fact that it comprises the steps of: - receiving an input audio signal (X) comprising a left input channel (XL) and a right input channel (XR); - generate a spatially enhanced left channel (YL) and a spatially enhanced right channel (YR) by adjusting the gain of the side subband (Es) and middle subband (Em) components of the left and right input channels (XL, XR); - generate a left cross-talk channel (CL) by filtering and delaying the left input channel (XL); - generate a right cross-talk channel (CR) by filtering and time delay of the right input channel (XR); - generate a left output channel (0L) by mixing the left spatially enhanced channel (YL) and the right cross-talk channel (CR); and - generate a right output channel (0R) by mixing the right spatially enhanced channel (YR) and the left cross-talk channel (CL).
[0002]
2. Method, according to claim 1, characterized by the fact that the method still includes generating a left low frequency channel (LFL) and a right low frequency channel (LFR) by: - applying a first bandpass filter (702) to the left input channel (XL) and the right input channel (XR); - applying a second bandpass filter (704) to the outlet of the first bandpass filter (702); and - applying a gain to the output of the second bandpass filter (704); e - generating the left output channel (0L) includes mixing the left spatially enhanced channel (YL), the right cross-talk channel (CR) and the left low-frequency channel (LFL); and - generating the right output channel (OR) includes mixing the spatially enhanced right channel (YR), the left cross-talk channel (CL) and the right low frequency channel (LFR).
[0003]
3. Method, according to claim 2, characterized in that the first and second bandpass filters (702, 704) each have an adjustable center frequency and quality factor (Q).
[0004]
4. Method, according to claim 1, characterized by the fact that the method still includes generating a left high frequency channel (HFL) and a right high frequency channel (HFR) by: - applying a high pass filter (708 ) to the left input channel (XL) and the right input channel (XR); and - applying a gain to the output of the high pass filter (708); e - generating the left output channel (OL) includes mixing the left spatially enhanced channel (YL), the right cross-talk channel (CR) and the left high-frequency channel (HFL); and - generating the right output channel (OR) includes mixing the spatially enhanced right channel (YR), the left cross-talk channel (CL) and the right high frequency channel (HFR).
[0005]
5. Method according to claim 4, characterized in that the high pass filter (708) is a second order Butterworth high pass filter.
[0006]
6. Method, according to claim 1, characterized by the fact that the method still includes generating a left channel of passage (PL) and a right channel of passage (PR) when applying a gain to the left and right channels of entry (XL , XR); - generating the left output channel (OL) includes mixing the left spatially enhanced channel (YL), the right cross-talk channel (CR) and the left passage channel (PL); and - generating the right output channel (OR) includes mixing the right spatially enhanced channel (YR), the left cross-talk channel (CL) and the right channel of passage (PR).
[0007]
7. Method, according to claim 1, characterized by the fact that the method still includes generating a medium channel (M) by: - adding the left input channel (XL) and the right input channel (XR); and - apply a gain to the added left and right input channels (XL, XR); - generating the left output channel (0L) includes mixing the left spatially enhanced channel (YL), the right cross-talk channel (CR) and the middle channel (M); and - generating the right output channel (OR) includes mixing the spatially enhanced right channel (YR), the left cross-talk channel (CL) and the middle channel (M).
[0008]
8. Method, according to claim 1, characterized by the fact that it generates the left spatially enhanced channel (YL) and the right spatially enhanced channel (YR) by gain adjustment of the side subband components (Es) and components of middle subband (Em) of the left and right input channels (XL, XR) include: - separate the left input channel (XL) into the left subband components (EL), each of the subband components left (EL) corresponding to a frequency band from a group of frequency bands; - separating a right input channel (XR) in the right subband components (ER), each of the right subband components (ER) corresponding to a frequency band from the group of frequency bands; - generate the middle sub-band and the side sub-band components (Em, Es) from the left and right sub-band components (EL, ER); - adjust a gain of the side subband components (Es) relative to the middle subband components (Em); and recombine the adjusted gain of the middle subband and side subband components (Em, Es) to generate the left spatially enhanced channel (YL) and the right spatially enhanced channel (YR);
[0009]
9. Method, according to claim 1, characterized by the fact that: - generating the left spatially enhanced channel (YL) and the right spatially enhanced channel (YR) include applying a first gain to the side subband components (Es) and middle subband components (Em) of the left and right input channels (XL, XR); - generating the left cross-talk channel (CL) includes applying a second gain to the filtered left and delayed input channel (XL); - generating the right cross-talk (CR) channel includes applying the second gain to the filtered, delayed time input (XR) right channel; the method also includes: - generating a left low frequency channel (LFL) and a right low frequency channel (LFR) by: - applying a first bandpass filter (702) to the left input channel (XL) and the right input channel (XR); and - applying a second bandpass filter (704) to the outlet of the first bandpass filter (702); and - applying a third gain to the output of the second bandpass filter (704); - generate a left high frequency channel (HFL) and a right high frequency channel (HFR) by: - applying a high pass filter (708) to the left input channel (XL) and the right input channel (XR) ; and - applying a fourth gain to the outlet of the high pass filter (708); - generate a left-hand channel (PL) and a right-hand channel (PR) by applying a fifth gain to the left and right input channels (XL, XR); and - generate a medium channel (M) by: - adding the left input channel (XL) and the right input channel (XR); e - apply a sixth gain to the added left and right input channels (XL, XR); - generating the left output channel (OL) includes mixing the left spatially enhanced channel (YL), the right cross-talk channel (CR), the left low-frequency channel (LFL), the left high-frequency channel (HFL) , the left channel of passage (PL) and the middle channel (M); and - generating the right output channel (0R) includes mixing the spatially enhanced right channel (YR), the left cross-talk channel (CL), the right low frequency channel (LFR), the right high frequency channel (HFR ), the right-of-way channel (PR) and the middle channel (M).
[0010]
10. Method, according to claim 9, characterized by the fact that - the first gain is a gain of -12 to 6 dB; - the second gain is an infinite gain up to 0 dB; - the third gain is a gain of 0 to 20 dB; - the fourth gain is a gain of 0 to 20 dB; - the fifth gain is an infinite gain up to 0 dB; -the sixth gain is an infinite gain up to 0 dB.
[0011]
11. Audio processing system, characterized by the fact that it comprises: - a subband spatial enhancer (210) configured to generate a spatially enhanced left channel (YL) and a spatially enhanced right channel (YR) by adjusting component gain side subband (Es) and middle subband components (Em) of a left input channel (XL) and a right input channel (XR); - a cross-talk simulator (215) configured to: - generate a left cross-talk channel (CL) by filtering and time delay of the left input channel (XL); and - generate a right cross-talk (CR) channel by filtering and time delay of the right input channel (XR); and - a mixer (230) configured to: - generate a left output channel (OL) by mixing the left spatially enhanced channel (YL) and the right cross-talk channel (CR); and - generate a right output channel (0R) by mixing the right spatially enhanced channel (YR) and the left cross-talk channel (CL).
[0012]
12. System according to claim 11, characterized in that the system (200) still includes a frequency booster (225) configured to generate a left low frequency channel (LFL) and a right low frequency channel (LFR ), the frequency booster (225) including: - a first bandpass filter (702) configured to filter the left input channel (XL) and the right input channel (XR); and - a second bandpass filter (704) configured to filter the output of the first bandpass filter (702); and - a low frequency filter gain (706) to apply a gain to the output of the second bandpass filter (704); - the mixer (230) configured to generate the left output channel (0L) includes the mixer (230) being configured to mix the left spatially enhanced channel (YL), the right cross-talk channel (CR) and the low channel left frequency (LFL); and - the mixer (230) configured to generate the right output channel (OR) includes the mixer (230) being configured to mix the right spatially enhanced channel (YR), the left cross-talk channel (CL) and the low frequency right (LFR).
[0013]
13. System according to claim 12, characterized in that the first and second bandpass filters (702, 704) each have an adjustable center frequency and quality factor (Q).
[0014]
14. System according to claim 11, characterized in that the system (200) also includes a frequency reinforcer (225) configured to generate a left high frequency channel (HFL) and a right high frequency channel (HFR ), the frequency booster (225) including: - a high pass filter (708) configured to filter the left input channel (XL) and the right input channel (XR); and - a high frequency filter gain (710) to apply a gain to the output of the high pass filter (708); - the mixer (230) configured to generate the left output channel (OL) includes the mixer (230) being configured to mix the left spatially enhanced channel (YL), the right cross-talk channel (CR) and the left channel of high frequency (HFL); and - the mixer (230) configured to generate the right output channel (OR) includes the mixer (230) being configured to mix the spatially enhanced right channel (YR), the left cross-talk channel (CL) and the right channel high frequency (HFR).
[0015]
15. System according to claim 14, characterized in that the high pass filter (708) is a second order Butterworth high pass filter.
[0016]
16. System according to claim 11, characterized in that the system (200) still includes a passage (220) configured to generate a left channel of passage (PL) and a right channel of passage (PR), the passage (220) including a pass gain (604) configured to apply a gain to the left and right input channels (XL, XR); - the mixer (230) configured to generate the left output channel (OL) includes the mixer (230) being configured to mix the left spatially enhanced channel (YL), the right cross-talk channel (CR) and the left channel of passage (PL); and - the mixer (230) configured to generate the right output channel (OR) includes the mixer (230) being configured to mix the spatially enhanced right channel (YR), the left cross-talk channel (CL) and the right channel of passage (PR).
[0017]
17. System according to claim 11, characterized in that the system (200) still includes a passage (220) configured to generate a medium channel (M), the passage (220) including: - a combiner (602) configured to add the left input channel (XL) and the right input channel (XR); and - an average gain configured to apply a gain to the added left and right input channels (XL, XR); - the mixer (230) configured to generate the left output channel (0L) includes the mixer (230) being configured to mix the left spatially enhanced channel (YL), the right cross-talk channel (CR) and the left middle channel (ML); and - the mixer (230) configured to generate the right output channel (OR) includes the mixer (230) being configured to mix the spatially enhanced right channel (YR), the left cross-talk channel (CL) and the middle channel right (MR).
[0018]
18. System, according to claim 11, characterized by the fact that the subband spatial enhancer (210) configured to generate the left spatially enhanced channel (YL) and the right spatially enhanced channel (YR) by adjusting the gain of the side subband components (Es) and middle subband components (Em) of the left input channel (XL) and the right input channel (XR) include the subband spatial enhancer (210) being configured to : - separate the left input channel (XL) into the left subband components (EL), each of the left subband components (EL) corresponding to a frequency band from a group of frequency bands; - separating a right input channel (XR) in the right subband components (ER), each of the right subband components (ER) corresponding to a frequency band from the group of frequency bands; - generate the middle sub-band and the side sub-band components (Em, Es) from the left and right sub-band components (EL, ER); - adjust a gain of the side subband components (Es) relative to the middle subband components (Em); and - recombine the adjusted gain of the middle subband and side subband components (Em, Es) to generate the left spatially enhanced channel (YL) and the right spatially enhanced channel (YR).
[0019]
19. System according to claim 11, characterized by the fact that the subband spatial enhancer (210) configured to generate the left spatially enhanced channel (YL) and the right spatially enhanced channel (YR) include the spatial enhancer of subband (210) being configured to apply a first gain to the side subband components (Es) and middle subband components (Em) of the left and right input channels (XL, XR); - the cross-talk simulator (215) configured to generate the left cross-talk channel (CL) includes the cross-talk simulator (215) being configured to apply a second gain to the left and delayed filtered input channel (XL) ; - the cross-talk simulator (215) configured to generate the right cross-talk channel (CR) includes the cross-talk simulator (215) being configured to apply the second gain to the filtered and delayed time input (XR) channel ; the system (200) also includes: - a frequency booster (225) configured to generate a left low frequency channel (LFL), a right low frequency channel (LFR), a left high frequency channel (HFL) and a high frequency right channel (HFR), the frequency booster (225) including: - a first bandpass filter (702) configured to filter the left input channel (XL) and the right input channel (XR); and - a second bandpass filter (704) configured to filter the output of the first bandpass filter (702); - a low frequency filter gain (705) configured to apply a third gain to the output of the second bandpass filter (704) to generate the left low frequency channel (LFL) and right low frequency channel (LFR); - a high pass filter (708) configured to filter the left input channel (XL) and the right input channel (XR); and - a high frequency filter gain (710) configured to apply a fourth gain to the output of the high pass filter (708) to generate the left high frequency channel (HFL) and the right high frequency channel (HFR); - a passage (220) configured to generate a left passage channel (PL), a right passage channel (PR) and a middle channel (M), the passage (220) including: - a passage gain (604) configured to apply a fifth gain to the left and right input signals (XL, XR) to generate the left channel of passage (PL) and the right channel of passage (PR); - a combiner (602) configured to add the left input channel (XL) and the right input channel (XR); and - an average gain configured to apply a sixth gain to the added left and right input channels (XL, XR) to generate the left middle channel (ML) and the right middle channel (MR); - the mixer (230) configured to generate the left output channel (OL) includes the mixer (230) being configured to mix the left spatially enhanced channel (YL), the right cross-talk channel (CR), the low channel left frequency (LFL), the left high frequency channel (HFL), the left pass channel (PL) and the middle channel (M); and - the mixer (230) configured to generate the right output channel (OR) includes the mixer (230) being configured to mix the right spatially enhanced channel (YR), the left cross-talk channel (CL), the right low frequency (LFR), the right high frequency channel (HFR), the right channel of passage (PR) and the middle channel (M).
[0020]
20. Non-transient computer readable media configured to store the method, characterized by the fact that it performs the steps of the method on a processor, causing the processor to: - receive an input audio signal (X) comprising a left input channel (XL) and a right input channel (XR); - manages a spatially enhanced left channel (YL) and a spatially enhanced right channel (YR) by adjusting the gain of the side subband components (Es) and middle subband components (Em) of the left and right input channels (XL, XR); - manages a left cross-talk channel (CL) by filtering and delaying the left input channel (XL); - manages a right cross-talk channel (CR) by filtering and time delay of the right input channel (XR); - generate a left output channel (OL) by mixing the left spatially enhanced channel (YL) and the right cross-talk channel (CR); and generate a right output channel (OR) by mixing the right spatially enhanced channel (YR) and the left cross-talk channel (CL).

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法律状态:
2020-04-14| B06A| Notification to applicant to reply to the report for non-patentability or inadequacy of the application [chapter 6.1 patent gazette]|

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2020-09-08| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2020-11-24| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 12/01/2017, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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US201662280121P| true| 2016-01-19|2016-01-19|

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US62/280,121|2016-01-19|

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US201662388367P| true| 2016-01-29|2016-01-29|

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US62/388,367|2016-01-29|

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PCT/US2017/013249|WO2017127286A1|2016-01-19|2017-01-12|Audio enhancement for head-mounted speakers|

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