KR20070050930A - System for and method of audio signal processing for presentation in a high-noise environment - Google Patents

Abstract

The present invention relates to novel systems, methods and circuits useful for obtaining quality sound representations in high-noise environments. Specifically, the present invention provides an audio signal processing system, method and circuit. Furthermore, the present invention provides a method of hard programming an adjustment operation to a multi-band equalizer that compensates for anomalies associated with an expected listening environment.

Description

SYSTEM AND METHOD FOR PROCESSING SOUND IN HIGH NOISE ENVIRONMENTS {SYSTEM FOR AND METHOD OF AUDIO SIGNAL PROCESSING FOR PRESENTATION IN A HIGH-NOISE ENVIRONMENT}

The present invention relates to novel systems, methods and circuits useful for obtaining quality sound representations in high-noise environments. In particular, the present invention provides a system, method and circuit for processing an audio signal. The present invention further provides a hard-programming adjustment method with a multi-band equalizer that compensates for the exception associated with expected listening.

In high-noise environments such as moving vehicles, getting a good sound representation remains a challenge. For example, in this environment the bass response of the system is generally inadequate. While the bass response is boosted by the equalizer to compensate for inadequacy, this approach can lead to inaccurate treble response, thus degrading the quality of the sound. In addition to inaccurate treble response, bass boost can undesirably increase the dynamic range of the acoustic representation. In a noisy environment, there is a very small audio range between the volume floor set by the noise (typically around 80 dB in moving vehicles) and the volume ceiling set by the physiological characteristics of human hearing. Increasing the dynamic range of sound represented in a noisy environment is aesthetically undesirable. Because the acoustic level approaches the physiological volume ceiling of the auditory, it results in an unpleasant, annoying or even painful response. Thus, there is a need for a new approach for quality sound representation in high-noise environments.

Typical consumer acoustic transducers, such as commercial speakers, are acoustically effective if operated between about 600 and 1000 cycles. To compensate for the invalid operation of acoustic transducers outside this range, systems often use various characteristic speakers or amplifiers. These speakers and amplifiers are very expensive. A system that compensates for these invalid behaviors without using extra hardware or expensive hardware would be very useful.

Today, the dynamic range of sound in a movie is created and mixed in an environment such as the size of a movie theater. It's hard to get good quality movie sound in a small-sized environment such as in the home entertainment area or in cars. In small environments, audio standing waves often produce disturbing acoustic signals at standing wave frequencies. In a given small size environment, this particular standing wave can be compensated for to produce a high-quality sound representation.

Finally, in contrast to paying close attention to movie sound and music, the audio used in electronic video games is often mixed randomly. This randomly mixed audio does not give the listener complete, balanced audio. The audio frequency width over the entire dynamic range can be enhanced to provide high quality audio.

The present invention relates to novel systems, methods and circuits useful for obtaining quality sound representations in high-noise environments. In one aspect, the present invention provides an audio signal processing system. In one embodiment, the system adjusts the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and adjusts the amplitude of the high frequency portion of the audio signal corresponding to the audible treble sound in the opposite direction to equalize the audio signal. A primary equalizer for generating a first equalizer, the primary equalizer crossing each other between the adjusting range and the crossing range of frequencies where the adjusting operation in the opposite direction produces a negligible gain in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; And a mirror equalizer that produces an effect opposite to the primary equalizer.

In another embodiment, the system reduces the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and increases the amplitude of the high frequency portion of the audio signal corresponding to the audible high pitch sound to produce an equalized audio signal. A primary equalizer, said primary equalizer crossing each other between said reduction and said increase producing said negligible gain in an intersection range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; And

And a mirror equalizer that produces an effect opposite to the primary equalizer.

In an alternative embodiment, the system equalizes the audio by adjusting the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and the amplitude of the high frequency portion of the audio signal corresponding to the audible high pitch sound in the opposite direction. A primary equalizer for generating a signal, said primary equalizer intersecting each other between said crossing range of frequencies at which said adjustment operation and said adjustment operation in opposite directions produce negligible gains in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; A mirror equalizer which produces an effect opposite to the primary equalizer; And a final equalizer that adjusts the amplitude of the signal at a preset frequency to relate to acoustic representation anomalies associated with an expected listening environment.

In yet another embodiment, the system generates an equalized audio signal by reducing the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and increasing the amplitude of the high frequency portion of the audio signal corresponding to the audible high pitched sound. A primary equalizer comprising: the primary equalizer crossing each other between the reduction and the increase in the crossing range where the increase produces negligible gain in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; A mirror equalizer which produces an effect opposite to the primary equalizer; And a final equalizer that adjusts the amplitude of the signal at a preset frequency to relate to acoustic representation anomalies associated with an expected listening environment.

The system of the present invention may further comprise a speaker system responsive to the output signal of the mirror equalizer.

In one embodiment, the crossing range is between 600 Hz and 1,000 Hz. In another embodiment, the primary equalizer and the mirror equalizer may adjust the amplitude according to a linear frequency function.

In one embodiment, the compressor may compress the audio signal by attenuating the high amplitude portion of the audio signal. Optionally, the compressor may compress the audio signal by amplifying the low amplitude portion of the audio signal. In certain embodiments, the compressor may compress the dynamic range of the audio signal to about 10 dB or less.

In another embodiment, the primary equalizer uses one or more filters to adjust the amplitude of the high frequency portion of the audio signal, and the mirror equalizer uses one or more filters to apply the 1 to the high frequency portion of the audio signal. The opposite effect is applied to the differential equalizer, the filter being equal and opposite to the audio signal.

Optionally, the primary equalizer uses one or more filters to adjust the amplitude of the low frequency portion of the audio signal, and the mirror equalizer uses one or more filters to match the primary equalizer to the low frequency portion of the audio signal. The opposite action may be applied, but the filters may apply the same and opposite action to the audio signal.

In one embodiment, the primary equalizer may reduce the amplitude of the low frequency portion of the signal by about 10 dB at 100 Hz. In another embodiment, the primary equalizer may increase the amplitude of the high frequency portion of the signal by about 8 dB at 8 kHz.

The mirror equalizer may increase the amplitude of the low frequency portion of the signal by 10 dB at 100 Hz. Optionally, the mirror equalizer can reduce the amplitude of the high frequency portion of the signal by 8 dB at 8 kHz.

In another embodiment, the mirror equalizer may increase the amplitude of the low frequency portion of the signal by 10 dB at 100 Hz. In a further embodiment, the mirror equalizer may reduce the amplitude of the high frequency portion of the signal by 8 dB at 8 kHz.

In a further embodiment, the mirror equalizer may reduce the amplitude of the low frequency portion of the signal by 10 dB at 100 Hz. In a further embodiment, the mirror equalizer may increase the amplitude of the high frequency portion of the signal by 8 dB at 8 kHz.

In another aspect, the present invention provides an audio signal processing method. In one embodiment, the method adjusts the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and adjusts the amplitude of the high frequency portion of the audio signal corresponding to the audible treble sound in the opposite direction to adjust the audio signal. First equalizing, said first equalizing step intersecting each other between said adjustment range and said crossing range of frequencies at which the adjustment operation in the opposite direction produces negligible gain in the intersection range; Compressing a dynamic range of the audio signal; And mirror equalizing the audio signal in a manner opposite to the first equalization.

In another embodiment, the method adjusts the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and adjusts the amplitude of the high frequency portion of the audio signal corresponding to the audible high pitch sound in the opposite direction to adjust the audio signal. First equalizing, said first equalizing step intersecting each other between said adjustment range and said crossing range of frequencies at which the adjustment operation in the opposite direction produces negligible gain in the intersection range; Compressing a dynamic range of the audio signal; Mirror equalizing the audio signal in a manner opposite to the first equalization step; And adjusting the amplitude of the signal at a preset frequency so as to relate to an acoustic representation anomaly associated with an expected listening environment.

In another aspect, the present invention provides an audio signal processing circuit. In one embodiment, adjusting the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and the amplitude of the high frequency portion of the audio signal corresponding to the audible high pitch sound in the opposite direction to generate an equalized audio signal. A primary equalizer, comprising: the primary equalizer crossing each other between the crossing range of frequencies where the adjusting operation and the adjusting operation in the opposite direction produce negligible gains in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; And a mirror equalizer that produces an opposite effect to the first equalizer.

In an alternative embodiment, the circuit adjusts the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and adjusts the amplitude of the high frequency portion of the audio signal corresponding to the audible treble sound in the opposite direction to equalize the audio. A primary equalizer for generating a signal, said primary equalizer intersecting each other between said crossing range of frequencies at which said adjustment operation and said adjustment operation in opposite directions produce negligible gains in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; A mirror equalizer which produces an effect opposite to the primary equalizer; And a final equalizer that adjusts the amplitude of the signal at a preset frequency so as to relate to acoustic representation anomalies associated with an expected listening environment.

In another aspect, the present invention provides a method of hard-programming adjustment operations to one or more multi-band equalizers that compensate for anomalies associated with an expected listening environment. The hard program method comprises: representing a test audio signal with the expected listening environment; Detecting an audio representation anomaly associated with the expected listening environment from a response resulting from the test audio signal; Determining a frequency associated with the anomaly of the audio signal; In the multiband equalizer, adjusting an amplitude at the frequency to compensate for the anomaly; And hard programming the adjustment operation at the frequency with one or more multi-band equalizers.

In an alternative embodiment, the method further comprises representing a test audio signal with the expected listening environment, wherein the test signal is selected from broadband noise and frequency sweeps; Detecting an audio representation abnormality associated with the expected listening environment from a response resulting from the test audio signal, wherein the abnormality is detected using a device selected from a fast Fourier analyzer and a computer frequency analyzer; Analyzing a result from the detection device to determine a frequency associated with the anomaly of the audio signal; Adjusting the amplitude at the frequency to compensate for the anomaly using the multiband equalizer; And hard programming the adjustment operation at the frequency with one or more multi-band equalizers.

1 illustrates an exemplary embodiment of an equalizer, a compressor, and a mirror equalizer connected together.

2 illustrates an equalizer, a compressor, and a mirror equalizer connected together, in which the equalizer performs an amplification and attenuation operation in contrast to the equalizer of FIG. 1.

3 is a view showing in detail one example in accordance with an embodiment of the present invention.

4 is a diagram illustrating an equalizer, a compressor, and a mirror equalizer connected to a speaker.

5 is a diagram illustrating an equalizer, a mirror equalizer and a multi-band equalizer connected together in succession.

6 shows an equalizer, a compressor, a mirror compressor and an amplifier connected together in series.

7 is a diagram illustrating a process of detecting an abnormal phenomenon, determining a frequency at which an abnormal phenomenon occurs, and adjusting an amplitude at this frequency.

8 shows an equalizer, a compressor, a mirror equalizer, and a final equalizer connected together.

9 illustrates an equalizer, a compressor, a mirror equalizer, a final equalizer, an amplifier, a multi-band equalizer, and a speaker connected together.

The following description is intended to enable those skilled in the art to use the invention, and includes specific application examples and essential components. It will be apparent to those skilled in the art that various changes can be made to the appended embodiments, and the general concepts defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the following embodiments, but includes a wide range including the concepts and features included below.

The systems, methods and circuits described herein range from a wide dynamic range to a narrow dynamic range, and are designed to allow for the conversion of audio signals without distorting or altering the original work, and are also designed to compensate for environmental factors. Such systems are particularly suitable for playing music, movies or video games in high-noise environments (cars, airplanes, boats, clubs, theaters, amusement parks, shopping centers, etc.). Further, the systems, methods, and circuits of the present invention are intended to enhance sound representation by processing human audio and audio signals outside the effective range of audio converters between about 600 Hz and 1000 Hz. By processing this range of audio, a more complete and wider representation is possible.

Referring to the drawings, FIG. 1 is a diagram illustrating an embodiment of the present invention. The system includes a primary equalizer 20, a compressor 30 and a mirror equalizer 40. A schematic representation of the functionality of each individual component is shown in each figure. The audio input signal 10 is input to the primary equalizer 20 and an enhanced audio output signal 50 is generated from the mirror equalizer 40. The primary equalizer 20 of this embodiment receives the audio input signal 10, attenuates the amplitude of a portion of the signal corresponding to the bass spectrum of the sound, and adjusts the amplitude of the signal corresponding to the treble spectrum of the sound. Amplify. For example, the low audible bass portion (about 100 Hz) may be reduced by about 10 dB, and the high audible treble portion (about 8 kHz) may be reduced by about 8 dB, with the portions being adjusted as a linear function of frequency. Variations of suitable equalizers are known in the art. One such analog equalizer is shown in block 11 of FIG. 3.

At some frequencies between high and low frequency attenuation, the effects of amplification and attenuation intersect at the intersection points. At this intersection point, the effects of these two processes on the audio signal exactly cancel each other out and produce zero net gain. The frequency range where these two processes substantially nullify the effect on the audio signal is concentrated around this intersection point. In one embodiment of the invention, this range is between about 600 Hz and about 1000 Hz. In this embodiment, the crossing range is specifically designed to be included within the effective range of a standard acoustic transducer and the hearing of a person. Other embodiments may move this intersection point as needed for a particular application.

Referring back to FIG. 1, the primary equalizer 20 supplies a signal to the compressor 30. The compressor amplifies and attenuates the signal so that it is inversely proportional to the amplitude of the signal. That is, low amplitudes generate high amplification (or low attenuation), while high frequencies generate high compression (or low amplification). This results in a signal of low dynamic range. For example, the dynamic range of the signal can be lowered to 10 dB or less. Further, in another embodiment of the present invention, the compressor may attenuate the high amplitude of the audio signal above the low amplitude. In another embodiment, the low amplitude of the audio signal may be amplified above the high amplitudes. Modifications of suitable compressors are known in the art. One embodiment of a compressor is shown in block 12 of FIG. 3.

Referring again to FIG. 1, after compression, the audio signal is input to the mirror equalizer 40. This mirror equalizer 40 provides functionality that contrasts with the primary equalizer 20. Here, ie in this particular embodiment, the mirror equalizer increases the amplitude of the portion of the signal corresponding to the bass spectrum of the sound, and attenuates the amplitude of the signal corresponding to the high frequency spectrum of the sound. This mirror equalizer 40 has substantially the same intersection point as the primary equalizer 20. For example, the low audible bass portion (about 100 Hz) increases by about 10 dB, the high audible treble portion (about 8 kHz) attenuates by about 8 dB, and the portions between them are linearly adjusted as a function of frequency. The primary equalizer 10 and the mirror equalizer 30 are ideally selected to be complementary, having the same and opposite effects. One embodiment of a mirror equalizer is shown in block 13 of FIG. 3.

After primary equalization, compression, and mirror equalization, the processed audio signal is directly applied to the speaker system, and input into the speaker system through a multi-band equalizer or through the amplifier to the speaker system. Since the bass portion is reduced before compression and enhanced after compression, the sound provided to the speaker has a rich spectrum in the bass tones and can be free from the muffling effects that occur in normal compression. This embodiment can also produce rich sound even from small speaker systems (e.g., systems with magnets smaller than 10oz). Furthermore. Since the dynamic range is reduced by compression, sound is provided within the limited volume range. For example, in a high-noise environment with an 80 dB noise floor and an acoustic threshold of 110 dB, such a system comfortably provides high quality sound.

2 shows another embodiment of the present invention. This embodiment is similar to the embodiment shown in FIG. In this example, the primary equalizer 20 receives the audio input signal 10, amplifies the amplitude of a portion of the signal corresponding to the bass spectrum of the sound, and reduces the amplitude of the signal corresponding to the high frequency spectrum of the sound. do. The embodiment of FIG. 2 amplifies the signal in the region where the embodiment of FIG. Similarly, the embodiment of FIG. 2 attenuates the signal in the region where the embodiment of FIG. 1 amplifies. The mirror equalizer of FIG. 4 has a function opposite to that of the mirror equalizer of FIG. 1.

3 depicts a particular embodiment of the present invention. This embodiment is implemented with analog components. The equalizer is shown in block 11, the compressor in block 12, the mirror equalizer in block 13, the selected power source in block 20, and the 10 channel equalizer in block 21. do. All of the components shown are standard commercial components. Each individual module may be implemented with other reasonable substitutes known in the art.

4 shows another embodiment of the present invention. 4 illustrates the embodiment of FIG. 1 connected to a speaker system 60.

5 shows another embodiment of the present invention. In this embodiment, the multi-phase equalizer 100 is connected to the mirror equalizer 40 before the audio signal is output 50. In a further embodiment of the invention, these signals are output from the multi-band equalizer 100 to a speaker system (not shown in the figure).

6 shows another embodiment of the present invention. In this embodiment, amplifier 110 is connected to mirror equalizer 40 prior to output 50. In a further embodiment of the invention, this signal is output from the amplifier 110 to a speaker system (not shown).

7 shows another embodiment of the present invention. In FIG. 7, an audio representation response 15 is introduced, and anomaly of the audio representation is detected by the process 70. It is shown in the diagram of the schematic representation process 70 of such a signal having an audio anomaly. Note that an abnormally large amplitude of the audio representation appears at frequency 71. Some signals exhibit a number of anomalies or no anomalies. For example, a particular listening environment may generate these anomalous audio responses (such as those generated from standing waves). For example, such standing waves often occur in narrow listening environments (such as cars). The length of the car is, for example, about 400 cycles long. In this environment, some standing waves are set at these frequencies or slightly lower frequencies. Standing waves produce amplified signals at frequencies that produce disturbing acoustic signals. 7 shows only one anomaly for simplicity. Thus, process 70 detects anomalous representation in the signal, such as a portion of the signal at a given frequency amplified according to the standing wave. Next, process 80 determines the frequency 81 at which this anomalous audio representation occurs. In the figure, frequency 81 represents the frequency at which the anomalous audio representation is generated in points on the graph. Once the frequency at which the anomalous representation occurs is determined, the amplitude of the signal at this frequency decreases as shown at 90. Note that in the functional indication within 90, the abnormally high amplitude is reduced, which compensates for anomalies in the audio representation. Cars of the same size, shape, and the same characteristics (eg, cars of the same model) may exhibit the same anomalies. In a further embodiment, the adjusting frequency and the adjusting amount are pre-aligned in the equalizer, thus reducing the abnormal response to future expressions in the listening environment. For example, in one model of the car, the frequency and amount of control of the abnormal response are pre-adjusted in the equalizer built into the car audio system to compensate for this acoustic anomaly.

8 illustrates an embodiment of the invention shown in FIG. 1 that includes a final equalizer 70 that adjusts the amplitude of an audio signal at a given frequency to be related to acoustic representation anomalies associated with an expected listening environment.

9 illustrates the embodiment of FIG. 8 including an amplifier 110 for audio amplification, a multi-band equalizer 100 for future fine-tuning, and a speaker system 60 for acoustic representation.

Embodiments of the present invention assume the assumption that most audio converters are valid between about 600 Hz and about 1000 Hz. Furthermore, human hearing is very effective within this range. Because of this effectiveness, the present invention allows most of the audio processing outside this range to improve the quality of the overall sound representation.

One embodiment of the present invention provides a system for processing an audio signal having a primary equalizer, a compressor, and a mirror equalizer. The primary equalizer produces an equalized audio signal by adjusting the amplitude of the low frequency portions of the audio signal corresponding to the audible bass sound and the amplitude of the high frequency portion of the audio signal corresponding to the audible high pitch sound in the opposite direction. This regulating action occurs on a substantially linear frequency function. The adjustment operation of the low frequency portion of the signal mentioned above and the adjustment operation in the opposite direction of the high frequency portion of the signal are crossed between the frequency ranges which produce a substantially negligible gain within this range. The point at which these adjustments intersect is the crossing point and produces zero gain. The range around this point is the crossing range. For example, such intersection points may occur between about 600 Hz and about 1,000 Hz. One embodiment may further include a compressor that compresses the dynamic range of the audio signal to produce a compressed audio signal by attenuating high amplitude signals, amplifying low amplitude signals, or a combination of both. The compressor can compress the dynamic range of the audio signal to more than about 10db. Finally, the mirror equalizer has an effect on the audio signal that is substantially the opposite of the primary equalizer. This mirror equalizer has substantially the same intersection point and range as the primary equalizer.

At the point of intersection, the effects of the two adjustments on the audio signal, both in the primary and mirror equalizers, exactly cancel each other out and produce zero net gain. These two adjustments are concentrated around this crossing point, where the crossing range of frequencies substantially negates the effect on the audio signal. This crossover range is between about 600 Hz and about 1000 Hz in one embodiment of the invention. In this embodiment, the crossover range can be specifically designed to be within the effective range of human hearing with the standard acoustic transducer. Other embodiments may move this intersection point as needed for a particular application.

In one particular embodiment of the system, the primary equalizer boosts the high frequency portion of the audio signal and attenuates the low frequency portion of the audio signal. The mirror equalizer performs the opposite operation. That is, it attenuates the high frequency portion of the audio signal and boosts the low frequency portion of the audio signal. In each equalizer, at the same frequency between high frequency boosting and low frequency attenuation operations, the effects of boosting and attenuation intersect at the intersection points.

In another particular embodiment of the system, the primary equalizer attenuates the high frequency portion of the audio signal and boosts the low frequency portion of the audio signal. The mirror equalizer does the opposite. That is, the high frequency portion of the audio signal is boosted and the low frequency portion of the audio signal is attenuated.

In another particular embodiment of the system, the first order equalizer and the mirror equalizer use one or more filters. The equalizer uses, for example, high band and low band filters. A filter operating in the high frequency portion of the audio signal in the primary equalizer produces the same or opposite effect on the audio signal as the filter in the mirror equalizer. That is, for example, if the low frequency filter in the primary equalizer attenuates the 10 db signal at 100 Hz, then the low frequency filter of the mirror equalizer boosts the 10 db signal at 100 Hz. Within these frequencies, the filters boost and attenuate as a substantially linear frequency function.

Another embodiment of the system includes a final equalizer. The final equalizer may, after equalization, adjust the amplitude of the audio signal at preset frequencies to relate to acoustic representation anomalies associated with the expected listening environment. These frequencies can be detected in advance and related to acoustical anomalies such as standing waves and the frequencies absorbed and absorbed. The adjustment frequency and amount performed are preset in this final equalizer to reduce any abnormal response. Therefore, in the environment where the final equalizer is prepared, the audio signal reproduced through the final equalizer may indicate a music member abnormality associated with the listening environment.

Another embodiment of the system may send an audio signal to the amplifier after first order equalization and compression and mirror equalization. The system can also send audio signals to a multiband equalizer for fine-tuning. The system can also send audio signals to the speaker. These three components can be implemented in any combination with or without each other.

Another embodiment of the present invention is an audio signal processing method having a first equalization step, a compression step, and a mirror equalization field. The first equalization step adjusts the amplitude of the low frequency portion of the audio signal in response to the audible bass sound, and adjusts the amplitude of the high frequency portion of the audio signal corresponding to the audible treble sound in opposite directions to produce an equalized audio signal. . This adjustment operation is made as a function of the frequency which is substantially linear. In this method, the adjusting operation of the low frequency portion of the above-mentioned signal and the adjusting operation in the opposite direction of the high frequency portion of the signal are crossed between the crossing ranges producing a substantially negligible gain within the crossing range. For example, it has a crossing range that occurs between approximately 600 Hz and 1,000 Hz. This method also includes a compression step. The compression step attenuates the high amplitude signal, amplifies the low amplitude signal, or combines them to compress the dynamic range of the audio signal to produce a compressed audio signal. In the method according to an embodiment of the present invention, the compressing step may compress the dynamic range of the audio signal to about 10 db or less. The final step of this method is the mirror equalization step, which has substantially the opposite effect as the primary equalization step. This mirror equalization step has substantially the same cross range as the primary equalization step.

In one particular embodiment of the invention, the first equalization step boosts the high frequency portion of the audio signal and attenuates the low frequency portion of the audio signal. The mirror equalization step works in reverse. That is, the high frequency portion of the audio signal is attenuated and the low frequency portion of the audio signal is boosted. In each equalization step, at a certain frequency between high frequency boosting and low frequency attenuation, the effects of the boosting and attenuation operations intersect at the crossing points and generate zero net gain.

In another particular embodiment of the present invention, the first equalization step attenuates the high frequency portion of the audio signal and boosts the low frequency portion of the audio signal. The mirror equalization step works in reverse. That is, it boosts the high frequency portion of the audio signal and attenuates the low frequency portion of the audio signal. This embodiment, selected according to a particular application, has an intersection point and an intersection range selected according to the particular application.

Another embodiment of the present invention includes a final equalization step, which, after the mirror equalization step, adjusts the amplitude of the audio signal at a predetermined frequency to be associated with the acoustic representation anomalies associated with the expected listening environment. This frequency has been detected beforehand to correlate with acoustic abnormalities. The frequency and amount of this adjustment operation are preset at this stage to reduce abnormal response. Therefore, the audio signal reproduced through this final stage can provide music without abnormalities in an environment in which the final equalization stage is prepared.

The method of the present invention may be performed by any number of processors. It may be executed by a computer, computer software, electrical circuit, electrical chip programmed to perform these steps or by other means of performing the described method.

In one method according to the invention, the first-order equalization and mirror equalization steps use one or more filters. Filters operating in the high frequency portion of the signal in the first and mirror equalization stages produce equal or opposite effects. That is, for example, when the high frequency filter boosts the 8 db signal at 8 kHz in the primary equalization step, the high frequency filter attenuates the 8 db signal at 8 kHz in the mirror equalization step. For example, if the high frequency filter attenuates the 8 db signal at 8 kHz in the first equalization step, the high frequency filter boosts the 8 db signal at 8 kHz in the mirror equalization step. For example, if the low frequency filter boosts the 10 db signal at 100 Hz in the first equalization step, the low frequency filter attenuates the 10 db signal at 100 kHz in the mirror equalization step. Finally, for example, if the low frequency filter attenuates the 10 db signal at 100 kHz in the first equalization step, the low frequency filter boosts the 10 db signal at 100 kHz in the mirror equalization step. Between these frequencies, the filter performs boost and attenuation operations as a function of the substantially linear frequency.

Another embodiment according to the invention is for an audio signal processing circuit comprising a primary equalizer, a compressor and a mirror equalizer. By adjusting the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and by adjusting the amplitude of the high frequency portion of the audio signal corresponding to the audible high pitch sound in the opposite direction, the primary equalizer generates an equalized signal. This adjustment operation is made as a function of the frequency which is substantially linear. In such a circuit, the above-described adjustment operation of the low frequency portion of the audio signal and the adjustment operation in the opposite direction of the high frequency portion of the audio signal intersect with each other between frequency ranges that produce a substantially negligible gain in this range. . The circuit further includes a compressor for generating a compressed audio signal by compressing the dynamic range of the audio signal by a high amplitude signal, amplifying the low amplitude signal, or a combination of both. The compressor in this circuit compresses the dynamic range of the audio signal, for example to about 10 db or less. Finally, the circuit of this embodiment includes a mirror equalizer that produces a substantially opposite effect to the primary equalizer and has substantially the same cross range as the primary equalizer.

The primary and mirror equalizers of this circuit have a matched crossing point and a matched crossing range. The effect of these two adjustments on the audio signal at the intersection point exactly cancels each other out, resulting in zero net gain. The intersection range is concentrated around the intersection point. This crossing range, in one embodiment of the invention, is between about 600 Hz and 1,000 Hz. In this embodiment, the crossover range is specifically designed to be within the effective range of the standard acoustic transducer and human hearing. Other embodiments may move this intersection point as needed for a particular application.

In a particular embodiment of the invention, the primary equalizer boosts the high frequency portion of the audio signal and attenuates the low frequency portion of the audio signal. Mirror equalizers work the opposite way. That is, the high frequency portion of the audio signal is attenuated and the low frequency portion of the audio signal is boosted. In each equalizer, the effects of boosting and attenuation intersect with each other at the intersection points at some frequencies between high frequency boosting and low frequency attenuation and boosting.

In another embodiment of the present invention, the primary equalizer attenuates the high frequency portion of the audio signal and boosts the low frequency portion of the audio signal. Mirror equalizers work in reverse. That is, the high frequency portion of the audio signal is boosted and the low frequency portion of the audio signal is attenuated. In each equalizer, at some frequencies between high frequency boosting or attenuation and low frequency boosting or attenuation, the two processes intersect each other at the intersection point.

The circuit of the present invention may comprise a final equalizer. The final equalizer, after mirror equalization, adjusts the amplitude of the audio signal at a preset frequency to be related to the acoustic representation anomalies associated with the expected listening environment. These frequencies have been detected beforehand to correlate with acoustic abnormalities and are hard programmed into this circuit. The frequency and amount of adjustments performed is pre-fitted to this final equalizer to reduce any abnormal response. Therefore, the audio signal reproduced through this final equalizer may exhibit a musical component abnormality related to the clarity environment in the environment where the final equalizer is prepared.

The circuit according to the embodiment of the present invention may be implemented as a digital circuit, an analog circuit, or a combination thereof. Some of these circuits, ie equalizers or compressors, may be digital or analog and may be connected to each other. Various compressors and equalizer circuits that can be implemented to produce the requested results are known to those skilled in the art.

In the circuit of the present invention, the first-order equalizer and the mirror equalizer use one or more filters. In the primary and mirror equalizers, filters operating in the high frequency portion of the signal produce equal or opposite effects. That is, for example, when the high frequency filter of the primary equalizer boosts the 8 db signal at 8 kHz, the high frequency filter of the mirror equalizer attenuates the 8 db signal at 8 kHz. For example, if the high frequency filter of the primary equalizer attenuates the 8 db signal at 8 kHz, the high frequency filter of the mirror equalizer boosts the 8 db signal at 8 kHz. For example, if the low frequency filter of the primary equalizer boosts the 10 db signal at 100 Hz, the low frequency filter of the mirror equalizer attenuates the 10 db signal at 100 kHz. Finally, for example, if the low frequency filter of the primary equalizer attenuates the 10 db signal at 100 kHz, the low frequency filter of the equalizer boosts the 10 db signal at 100 kHz. Between these frequencies, the filter performs boost and attenuation operations as a function of the substantially linear frequency.

In another embodiment according to the present invention, this circuit may provide the audio signal to the amplifier after the first equalization and the compression and mirror equalization. The circuit also sends the audio signal to a multi-phase equalizer for fine-tuning. The system can also send audio signals to the speaker. These three components may be implemented in any combination with or without each other.

A further embodiment of the present invention relates to a hard-programming adjustment method with a multi-band equalizer that compensates for anomalies associated with an expected listening environment. This method includes a plurality of steps. The first step is to provide a test audio signal to the expected listening environment. This test audio signal may be broadband noise, frequency sweep or other test signal known in the art. The test audio signal may be well known music and represents an interpreted response. The next step of this method is to detect audio representation anomalies associated with the expected listening environment in the response from the test audio signal. This step can be performed using a fast Fourier analyzer and a computer frequency analyzer or other system that interprets the amplitude response of the audio signal over a wide range of frequencies. By analyzing the response returned by the listening environment, it is possible to determine the frequency at which standing waves occur in the environment, the frequency accentuated by the environment, the frequency absorbed by the environment, or the remaining types of abnormal response depending on the presentation environment. Once the frequency of the anomaly and the magnitude (amount) of the anomaly are known, the multiband equalizer is adjusted to compensate for this anomaly. Finally, the amount of this adjustment operation at the set frequency is hard programmed into the multiband equalizer or a set of multiband equalizers. These values are stored in some storage device or physically set. Thus, by using a multi-band equalizer in a system used in an expected listening environment or similar environment, music can be provided regardless of environmental abnormalities.

For example, certain embodiments of the present invention may include developing a hard-programmed multi-band equalizer using an adjustment operation that compensates for anomalies associated with a model vehicle. Individual cars of the same model are likely to exhibit very similar listening anomalies depending on similar size, shape, structural arrangement, speaker placement, speaker quality, and speaker size. While in the interior of an auto of a model, by reproducing the test signal through the automotive acoustic system, the user can implement the method according to this embodiment. While this test signal is being reproduced, a computer using hardware and frequency response software such as fast Fourier analysis software can detect an abnormal response of the environment to the test signal. The system can detect standing waves due to the small size of the vehicle, detect frequencies that are emphasized or absorbed by the material inside the vehicle, or detect diffraction phenomena affected by the shape of the vehicle. When such anomalies are detected, the frequency and magnitude of the anomaly are recognized and an appropriate amount of adjustment operation is made within the multi-band equalizer at this frequency. This method is repeated until the environment related to the abnormal phenomenon is reasonably adjusted. The amount of adjustment at each frequency appears with frequency. These values are hard programmed into the equalizer and implemented in car audio systems of the same model. According to this method, each vehicle may have an audio system that provides sound without abnormalities.

The above-described embodiments of the present invention are for illustration and description only, and are not intended to limit the present invention to the described form. Accordingly, various changes and modifications can be made to those skilled in the art to which the present invention pertains. In addition, the detailed description of this specification does not limit the scope of the present invention. The scope of the invention is defined by the appended claims.

Claims (26)

A primary equalizer for generating an equalized audio signal by adjusting an amplitude of a low frequency portion of an audio signal corresponding to an audible bass sound and adjusting an amplitude of the high frequency portion of the audio signal corresponding to an audible high pitch sound in an opposite direction, The primary equalizer crossing each other between the adjusting range and the crossing range of frequencies where the adjusting operation in the opposite direction produces a negligible gain in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; And And a mirror equalizer which produces an effect opposite to the first equalizer. The method of claim 1, And said crossing range is between 600 Hz and 1,000 Hz. The method of claim 1, And the primary equalizer and the mirror equalizer adjust the amplitude according to a linear frequency function. The method of claim 1, And the compressor compresses the audio signal by attenuating a high amplitude portion of the audio signal. The method of claim 1, And the compressor compresses the audio signal by amplifying the low amplitude portion of the audio signal. The method of claim 1, The primary equalizer uses one or more filters to adjust the amplitude of the high frequency portion of the audio signal, and the mirror equalizer uses one or more filters to act as opposed to the primary equalizer on the high frequency portion of the audio signal. Add, And the filter has the same and opposite action on the audio signal. The method of claim 1, The primary equalizer uses one or more filters to adjust the amplitude of the low frequency portion of the audio signal, and the mirror equalizer uses one or more filters to effect the opposite effect of the primary equalizer on the low frequency portion of the audio signal. But And said filters apply the same and opposite action to said audio signal. The method of claim 1, And a speaker system responsive to an equalized output signal of said mirror equalizer. The method of claim 1, The compressor compresses the dynamic range of the audio signal to about 10 dB or less. The method of claim 1, And the first equalizer reduces the amplitude of the low frequency portion of the signal by 10 dB at 100 Hz. The method of claim 1, And the first equalizer increases the amplitude of the high frequency portion of the signal by 8 dB at 8 kHz. The method of claim 1, And the mirror equalizer increases the amplitude of the low frequency portion of the signal by 10 dB at 100 Hz. The method of claim 1, The mirror equalizer reduces the amplitude of the high frequency portion of the signal by 8 dB at 8 kHz. The method of claim 1, And the first equalizer increases the amplitude of the low frequency portion of the signal by 10 dB at 100 Hz. The method of claim 1, And said first equalizer reduces the amplitude of the high frequency portion of said signal by 8 dB at 8 kHz. The method of claim 1, And the mirror equalizer reduces the amplitude of the low frequency portion of the signal by 10 dB at 100 Hz. The method of claim 1, The mirror equalizer increases the amplitude of the high frequency portion of the signal by 8 dB at 8 kHz. A primary equalizer for reducing the amplitude of the low frequency portion of an audio signal corresponding to an audible bass sound and increasing the amplitude of the high frequency portion of the audio signal corresponding to an audible high pitch sound, thereby generating an equalized audio signal. The primary equalizer crossing each other between the crossing ranges where the increase produces negligible gain in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; And Mirror equalizer that produces the opposite effect to the primary equalizer Audio signal processing system comprising a. A primary equalizer for generating an equalized audio signal by adjusting an amplitude of a low frequency portion of an audio signal corresponding to an audible bass sound and adjusting an amplitude of the high frequency portion of the audio signal corresponding to an audible high pitch sound in an opposite direction, The primary equalizer crossing each other between the adjusting range and the crossing range of frequencies where the adjusting operation in the opposite direction produces a negligible gain in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; A mirror equalizer which produces an effect opposite to the primary equalizer; And Final equalizer that adjusts the amplitude of the signal at preset frequencies to be related to acoustic representation anomalies associated with the expected listening environment Audio signal processing system comprising a. A primary equalizer for reducing the amplitude of the low frequency portion of an audio signal corresponding to an audible bass sound and increasing the amplitude of the high frequency portion of the audio signal corresponding to an audible high pitch sound, thereby generating an equalized audio signal. The primary equalizer crossing each other between the crossing ranges where the increase produces negligible gain in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; A mirror equalizer which produces an effect opposite to the primary equalizer; And Final equalizer that adjusts the amplitude of the signal at preset frequencies to be related to acoustic representation anomalies associated with the expected listening environment Audio signal processing system comprising a. Adjusting the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and firstly equalizing the audio signal by adjusting the amplitude of the high frequency portion of the audio signal corresponding to the audible treble sound in the opposite direction, wherein The first equalization step intersecting each other between the adjustment operation and the intersection range of frequencies where the adjustment operation in the opposite direction produces negligible gain in the intersection range; Compressing a dynamic range of the audio signal; And Mirror equalizing the audio signal in a manner opposite to the first equalization step Audio signal processing method comprising a. Adjusting the amplitude of the low frequency portion of the audio signal corresponding to the audible bass sound and firstly equalizing the audio signal by adjusting the amplitude of the high frequency portion of the audio signal corresponding to the audible treble sound in the opposite direction, wherein The first equalization step intersecting each other between the adjustment operation and the intersection range of frequencies where the adjustment operation in the opposite direction produces negligible gain in the intersection range; Compressing a dynamic range of the audio signal; Mirror equalizing the audio signal in a manner opposite to the first equalization step; And Adjusting the amplitude of the signal at a preset frequency to be related to acoustic representation anomalies associated with an expected listening environment Audio signal processing method comprising a. A primary equalizer for generating an equalized audio signal by adjusting an amplitude of a low frequency portion of an audio signal corresponding to an audible bass sound and adjusting an amplitude of the high frequency portion of the audio signal corresponding to an audible high pitch sound in an opposite direction, The primary equalizer crossing each other between the adjusting range and the crossing range of frequencies where the adjusting operation in the opposite direction produces a negligible gain in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; And Mirror equalizer that produces the opposite effect to the primary equalizer Audio signal processing circuit comprising a. A primary equalizer for generating an equalized audio signal by adjusting an amplitude of a low frequency portion of an audio signal corresponding to an audible bass sound and adjusting an amplitude of the high frequency portion of the audio signal corresponding to an audible high pitch sound in an opposite direction, The primary equalizer crossing each other between the adjusting range and the crossing range of frequencies where the adjusting operation in the opposite direction produces a negligible gain in the crossing range; A compressor for generating a compressed audio signal by compressing a dynamic range of the audio signal; A mirror equalizer which produces an effect opposite to the primary equalizer; And Final equalizer that adjusts the amplitude of the signal at preset frequencies to be related to acoustic representation anomalies associated with the expected listening environment Audio signal processing circuit comprising a. A method of hard-programming an adjustment operation to one or more multi-band equalizers that compensates for anomalies associated with an expected listening environment, the hard program method comprising: Representing a test audio signal with the expected listening environment; Detecting an audio representation anomaly associated with the expected listening environment from a response resulting from the test audio signal; Determining a frequency associated with the anomaly of the audio signal; In the multiband equalizer, adjusting an amplitude at the frequency to compensate for the anomaly; And Hard programming the adjustment operation at the frequency with one or more multi-band equalizers Hard program method comprising a. A method of hard-programming an adjustment operation to one or more multi-band equalizers that compensates for anomalies associated with an expected listening environment, the hard program method comprising: Representing a test audio signal in the expected listening environment, wherein the test signal is selected from wideband noise and frequency sweep; Detecting an audio representation abnormality associated with the expected listening environment from a response resulting from the test audio signal, wherein the abnormality is detected using a device selected from a fast Fourier analyzer and a computer frequency analyzer; Analyzing a result from the detection device to determine a frequency associated with the anomaly of the audio signal; Adjusting the amplitude at the frequency to compensate for the anomaly using the multiband equalizer; And Hard programming the adjustment operation at the frequency with one or more multi-band equalizers Hard program method comprising a.

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