Digital self-adapting graphic equalizer and method

A digital self-adaptive graphic equalization method to equalize the affects of an audio system on an audio signal, comprising:

• receiving an output signal from the audio system, the output signal being generated by the audio system in response to the audio signal;
• dividing the output signal into programmed N sub-bands and filtering a programmed ith sub-band of the output signal, where i=1−N;
• dividing the audio signal into the same programmed N sub-bands and filtering a programmed ith sub-band of the audio signal, where i=1−N;
• determining a difference between the ith filtered sub-band of the audio signal and the ith filtered sub-band of the output signal;
• adjusting the gain of an ith equalizing filter of an adaptive graphic equalizer in response the difference between the ith filtered sub-band of the audio and output signals, the equalizing filters having different center frequencies and spanning a predetermined audio bandwidth;
• and
• generating an equalized audio signal and providing the equalized audio signal to the audio system.

A digital self-adaptive graphic equalization method to equalize the affects of a speaker-microphone system and the environment on an audio signal, comprising:

• receiving an output signal from the audio system, the output signal being generated by the audio system in response to the audio signal;
• dividing the output signal into N programmed sub-bands and filtering a programmed ith sub-band of the output signal, where i=1−N;
• dividing the audio signal into the same N sub-bands and filtering an ith sub-band of the audio signal, where i=1−N;
• time averaging the N sub-bands of the filtered output signal;
• time averaging the N sub-bands of the filtered audio signal;
• normalizing the time averaged N sub-bands of the filtered output signal and the time averaged N sub-bands of the filtered audio signal;
• determining a difference between the ith filtered sub-band of the audio signal and the ith filtered sub-band of the output signal;
• adjusting the gain of an ith equalizing filter of an adaptive graphic equalizer in response the difference between the ith filtered sub-band of the audio and output signals, the equalizing filters having different center frequencies and spanning a predetermined audio bandwidth;
• and
• generating an equalized audio signal and providing the equalized audio signal to the audio system.

A self-adaptive graphic equalizer operable to equalize the affects of an audio system on an audio signal, comprising:

• an adaptive graphic equalizer having a plurality of equalizing filters, the plurality of equalizing filters having different center frequencies and spanning a predetermined audio bandwidth, each equalizing filter being operable to filter an ith sub-band of the audio signal;
• a plurality of first filters coupled to the audio system, each first filter being operable to filter an ith sub-band of an output signal of the audio system;
• a plurality of second filters receiving the audio signal, each second filter being operable to filter an ith sub-band of the audio signal;
• a gain adjuster operable to adjust the ith sub-band of the adaptive graphic equalizer in response to a difference in the ith sub-band of the filtered output signal from the plurality of first filters and the ith sub-band of the filtered audio signal from the plurality of second filters;
• a time averaging circuit coupled to the plurality of first filters and the plurality of second filters and operable to compute time averages of the plurality of filtered output signals and the plurality of filtered audio signals;
• a dB converter coupled to the time averaging circuit operable to convert the time averaged plurality of filtered output signals and the time averaged plurality of filtered audio signals to dB space;
• and
• a normalization circuit receiving the time averaged plurality of filtered output signals and the time averaged plurality of filtered audio signals in dB space, and adjusting the signals so that:
• ΣirLi=ΣioLi
• where rLi is the time averaged ith filtered output signal in dB space, and oLi is the time averaged ith filtered audio signal in dB space.

A digital self-adaptive graphic equalization method to equalize the affects of an audio system on an audio signal, comprising:

• receiving an output signal from the audio system, the output signal being generated by the audio system in response to the audio signal;
• dividing the output signal into N sub-bands and filtering an ith sub-band of the output signal, where i=1−N;
• dividing the audio signal into the same N sub-bands and filtering an ith sub-band of the audio signal, where i=1−N;
• determining a difference between the ith filtered sub-band of the audio signal and the ith filtered sub-band of the output signal;
• adjusting the gain of an ith equalizing filter of an adaptive graphic equalizer in response the difference between the ith filtered sub-band of the audio and output signals, the equalizing filters having different center frequencies and spanning a predetermined audio bandwidth;
• generating an equalized audio signal and providing the equalized audio signal to the audio system;
• computing a time averages of the plurality of filtered output signals and the plurality of filtered audio signals;
• converting the time averaged plurality of filtered output signals and the time averaged plurality of filtered audio signals to dB space;
• and
• adjusting the time averaged plurality of filtered output signals and the time averaged plurality of filtered audio signals in dB space so that:
• ΣirLi=ΣioLi
• where rLi is the time averaged ith filtered output signal in dB space, and oLi is the time averaged ith filtered audio signal in dB space.