US 6,606,388 B1Granted

Method and system for enhancing audio signals

AssigneeArboretum Systems, Inc.

InventorsChris Townsend, Aram Lindahl

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Abstract

A technique for enhancing audio signals generated from compressed digital audio files is described. The technique uses a Bass Maximizer module, a Harmonic Exciter module and a Quasi Stereo module. The Bass Exciter module enhances the intensity, depth and punch of the bass audio content by creating harmonic sequences from low frequency components contained in the original input signal. The Harmonic Exciter module adds to the treble audio content of the original input signal by generating harmonic series from the high frequency components contained in the input signal. The Quasi Stereo Module creates a stereo image of the enhanced input signal by adding and subtracting delayed and filtered versions of the enhanced input signal with itself to create left and right channeled stereo-like outputs. The technique provides a useful tool to regenerate from an audio signal more pleasant and joyful sounds.

Claims26

Dependent claims

A method for enhancing the quality of an audio signal, the method comprising:

separating said audio signal into a first signal having low frequency components of said audio signal and a second signal having high frequency components of said audio signal;
processing said first signal, while delaying said second signal by a first amount of time taken for said processing of said first signal to finish, to enhance first characteristics of said first signal such that said first signal after processing can still be aligned temporally with the said second signal;
and processing delayed said second signal while delaying processed said first signal by a second amount of time taken for said processing of delayed said second signal to finish, to enhance second characteristics of delayed said second signal such that delayed said second signal after processing can be aligned temporally with processed said first signal;
or
processing said delayed second signal, while delaying said first signal by a second amount of time taken for said processing of said second signal to finish, to enhance second characteristics of said second signal such that said second signal after processing can still be aligned temporally with the said first signal;
and processing delayed said first signal while delaying processed said second signal by a first amount of time taken for said processing of delayed said first signal to finish, to enhance first characteristics of delayed said first signal such that delayed said first signal after processing can be aligned temporally with processed said second signal;
combining processed and delayed said delayed first signal and processed and delayed said second signal to form a processed audio signal;
and
generating a left-channel audio signal and a right-channel audio signal from said processed audio signal, wherein said left-channel audio signal is generated by adding a delayed and filtered version of said processed audio signal to said processed audio signal, said right-channel audio signal is generated by subtracting a delayed and filtered version of said processed audio signal from said processed audio signal.

6 more elements

An apparatus for enhancing the quality of an audio signal, said apparatus comprising:

a storage for said audio signal;
a bass maximizer, receiving said audio signal from said storage, enhancing low frequency components of said audio signal while delaying high frequency components of said audio signal by a first amount of time to ensure that said low and high frequency components are temporally aligned;
a harmonic exciter, coupled to said bass maximizer, enhancing said high frequency components of said audio signal while delaying said enhanced low frequency components by a second amount of time to ensure that said low and high frequency components are temporally aligned, wherein said harmonic exciter produces a processed audio signal;
and
a quasi stereo module having first and second sound channels, said quasi stereo module coupled to said harmonic exciter and adding a delayed and filtered version of said processed audio signal to said processed audio signal for said first sound channel and subtracting a delayed and filtered version of said processed audio signal from said processed audio signal for said second sound channel.

2 more elements

A computer readable medium containing program code for enhancing the quality of an audio signal, said computer readable medium comprising:

program code for separating said audio signal into a first signal having low frequency components of said audio signal and a second signal having high frequency components of said audio signal;
program code for processing said first signal, while delaying said second signal by a first amount of time taken for said program code for processing said first signal to finish, to enhance first characteristics of said first signal such that said first signal after processing can still be aligned temporally with the said delayed second signal;
and processing delayed said second signal while delaying processed said first signal by a second amount of time taken for said processing of delayed said second signal to finish, to enhance second characteristics of delayed said second signal such that delayed said second signal after processing can be aligned temporally with processed said first signal;
or
program code for processing said second signal, while delaying said first signal by a second amount of time taken for said program code for processing said second signal to finish, to enhance second characteristics of said second signal such that said second signal after processing can still be aligned temporally with the said delayed first signal;
and processing delayed said first signal while delaying processed said second signal by a first amount of time taken for said processing of delayed said first signal to finish, to enhance first characteristics of delayed said first signal such that delayed said first signal after processing can be aligned temporally with processed said second signal;
program code for combining processed and delayed said first signal and processed and delayed said second signal to form a processed audio signal;
and
program code for generating a left-channel audio signal and a right-channel audio signal from said processed audio signal, wherein said left-channel audio signal is generated by adding a delayed and filtered version of said processed audio signal to said processed audio signal, said right-channel audio signal is generated by subtracting a delayed and filtered version of said processed audio signal from said processed audio signal.

6 more elements

Dependencies are inferred from the claim text.