Method and apparatus for two channels of sound having directional cues
First Claim
1. A method for generating two channels of sound signals from a multiplicity of sound signals, said multiplicity of sound signals comprising a first plurality of front signals and second plurality of rear signals, said method comprising the steps of:
- applying a 90°
phase shift to the second plurality of rear sound signals;
applying head related transfer functions to the phase shifted second plurality of rear sound signals to generate modified rear sound signals, said modified rear signals comprising signals identified as corresponding to the first channel and signals corresponding to the second channel;
said front signals comprising signals identified as corresponding to the first channel and signals corresponding to the second channel;
combining the signals corresponding to the first channel to generate a first combined signal, the modified rear signals corresponding to the first channel being subtracted from the remaining signals corresponding to the first channel;
combining the signals corresponding to the second channel to generate a second combined signal; and
recording the first combined signal and second combined signal on a first audio track and second audio track of a film respectively.
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Abstract
The system and method of the present invention provides enhanced surround sound effects. In one embodiment, 90° phase shift and copy of the modified head related transfer functions (HRTF) are applied to each rear sound signal. The modified HRTF for each rear signal is generated by removing the head related transfer function corresponding to the front center signal from the HRTF corresponding to the rear sound signal. This provides the audible effect of distinguishing more clearly sounds originating in front of the listener or to the rear of the listener while not limiting the perceived bandwidth of the signal. The rear signals corresponding to the first channel are inverted. The front and rear signals for each corresponding channel are then combined. The two channels, generated can be stored on media, such as film, and subsequently read and input to a surround sound decoder to generate enhanced surround sound output.
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Citations
10 Claims
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1. A method for generating two channels of sound signals from a multiplicity of sound signals, said multiplicity of sound signals comprising a first plurality of front signals and second plurality of rear signals, said method comprising the steps of:
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applying a 90°
phase shift to the second plurality of rear sound signals;applying head related transfer functions to the phase shifted second plurality of rear sound signals to generate modified rear sound signals, said modified rear signals comprising signals identified as corresponding to the first channel and signals corresponding to the second channel; said front signals comprising signals identified as corresponding to the first channel and signals corresponding to the second channel; combining the signals corresponding to the first channel to generate a first combined signal, the modified rear signals corresponding to the first channel being subtracted from the remaining signals corresponding to the first channel; combining the signals corresponding to the second channel to generate a second combined signal; and
recording the first combined signal and second combined signal on a first audio track and second audio track of a film respectively.
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2. A method for generating two channels of sound signals from a multiplicity of sound signals, said multiplicity of sound signals comprising a first plurality of front signals and second plurality of rear signals, said method comprising the steps of:
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applying a 90°
phase shift to the second plurality of rear sound signals;applying head related transfer functions to the phase shifted second plurality of rear sound signals to generate modified rear sound signals, said modified rear signals comprising signals identified as corresponding to the first channel and signals corresponding to the second channel; said front signals comprising signals identified as corresponding to the first channel and signals corresponding to the second channel; combining the signals corresponding to the first channel to generate a first combined signal, the modified rear signals corresponding to the first channel being subtracted from the remaining signals corresponding to the first channel; combining the signals corresponding to the second channel to generate a second combined signal; and
recording the first combined signal and second combined signal.
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3. A method for generating two channels of sound signals from a multiplicity of sound signals, said multiplicity of sound signals comprising a first plurality of front signals and second plurality of rear signal, said method comprising the steps of:
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applying a 90 degree phase shift to the second plurality of rear sound signals to generate phase shifted rear sound signals; applying head related transfer functions to the phase shifted rear sound signals to generate modified rear sound signals, said modified rear signals comprising signals identified as corresponding to the first channel and signals corresponding to the second channel; selectively inverting modified rear signals such the modified rear signals corresponding to the first channel are inverted; said front signals comprising signals identified as corresponding to the first channel and signals corresponding to the second channel; combining the signals corresponding to the first channel to generate a first combined signal; combining the signals corresponding to the second channel to generate a second combined signal; and
further comprising the step of applying additional spatial cues to the selected ones of the first plurality of front sound signals to generate spatial cued selected front signals, said spatial cued selected front signals comprising signals identified as corresponding to a first channel and signals corresponding to a second channel and respectively recording the first combined signal and second combined signal on a first audio track and second audio track of a film media.
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4. An apparatus for generating two channels of sound signals from a multiplicity of sound signals, said multiplicity of sound signals comprising a first plurality of front signals and second plurality of rear signals, said apparatus comprising of:
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a plurality of inputs for receiving a plurality of sound signals; a processing device for receiving a plurality of sound signals, said processing device, applying a 90°
phase shift to the second plurality of rear sound signals, applying head related transfer functions to the second phase shifted plurality of rear sound signals to generate modified rear sound signals, said front signals comprising signals identified as corresponding to a first channel and signals corresponding to the second channel, said modified rear sound signals comprising signals identified as corresponding to a first channel and signals corresponding to a second channel, combining the signals corresponding to the first channel to generate a first combined signal, the modified rear signals being subtracted form the remaining signals corresponding to the first channel, combining the signals corresponding to the second channel to generate a second combined signal, and recording the first combined signal and second combined signal on a first audio track and second audio track of a film media.
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5. An apparatus for generating two channels of sound signals from a multiplicity of sound signals, said multiplicity of sound signals comprising a first plurality of front signals and second plurality of rear signals, said apparatus comprising of:
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a plurality of inputs for receiving a plurality of sound signals; a processing device for receiving a plurality of sound signals, said processing device, applying a 90°
phase shift to the second plurality of rear sound signals, applying head related transfer functions to the second phase shifted plurality of rear sound signals to generate modified rear sound signals, said front signals comprising signals identified as corresponding to a first channel and signals corresponding to the second channel, said modified rear sound signals comprising signals identified as corresponding to a first channel and signals corresponding to a second channel, combining the signals corresponding to the first channel to generate a first combined signal, the modified rear signals being subtracted form the remaining signals corresponding to the first channel, combining the signals corresponding to the second channel to generate a second combined signal, and causing recording the first combined signal and second combined signal.
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6. A method for generating surround sound signals comprising the steps of:
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accessing a first channel and second channel of encoded sound signals stored on media, said sound signals encoded by processing a first plurality of front signals and second plurality or rear signals by applying a 90 degree phase shift to the second plurality of rear sound signals, applying head related transfer functions to the phase shifted second plurality of rear sound signals to generate modified rear sound signals, said modified rear signals comprising signals identified as corresponding to the first channel and signals corresponding to the second channel, said front signals comprising signals corresponding to the first channel and signals corresponding to the second channel, combining the signals corresponding to the first channel to generate a first combined signal that is stored as the first channel on the media, wherein the modified rear signals are subtracted from the remaining signals corresponding to the first channel, and combining the signals corresponding to the second channel to generate a second combined signal that is stored as the second channel on the media; inputting the first channel of encoded sound signals retrieved to a first channel input to a surround sound decoder; inputting the second channel of encoded sound signals retrieved to a second channel input to the surround sound decoder; said surround sound decoder decoding the encoded sound signals input and generating a multiplicity of surround sound signals. - View Dependent Claims (7, 8, 9)
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10. A machine readable medium containing two channels of signals which, when executed by a surround sound system, causes the system to generate enhanced surround sound, said signals generated by processing a first plurality of front signals and second plurality of rear signals by applying a 90 degree phase shift to the second plurality of rear sound signals, applying head related transfer functions to the phase shifted second plurality of rear sound signals to generate modified rear sound signals, said modified rear signals comprising signals identified as corresponding to the first channel and signals corresponding to the second channel, said front signals comprising signals corresponding to the first channel and signals corresponding to the second channel, combining the signals corresponding to the first channel to generate a first combined signal that is stored as the first channel on the media, wherein the modified rear signals corresponding to the first channel are subtracted from the remaining signals corresponding to the first channel, and combining the signals corresponding to the second channel to generate a second combined signal that is stored as the second channel on the media.
Specification