Systems and methods for audio processing
First Claim
1. A method of processing audio based on spatial position information, the method comprising:
- receiving one or more digital signals, each of said one or more digital signals having information about a spatial position of a sound source relative to a listener;
selecting a digital filter based on the spatial position information, the digital filter configured to approximate a head-related transfer function (HRTF), wherein the digital filter is selected from the following;
a first digital filter having a first frequency response comprising a first peak at a first frequency, a second peak at a second frequency higher than the first frequency, a single trough between the first peak and the second peak, a substantially flat response in a first frequency range from 30 Hz to 200 Hz, below a frequency of the first peak, an increasing response from 200 Hz until the first peak, and an attenuating response that attenuates a second frequency range from the second peak until a highest frequency of the first frequency response, anda second digital filter having a second frequency response comprising a first trough at a third frequency, a second trough at a fourth frequency higher than the third frequency, a substantially flat response in a third frequency range from 30 Hz until 1100 Hz, below a frequency of the first trough, and an emphasizing response that emphasizes a fourth frequency range higher in frequency than the fourth frequency of the second trough; and
applying the selected digital filter to the one or more digital signals so as to produce a left filtered signal and a right filtered signal, each of the left and right filtered signals configured to have a simulated effect of the HRTF applied to the sound source.
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Abstract
Systems and methods for audio signal processing are disclosed, where a discrete number of simple digital filters are generated for particular portions of an audio frequency range. Studies have shown that certain frequency ranges are particularly important for human ears'"'"' location-discriminating capability, while other ranges are generally ignored. Head-Related Transfer Functions (HRTFs) are examples response functions that characterize how ears perceive sound positioned at different locations. By selecting one or more “location-critical” portions of such response functions, one can construct simple filters that can be used to simulate hearing where location-discriminating capability is substantially maintained. Because the filters can be simple, they can be implemented in devices having limited computing power and resources to provide location-discrimination responses that form the basis for many desirable audio effects.
76 Citations
25 Claims
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1. A method of processing audio based on spatial position information, the method comprising:
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receiving one or more digital signals, each of said one or more digital signals having information about a spatial position of a sound source relative to a listener; selecting a digital filter based on the spatial position information, the digital filter configured to approximate a head-related transfer function (HRTF), wherein the digital filter is selected from the following; a first digital filter having a first frequency response comprising a first peak at a first frequency, a second peak at a second frequency higher than the first frequency, a single trough between the first peak and the second peak, a substantially flat response in a first frequency range from 30 Hz to 200 Hz, below a frequency of the first peak, an increasing response from 200 Hz until the first peak, and an attenuating response that attenuates a second frequency range from the second peak until a highest frequency of the first frequency response, and a second digital filter having a second frequency response comprising a first trough at a third frequency, a second trough at a fourth frequency higher than the third frequency, a substantially flat response in a third frequency range from 30 Hz until 1100 Hz, below a frequency of the first trough, and an emphasizing response that emphasizes a fourth frequency range higher in frequency than the fourth frequency of the second trough; and applying the selected digital filter to the one or more digital signals so as to produce a left filtered signal and a right filtered signal, each of the left and right filtered signals configured to have a simulated effect of the HRTF applied to the sound source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for processing audio based on spatial position information, the system comprising:
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a filter selection component configured to select a digital filter based on spatial position information of a sound source relative to a listener, the spatial position information being encoded in input audio, the selected digital filter configured to approximate a head-related transfer function (HRTF), wherein the selected digital filter is selected from the following; a first digital filter having a first frequency response comprising a first peak at a first frequency, a second peak at a second frequency higher than the first frequency, a single trough between the first peak and the second peak, a substantially flat response from 30 Hz to 200 Hz, in a first frequency range below a frequency of the first peak, and an attenuating response that attenuates a second frequency range higher in frequency than the second frequency of the second peak, and a second digital filter having a second frequency response comprising a first trough at a third frequency, a second trough at a fourth frequency higher than the third frequency, a single peak between the first trough and the second trough, a substantially flat response in a third frequency range from 30 Hz until 1100 Hz, below a frequency of the first trough, and an emphasizing response that emphasizes a fourth frequency range higher in frequency than the fourth frequency of the second trough; and a filter application component configured to apply the selected digital filter to the input audio so as to produce a left filtered signal and a right filtered signal, each of the left and right filtered signals configured to have a simulated effect of the HRTF applied to the sound source. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. Non-transitory physical computer storage comprising instructions stored thereon for executing, in one or more processors, components for processing audio based on spatial position information, the components comprising:
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a filter selection component configured to select a digital filter based on spatial position information of a sound source relative to a listener, the spatial position information being encoded in input audio, the selected digital filter configured to approximate a head-related transfer function (HRTF), wherein the selected digital filter is selected from the following; a first digital filter having a first frequency response comprising a first peak at a first frequency, a second peak at a second frequency higher than the first frequency, a single trough between the first peak and the second peak, a substantially flat response in a first frequency range from 30 Hz to 200 Hz, below a frequency of the first peak, and an attenuating response that attenuates a second frequency range higher in frequency than the second frequency of the second peak, and a second digital filter having a second frequency response comprising a first trough at a third frequency, a second trough at a fourth frequency higher than the third frequency, a single peak between the first trough and the second trough, a substantially flat response in a third frequency range from 30 Hz until 1100 Hz, below a frequency of the first trough, and an emphasizing response that emphasizes a fourth frequency range higher in frequency than the fourth frequency of the second trough; and a filter application component configured to apply the selected digital filter to the input audio so as to produce a left filtered signal and a right filtered signal, each of the left and right filtered signals configured to have a simulated effect of the HRTF applied to the sound source. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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Specification