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EP1779509A2 - Systeme et procede de traitement des signaux audio pour presentation dans un environnement a bruit eleve - Google Patents

Systeme et procede de traitement des signaux audio pour presentation dans un environnement a bruit eleve

Info

Publication number
EP1779509A2
EP1779509A2 EP05776404A EP05776404A EP1779509A2 EP 1779509 A2 EP1779509 A2 EP 1779509A2 EP 05776404 A EP05776404 A EP 05776404A EP 05776404 A EP05776404 A EP 05776404A EP 1779509 A2 EP1779509 A2 EP 1779509A2
Authority
EP
European Patent Office
Prior art keywords
audio signal
equalizer
amplitude
adjusting
primary
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP05776404A
Other languages
German (de)
English (en)
Other versions
EP1779509A4 (fr
Inventor
Anthony Bongiovi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US10/914,234 external-priority patent/US7254243B2/en
Application filed by Individual filed Critical Individual
Publication of EP1779509A2 publication Critical patent/EP1779509A2/fr
Publication of EP1779509A4 publication Critical patent/EP1779509A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G9/00—Combinations of two or more types of control, e.g. gain control and tone control
    • H03G9/02—Combinations of two or more types of control, e.g. gain control and tone control in untuned amplifiers
    • H03G9/12—Combinations of two or more types of control, e.g. gain control and tone control in untuned amplifiers having semiconductor devices
    • H03G9/18—Combinations of two or more types of control, e.g. gain control and tone control in untuned amplifiers having semiconductor devices for tone control and volume expansion or compression
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G7/00—Volume compression or expansion in amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G9/00—Combinations of two or more types of control, e.g. gain control and tone control
    • H03G9/005—Combinations of two or more types of control, e.g. gain control and tone control of digital or coded signals

Definitions

  • the present invention relates to novel systems, methods, and circuits useful for achieving quality sound presentation in high-noise environments. Specifically, the present invention provides systems, methods, and circuits for processing audio signals. The present invention further provides methods for hard-programming adjustments into a multi-band equalizer that compensates for anomalies associated with an anticipated listening environment.
  • bass response of a system in such an environment is generally inadequate. While the bass response may be boosted with an equalizer to compensate for this inadequacy, this approach typically causes a muffled treble response, thus diminishing the sound quality. In addition to a muffled treble, bass boosting may undesirably increase the dynamic range of the sound presentation. In a noisy environment, there is very little audio range between the volume floor set by the noise (typically around 80 dB in moving vehicles) and the volume ceiling set by the physiology of the ear (typically around 1 10 dB).
  • Increasing the dynamic range of sound presented in a noisy environment may be aesthetically undesirable because the sound level may approach the ear's physiological volume ceiling, resulting in an unpleasant, annoying, or even painful response. Accordingly, a new approach is needed for quality audio presentation in a high- noise environment.
  • Typical consumer sound transducers such as commercial speakers, are acoustically efficient between approximately 600 and 1,000 cycles. To compensate for the inefficient performance of such transducers outside this range, systems often employ a variety of special speakers and amplifiers that can be quite expensive. A system that compensates for this inefficient performance without the introduction of extra and often expensive hardware would be beneficial.
  • the present invention relates to novel systems, methods, and circuits useful for achieving quality sound presentation in high-noise environments.
  • the present invention provides systems for processing an audio signal.
  • the system may comprise a primary equalizer that produces an equalized audio signal by adjusting the amplitude of the low frequency portions of the audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of the audio signal corresponding to audible treble sounds, wherein the adjusting and the adjusting in the opposite direction intersect between a crossover range of frequencies producing a substantially negligible gain in the crossover range; a compressor that produces a compressed audio signal by compressing the dynamic range of the audio signal; and a mirror equalizer that produces a substantially opposite effect as the primary equalizer.
  • the system may comprise a primary equalizer that produces an equalized audio signal by decreasing the amplitude of the low frequency portions of the audio signal corresponding to audible bass sounds and increasing the amplitude of the high frequency portions of the audio signal corresponding to audible treble sounds, wherein the decreasing and the increasing intersect between a frequency range producing a substantially negligible gain in the range; a compressor that produces a compressed audio signal by compressing the dynamic range of the audio signal; and a mirror equalizer that produces a substantially opposite effect as the primary equalizer.
  • the system may comprise a primary equalizer that produces an equalized audio signal by adjusting the amplitude of the low frequency portions of the audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of the audio signal corresponding to audible treble sounds, wherein the adjusting and the adjusting in the opposite direction intersect between a frequency range producing a substantially negligible gain in the range; a compressor that produces a compressed audio signal by compressing the dynamic range of the audio signal; a mirror equalizer that produces a substantially opposite effect as the primary equalizer; and a final equalizer that adjusts the amplitude of the signal at frequencies predetermined to be related to sound presentation anomalies associated with the anticipated listening environment.
  • a primary equalizer that produces an equalized audio signal by adjusting the amplitude of the low frequency portions of the audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of the audio signal corresponding to audible treble sounds, wherein the adjusting and the adjusting
  • the system may comprise a primary equalizer that produces an equalized audio signal by decreasing the amplitude of the low frequency portions of the audio signal corresponding to audible bass sounds and increasing the amplitude of the high frequency portions of the audio signal corresponding to audible treble sounds, wherein the decreasing and the increasing intersect between a frequency range producing a substantially negligible gain in the range; a compressor that produces a compressed audio signal by compressing the dynamic range of the audio signal; a mirror equalizer that produces a substantially opposite effect as the primary equalizer; and a final equalizer that adjusts the amplitude of the signal at frequencies predetermined to be related to sound presentation anomalies associated with the anticipated listening environment.
  • the systems of the present invention may further comprise a speaker system responsive to the output signal of the mirror equalizer.
  • the crossover range may be approximately 600 Hz to approximately 1 ,000 Hz.
  • the primary equalizer and the mirror equalizer may adjust amplitude according to a substantially linear function of frequency.
  • the compressor may compress the audio signal by attenuating the high amplitude portions of the audio signal.
  • the compressor may compress the audio signal by amplifying the low amplitude portions of the audio signal.
  • the compressor may compress the dynamic range of the audio signal to less than about 1O dB.
  • the primary equalizer may use at least one filter to adjust the amplitude of the high frequency portions of the audio signal and the mirror equalizer may use at least one filter to produce a substantially opposite effect on the high frequency portions of the audio signal as the primary equalizer; wherein ' the filters may have a substantially equal and opposite effect on the audio signal.
  • the primary equalizer may use at least one filter to adjust the amplitude of the low frequency portions of the audio signal and the mirror equalizer may use at least one filter to produce a substantially opposite effect on the low frequency portions of the audio signal as the primary equalizer; wherein the filters may have an equal and opposite effect on the audio signal.
  • the primary equalizer may decrease the amplitude of the low frequency portions of the signal by about 10 dB at 100 Hz. In another embodiment, the primary equalizer may increase the amplitude of the high frequency portions of the signal by about 8 dB at 8 kHz.
  • the primary equalizer may increase the amplitude of the low frequency portions of the signal by about 10 dB at 100 Hz. Alternatively, the primary equalizer may decrease the amplitude of the high frequency portions of the signal by about 8 dB at 8 kHz.
  • the mirror equalizer may increase the amplitude of the low frequency portions of the signal by about 10 dB at 100 Hz. In a further embodiment, the mirror equalizer may decrease the amplitude of the high frequency portions of the signal by about 8 dB at 8 kHz.
  • the mirror equalizer may decrease the amplitude of the low frequency portions of the signal by about 10 dB at 100 Hz.
  • the mirror equalizer may increase the amplitude of the high frequency portions of the signal by about 8 dB at 8 kHz.
  • the present invention provides methods for processing an audio signal.
  • the method may comprise primary equalizing the audio signal by adjusting the amplitude of the low frequency portions of the audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of the audio signal corresponding to audible treble sounds, wherein the adjusting and the adjusting in the opposite direction intersect between a frequency range producing a substantially negligible gain in the range; compressing the dynamic range of the audio signal; and mirror equalizing the audio signal in a substantially opposite way as the primary equalizing.
  • the method may comprise primary equalizing the audio signal by adjusting the amplitude of the low frequency portions of the audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of the audio signal corresponding to audible treble sounds, wherein the adjusting and the adjusting in the opposite direction intersect between a frequency range producing a substantially negligible gain in the range; compressing the dynamic range of the audio signal; mirror equalizing the audio signal in a substantially opposite way as the primary equalizing; and adjusting the amplitude of the signal at frequencies predete ⁇ nined to be related to sound presentation anomalies associated with the anticipated listening environment.
  • the present invention provides circuits for processing an audio signal.
  • the circuit may comprise a primary equalizer that produces an equalized audio signal by adjusting the amplitude of the low frequency portions of the audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of the audio signal corresponding to audible treble sounds, wherein the adjusting and the adjusting in the opposite direction intersect between a frequency range producing a substantially negligible gain in the range; a compressor that produces a compressed audio signal by compressing the dynamic range of the audio signal; and a mirror equalizer that produces a substantially opposite effect as the primary equalizer.
  • the circuit may comprise a primary equalizer that produces an equalized audio signal by adjusting the amplitude of the low frequency portions of the audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of the audio signal corresponding to audible treble sounds, wherein the adjusting and the adjusting in the opposite direction intersect between a frequency range producing a substantially negligible gain in the range; a compressor that produces a compressed audio signal by compressing the dynamic range of the audio signal; a mirror equalizer that produces a substantially opposite effect as the primary equalizer; and a final equalizer that adjusts the amplitude of the signal at frequencies predetermined to be related to sound presentation anomalies associated with the anticipated listening environment.
  • a primary equalizer that produces an equalized audio signal by adjusting the amplitude of the low frequency portions of the audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of the audio signal corresponding to audible treble sounds, wherein the adjusting and the adjusting
  • the present invention provides methods for hard-programming adjustments into at least one multi-band equalizer that compensates for anomalies associated with an anticipated listening environment.
  • the method may comprise presenting a test audio signal into the anticipated listening environment; detecting audio presentation anomalies associated with the anticipated listening environment from responses from the test audio signal; determining the frequency associated with the anomalies of the audio signal; adjusting the amplitude at the frequency to compensate for the anomalies in the multi-band equalizer; and hard-programming the adjustment at the frequency into at least one multi-band equalizer.
  • the method may comprise presenting a test audio signal into the anticipated listening environment, wherein the test audio signal is selected from the group consisting of broadband noise and frequency sweeps; detecting audio presentation anomalies associated with the anticipated listening environment from responses from the test audio signal, wherein the anomalies are detected with a device selected from the group consisting of a fast Fourier analyzer and a computer frequency analyzer; determining the frequency associated with the anomalies of the audio signal by analyzing the results of from the detecting device; adjusting the amplitude at the frequency with the multi-band equalizer to compensate for the anomalies; and hard-programming the adjustment at the frequency into the multi-band equalizer.
  • FIG. 1 is a schematic view of and example system in which the equalizer, compressor, and mirror equalizer are coupled together.
  • FIG. 2 is a schematic view of the equalizer, compressor, and mirror equalizer coupled together, where the equalizers amplify and attenuate opposite to those of FIG. 1.
  • FIG. 3 is a detailed schematic of one example of one embodiment of the present invention.
  • FIG. 4 is a schematic view of an equalizer, compressor, and mirror equalizer coupled with a speaker.
  • FIG. 5 is a schematic view of an equalizer, compressor, mirror equalizer and a multi- band equalizer sequentially coupled together.
  • FIG. 6 is a schematic view of an equalizer, compressor, mirror equalizer and an amplifier sequentially coupled together.
  • FIG. 7 is a schematic view of the process of detecting anomalies, determining the frequency where the anomaly occurs, and then adjusting amplitude at that frequency.
  • FIG. 8 is a schematic view of an equalizer, compressor, mirror equalizer, and final equalizer coupled together.
  • FIG. 9 is a schematic view of an equalizer, compressor, mirror equalizer, final equalizer, amplifier, a multi-band equalizer, and a speaker coupled together.
  • a reference to “a step” or “a means” is a reference to one or more steps or means and may include sub-steps and subservient means. All conjunctions used are to be understood in the most inclusive sense possible. Thus, the word “or” should be understood as having the definition of a logical “or” rather than that of a logical “exclusive or” unless the context clearly necessitates otherwise. Language that may be construed to express approximation should be so understood unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs.
  • the system, methods, and circuitry described herein are designed to accommodate the conversion of audio signals with a broad dynamic range to a narrow dynamic range without distorting or altering the original work and to compensate for environmental factors.
  • This system is particularly suited for playing music, movies, or video games in high-noise environments such as an automobile, airplane, boat, club, theatre, amusement park, shopping center, etc.
  • the system, methods, and circuitry of the present invention seek to improve sound presentation by processing an audio signal outside the efficiency range of both the human ear and audio transducers which is between approximately 600 Hz and approximately 1 ,000 Hz. By processing audio outside this range, a fuller and broader presentation may be obtained.
  • FIG. 1 is a schematic view of one embodiment of the present invention.
  • the system comprises a primary equalizer 20, a compressor 30, and a mirror equalizer 40.
  • a graphical representation of the functionality of each individual component is shown within the drawing of each.
  • An audio input signal 10 is inputted into the primary equalizer 20 and an enhanced audio output signal 50 is produced from the mirror equalizer 40.
  • the primary equalizer 20 in this embodiment receives an audio input signal 10, attenuates the amplitude of the portion of the signal corresponding to the bass spectrum of sound, and amplifies the amplitude of the signal corresponding to the treble spectrum of sound.
  • the low audible bass portion (around 100 Hz) may be decreased by about 10 dB
  • the high audible treble portion (around 8 kHz) may be increased by about 8 dB
  • the portions in between are adjusted as a linear function of frequency.
  • a variety of suitable equalizers are known in the art. One such analog equalizer is shown in block 1 1 of FIG. 3.
  • this crossover point At some frequency between this high frequency amplification and low frequency attenuation the effects of the amplification and attenuation intersect at the crossover point. At this crossover point, the effect of these two processes on the audio signal exactly cancel each other out and produce a net gain of zero. Centered around this crossover point is a range of frequencies where these two processes substantially negate their effect on the audio signal. In one embodiment of the present invention, this range is between approximately 600 Hz and approximately 1,000 Hz. In this embodiment, the crossover range is specially designed to be within the efficiency range of standard sound transducers and the human ear. Other embodiments may shift this crossover point as necessitated by the specific application.
  • the primary equalizer 20 feeds the compressor 30.
  • the compressor amplifies and attenuates the signal inversely proportional to the amplitude of the signal. That is, low amplitudes are provided high amplification (or low attenuation) while high amplitudes are provided high compression (or low amplification). This results in a lower dynamic range of the signal.
  • the dynamic range of the signal for example, may be lowered to as little as 10 dB or less.
  • the compressor may attenuate the high amplitudes of an audio signal more than low amplitudes.
  • the compressor may amplify low amplitudes of an audio signal more than high amplitudes.
  • a variety of suitable compressors are known in the art. One embodiment of a compressor is shown in block 12 of FIG. 3.
  • the audio signal is fed into the mirror equalizer 40.
  • This mirror equalizer 40 provides the opposite functionality as the primary equalizer 20.
  • the mirror equalizer increases the amplitude of the portion of the signal corresponding to the bass spectrum of sound and decreases the amplitude of the signal corresponding to the treble spectrum of sound.
  • This mirror equalizer 40 also has 1 a crossover point that is substantially the same crossover point as the primary equalizer 20.
  • the low audible bass portion around 100 Hz
  • the high audible treble portion around 8 kHz
  • the primary equalizer 10 and mirror equalizer 30 are ideally chosen to be complementary so that they have equal and opposite affects.
  • One embodiment of a mirror equalizer is shown in block 13 of FIG. 3.
  • the processed audio signal may be applied directly to a speaker system, through a multi-band equalizer to a speaker system, or through an amplifier to a speaker system.
  • the bass portion may be reduced before compression and enhanced after compression, the sound presented to the speakers has a spectrum rich in bass tones and free of the muffling effects encountered with conventional compression.
  • this embodiment produces a rich sound even from a small speaker system, for example, those having magnets less than 10 oz.
  • the dynamic range has been reduced by compression, the sound may be presented within a limited volume range. For example, this system may comfortably present quality sound in a high-noise environment with an 80 dB noise floor and a 1 10 dB sound threshold.
  • FIG. 2 shows another embodiment of the present invention. This embodiment is similar to that embodiment shown in FIG. 1.
  • the primary equalizer 20 receives an audio input signal 10, amplifies the amplitude of the portion of the signal corresponding to the bass spectrum of sound, and attenuates the amplitude of the signal corresponding to the treble spectrum of sound.
  • the embodiment of FlG. 2 amplifies the signal where the embodiment of FIG. 1 attenuates.
  • the embodiment of FIG. 2 attenuates the signal where the embodiment of FIG. 1 amplifies.
  • the mirror equalizer in FIG. 4 also has the opposite functionality of the mirror equalizer in FlG. 1.
  • FIG. 3 is a diagram of one specific embodiment of the present invention. This embodiment shows implemented with analog components.
  • the equalizer is shown in block 1 1 , the compressor in block 12, the mirror equalizer in block 13, an optional power supply is shown in block 20, and a 10 channel equalizer in block 21. All of the components shown are standard, commercially available components. Each individual module may be implemented with another reasonable substitute known in the art.
  • FIG. 4 represents another embodiment of the present invention.
  • FIG. 4 shows the embodiment of FIG. 1 coupled with a speaker system 60.
  • FIG. 5 represents another embodiment of the present invention.
  • a multi-phase equalizer 100 is coupled with a mirror equalizer 40 before the audio signal is output 50.
  • a signal outputs from the multi- band equalizer 100 to a speaker system that is not shown in the drawings.
  • FIG. 6 represents another embodiment of the present invention.
  • an amplifier 1 10 is coupled to the mirror equalizer 40 prior to output 50.
  • such a signal outputs from the amplifier 1 10 to a speaker system that is not shown in the drawing.
  • FIG. 7 represents another embodiment of the present invention.
  • an audio presentation response 15 is introduced and anomalies in the audio presentation are detected by process 70.
  • a graphical representation of such a signal with an audio anomaly is shown within the drawing of process 70. Note the extraordinarily large amplitude of the audio presentation at one frequency 71.
  • Some signals may present multiple or no anomalies. For example, a particular listening environment may produce such anomalous audio responses such as those from standing waves. For example, such standing waves often occur in small listening environments such as an automobile.
  • the length of an automobile for example, is around 400 cycles long. In such an environment, some standing waves are set up at this frequency and some below. Standing waves present an amplified signal at their frequency which may present an annoying acoustic signal.
  • the process 70 detects an anomalous presentation in a signal, such as a portion of a signal at a given frequency amplified due to a standing wave.
  • process 80 determines the frequency at which such an anomalous audio presentation occurs 81. In the drawing, 81 points to the point on the graph where the frequency at which the anomalous audio presentation occurs. Once the frequency at which an anomalous presentation occurs is determined, the amplitude of the signal at this frequency is then decreased as shown in 90.
  • the anomalously high amplitude is reduced, which compensates for anomalies in the audio presentation.
  • Automobiles of the same size, shape, and of the same characteristics, such as cars of the same model may present the same anomalies.
  • the frequency and amount of adjustment performed may be preset in an equalizer to reduce anomalous responses for future presentation in the listening environment.
  • the frequency and adjustment amount of anomalous responses in a model of an automobile may be preset in an equalizer that is implemented with the cars audio system to compensate for these acoustical anomalies.
  • FIG. 8 shows the embodiment of the invention shown in FIG. 1 with a final equalizer 70 that adjusts the amplitude of the audio signal at frequencies predetermined to be related to sound presentation anomalies associated with the anticipated listening environment.
  • FIG. 9 illustrates the embodiment of FIG. 8 with an amplifier 1 10 for audio amplification, a multi-band equalizer 100, for further fine-tuning, and a speaker system 60 for sound presentation.
  • the embodiments of the present invention are premised on the assumption that most audio transducers are efficient between about 600 Hz and about 1,000 Hz. Furthermore, the human ear is very efficient within this range. Because of these efficiencies, the present invention may do most of its audio processing outside of this range to improve the overall quality of the sound presentation.
  • One embodiment of the present invention provides for a system for processing an audio signal with a primary equalizer, compressor, and mirror equalizer.
  • the primary equalizer produces an equalized audio signal by adjusting the amplitude of the low frequency portions of an audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of an audio signal corresponding to audible treble sounds. These adjustments occur in a substantially linear function of frequency.
  • the above mentioned adjusting of the low frequency portions of the signal and the adjusting in the opposite direction of the high frequency portion of the signal intersect between a frequency range that produces a substantially negligible gain within this range.
  • the point where these adjustments intersect is the crossover point and produces a gain of zero.
  • the range around this point is the crossover range.
  • this crossover point may occur between about 600 Hz and about 1,000 Hz.
  • An embodiment may further comprise a compressor that produces a compressed audio signal by compressing the dynamic range of the audio signal by attenuating high amplitude signals, amplifying low amplitude signals, or by doing a combination of both.
  • the compressor may compress the dynamic range of the audio signal to less than about 10 db.
  • a mirror equalizer produces a substantially opposite effect on the audio signal as the primary equalizer. This mirror equalizer has substantially the same crossover point and range as the primary equalizer.
  • This crossover range is between approximately 600 Hz and approximately 1 ,000 Hz.
  • the crossover range may be specially designed to be within the efficiency range of standard sound transducers and the human ear. Other embodiments may shift this crossover point as necessitated by the specific application.
  • the primary equalizer boosts the high frequency portions of an audio signal and attenuates the low frequency portions of an audio signal.
  • the mirror equalizer does the opposite; it attenuates the high frequency portions of an audio signal and boosts the low frequency portions of an audio signal.
  • each equalizer at the same frequency between the high frequency boosting and low frequency attenuating and boosting, the effects of the boosting and attenuation intersect at the crossover point.
  • the primary equalizer attenuates the high frequency portions of an audio signal and boosts the low frequency portions of an audio signal.
  • the mirror equalizer does the opposite; it boosts the high frequency portions of an audio signal and attenuates the low frequency portions of an audio signal.
  • the primary equalizer and mirror equalizer use at least one filter.
  • the equalizers may, for example, use a high-band and a low- band filter.
  • the filter that operates on the high frequency portion of an audio signal in the primary equalizer produces an equal and opposite effect on the audio signal as the filter in the mirror equalizer. That is, for example, if the high frequency filter in the primary equalizer boosts the signal 8 db at 8 kHz, then the high frequency filter in the mirror equalizer attenuates the signal 8 db at 8 kHz.
  • the high frequency filter in the primary equalizer attenuates the signal 8 db at 8 kHz then the high frequency filter in the mirror equalizer boosts the signal 8 db at 8 kHz.
  • the low frequency filter in the primary equalizer boosts the signal 10 db at 100 Hz
  • the low frequency filter in the mirror equalizer attenuates the signal 10 db at 100 Hz.
  • the low frequency filter in the mirror equalizer boosts the signal 10 db at 100 Hz. In between these frequencies the filters boost and attenuate at a substantially linear function of frequency.
  • Another embodiment of the system includes a final equalizer which, after mirror equalization, may adjust the amplitude of the audio signal at frequencies predetermined to be related to sound presentation anomalies associated with the anticipated listening environment. These frequencies have been previously detected to be associated with acoustical anomalies such as standing waves, and accented and absorbed frequencies. The frequency and magnitude of adjustment performed may be preset in this final equalizer to reduce any anomalous responses. Thus, audio signals played through this final equalizer in environments in which the final equalizer was prepared may present music absent anomalies associated with the listening environment.
  • Another embodiment of the system may present an audio signal after primary equalization, compression, and mirror equalization to an amplifier.
  • the system may also present an audio signal to a multi-band equalizer for fine-tuning.
  • the system may also present an audio signal to a speaker.
  • Another embodiment of the present invention is a method for processing an audio signal with a primary equalizing step, a compression step, and a mirror equalizing step.
  • the primary equalizing step produces an equalized audio signal by adjusting the amplitude of the low frequency portions of an audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of an audio signal corresponding to audible treble sounds. These adjustments occur in a substantially linear function of frequency.
  • the above-mentioned adjusting of the low frequency portions of the signal and the adjusting in the opposite direction of the high frequency portion of the signal intersect between a crossover range that produce a substantially negligible gain within this crossover range.
  • one method may have a crossover range may occur between approximately 600 Hz and approximately 1 ,000 Hz.
  • This method further comprises a compressing step that produces a compressed audio signal by compressing the dynamic range of the audio signal by attenuating high amplitude signals, amplifying low amplitude signals or by doing a combination of both.
  • the compressing step in this method of one embodiment of the present invention may compress the dynamic range of the audio signal to less than about 10 db.
  • the final step of this method is a mirror equalizing step that produces a substantially opposite effect as the primary equalizing step. This mirror equalizing step has substantially the same crossover range as the primary equalizing step.
  • the primary equalizing step boosts the high frequency portions of an audio signal and attenuates the low frequency portions of an audio signal.
  • the mirror equalizing steps does the opposite; it attenuates the high frequency portions of an audio signal and boosts the low frequency portions of an audio signal.
  • each equalizing step at some frequency between the high frequency boosting and low frequency attenuating the effects of the boosting and attenuating intersect at the crossover point and produce a net gain of zero.
  • the primary equalizing step attenuates the high frequency portions of an audio signal and boosts the low frequency portions of an audio signal.
  • the mirror equalizing step does the opposite; it boosts the high frequency portions of an audio signal and attenuates the low frequency portions of an audio signal.
  • This embodiment also has a crossover point and a crossover range that may be chosen according to the specific application.
  • Another embodiment of the present invention includes a final equalizing step which, after the mirror equalizing step, adjusts the amplitude of the audio signal at frequencies predetermined to be related to sound presentation anomalies associated with the anticipated listening environment. These frequencies have been previously detected to be associated with acoustical anomalies. The frequency and magnitude of the adjustment may be preset in this step to reduce any anomalous responses. Thus, audio signals played through this final equalizing step, in environments in which the final equalizing step was prepared, may present music without anomalies.
  • the methods of the present invention may be performed by any number of processors. It may be performed by a computer, computer software, electrical circuit, an electrical chip programmed to perform these steps, or any other means to perform the method described.
  • the primary equalizing and mirror equalizing steps may use at least one filter.
  • the filters that operate in the high frequency portion of the signal in the primary and mirror equalizing steps produce an equal and opposite effect. That is, for example, if the high frequency filter in the primary equalizing step boosts the signal 8 db at 8 kHz then the high frequency filter in the mirror equalizing step attenuates the signal 8 db at 8 kHz. For example, if the high frequency filter in the primary equalizing step attenuates the signal 8 db at 8 kHz then the high frequency filter in the mirror equalizing step boosts the signal 8 db at 8 kHz.
  • the low frequency filter in the primary equalizing step boosts the signal 10 db at 100 Hz then the low frequency filter in the mirror equalizing step attenuates the signal 10 db at 100 Hz.
  • the low frequency filter in the mirror equalizing step boosts the signal 10 db at 100 Hz. In between these frequencies, the filters boost and attenuate at substantially linear functions of frequency.
  • Another embodiment of the present invention provides for a circuit for processing an audio signal comprising a primary equalizer, compressor, and mirror equalizer.
  • the primary equalizer produces an equalized audio signal by adjusting the amplitude of the low frequency portions of an audio signal corresponding to audible bass sounds and adjusting in the opposite direction the amplitude of the high frequency portions of an audio signal corresponding to audible treble sounds. These adjustments occur in a substantially linear function of frequency.
  • the above mentioned adjusting of the low frequency portions of an audio signal and the adjusting in the opposite direction of the high frequency portion of an audio signal intersect between a frequency range that produces a substantially negligible gain within this range.
  • the circuit may further comprise a compressor that produces a compressed audio signal by compressing the dynamic range of the audio signal by attenuating high amplitude signals, amplifying low amplitude signals or by doing a combination of both.
  • the compressor in this circuit may, for example, compress the dynamic range of the audio signal to less than about 10 db.
  • the circuit of this embodiment includes a mirror equalizer that produces a substantially opposite effect as the primary equalizer and has substantially the same crossover range as the primary equalizer.
  • the primary and mirror equalizers, in this circuit have a matched crossover point and a matched crossover range. At this crossover point the effect of these two adjustments on the audio signal exactly cancel each other out and produce a net gain of zero. Centered around this crossover point is the crossover range.
  • This crossover range in one embodiment of the present invention, is between approximately 600 Hz and approximately 1 ,000 Hz. In this embodiment, the crossover range is specially designed to be within the efficiency range of standard sound transducers and the human ear. Other embodiments may shift this crossover point as necessitated by the specific application.
  • the primary equalizer boosts the high frequency portions of an audio signal and attenuates the low frequency portions of an audio signal.
  • the mirror equalizer does the opposite; it attenuates the high frequency portions of an audio signal and boosts the low frequency portions of an audio signal.
  • the primary equalizer attenuates the high frequency portions of an audio signal and boosts the low frequency portions of an audio signal.
  • the mirror equalizer does the opposite; it boosts the high frequency portions of an audio signal and attenuates the low frequency portions of an audio signal.
  • at some frequency between the high frequency boosting or attenuating and low frequency attenuating or boosting the two processes intersect at the crossover point.
  • the circuit of the present invention may include a final equalizer which, after mirror equalization, adjusts the amplitude of the audio signal at frequencies predetermined to be related to sound presentation anomalies associated with the anticipated listening environment. These frequencies have been previously detected to be associated with acoustical anomalies and hard programmed into this circuit. The frequency and amount of adjustment performed may be preset in this final equalizer to reduce any anomalous responses. Thus, audio signals played through this final equalizer may present music absent anomalies associated with the listening environment in environments in which the final equalizer was prepared.
  • the circuit of this embodiment of the present invention may be implemented in a digital circuit, an analog circuit, or any combination of both. Any part of this circuit, equalizers or compressors, may individually be digital or analog, and may be coupled together. Those working in the art know various compressor and equalizer circuitry that may be implemented to produce the claimed results.
  • the primary equalizer and mirror equalizer may use at least one filter.
  • the filter that operates on the high frequency portion of the signal in the primary and mirror equalizers produce an equal and opposite effect. That is, for example, if the high frequency filter in the primary equalizer boosts the signal 8 db at 8 kHz then the high frequency filter in the mirror equalizer attenuates the signal 8 db at 8 kHz. For example, if the high frequency filter in the primary equalizer attenuates the signal 8 db at 8 kHz then the high frequency filter in the mirror equalizer boosts the signal 8 db at 8 kHz.
  • the low frequency filter in the primary equalizer boosts the signal 10 db at 100 Hz then the low frequency filter in the mirror equalizer attenuates the signal 10 db at 100 Hz.
  • the low frequency filter in the mirror equalizer boosts the signal 10 db at 100 Hz. In between these frequencies the filters boost and attenuate at substantially linear functions of frequency.
  • this circuit may present an audio signal after primary equalization, compression, and mirror equalization to an amplifier.
  • the circuit may also present an audio signal to a multi-phase equalizer for fine-tuning.
  • the system may also present an audio signal to a speaker.
  • a further embodiment of the present invention is the method of hard-programming adjustments into a multi-band equalizer that compensates for anomalies associated with the anticipated listening environment.
  • This method includes a number of steps.
  • the first step is presenting a test audio signal into an anticipated listening environment.
  • This test audio signal may be broadband noise, frequency sweeps, or any other test signal known in the art.
  • the test audio signal may be music that is well known and exhibits an understood response.
  • the next step in the method is detecting audio presentation anomalies associated with the anticipated listening environment from responses from the test audio signal. This step may be performed with a fast Fourier analyzer, a computer frequency analyzer, or any other system that analyzes the amplitude response of an audio signal over a broad range of frequencies.
  • a multi-band equalizer may be adjusted to compensate for these anomalies.
  • the magnitude of these adjustments at these set frequencies may be hard-programmed into a multi-band equalizer or a set of multi- band equalizers. Hard-programming sets the values so they are unchangeable by a future user. These values may be stored in some storage device or physically set. Thus, by using this multi-band equalizer in a system used in the anticipated listening environment or a reasonably similar environment, one may present music free from environmental anomalies.
  • one specific embodiment of the present invention comprises developing a multi-band equalizer that is hard-programmed with adjustments that compensate for anomalies associated with one model of automobile.
  • Each car of the same model likely presents very similar listening anomalies due to their similar size, shape, structural make-up, speaker placement, speaker quality, and speaker size.
  • a user may implement the method of this embodiment by playing a test signal through the cars sound system. While this test signal is playing a computer with frequency response software and hardware, such as a fast Fourier analyzing software, may detect anomalous responses by the environment to the test signal.
  • the system may detect standing waves that occur do to the small size of the car, it may detect frequencies that are accented or absorbed by the material in the car, or it may detect diffraction affects from the shape of the car. Once these anomalies are detected, the frequency and magnitude of the anomalies are noted and adjustments of the proper magnitude are made in a multi-band equalizer at those frequencies. This method may be repeated until environment related anomalies are reasonably adjusted for. The magnitude of the adjustments at each frequency is noted along with the frequency. These values are then hard programmed into equalizers and implemented in an audio system of cars of the same model. By following this method each car may ultimately have an audio system that presents anomalous free sound.

Landscapes

  • Tone Control, Compression And Expansion, Limiting Amplitude (AREA)
  • Circuit For Audible Band Transducer (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

La présente invention concerne de nouveaux systèmes, procédés et circuits qui sont utilisés pour effectuer une présentation sonore de qualité dans des environnements à bruit élevé. De manière spécifique, cette invention concerne des systèmes, procédés et circuits conçus pour traiter des signaux audio. Elle concerne également des procédés de réglage de programmation matérielle dans un égaliseur multibande qui compense des anomalies associées à un environnement d'écoute anticipée.
EP05776404A 2004-08-10 2005-08-01 Systeme et procede de traitement des signaux audio pour presentation dans un environnement a bruit eleve Withdrawn EP1779509A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US10/914,234 US7254243B2 (en) 2004-08-10 2004-08-10 Processing of an audio signal for presentation in a high noise environment
US10/922,107 US7274795B2 (en) 2004-08-10 2004-08-20 System for and method of audio signal processing for presentation in a high-noise environment
PCT/US2005/026925 WO2006020427A2 (fr) 2004-08-10 2005-08-01 Systeme et procede de traitement des signaux audio pour presentation dans un environnement a bruit eleve

Publications (2)

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EP1779509A2 true EP1779509A2 (fr) 2007-05-02
EP1779509A4 EP1779509A4 (fr) 2008-09-24

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EP05776404A Withdrawn EP1779509A4 (fr) 2004-08-10 2005-08-01 Systeme et procede de traitement des signaux audio pour presentation dans un environnement a bruit eleve

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EP (1) EP1779509A4 (fr)
KR (1) KR20070050930A (fr)
AU (1) AU2005274099B2 (fr)
BR (1) BRPI0515004A (fr)
CA (1) CA2576829C (fr)
NO (1) NO340702B1 (fr)
WO (1) WO2006020427A2 (fr)

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Also Published As

Publication number Publication date
CA2576829A1 (fr) 2006-02-23
WO2006020427A3 (fr) 2006-05-04
CA2576829C (fr) 2014-10-07
BRPI0515004A (pt) 2008-07-01
AU2005274099B2 (en) 2010-07-01
NO340702B1 (no) 2017-06-06
NO20071269L (no) 2007-04-30
KR20070050930A (ko) 2007-05-16
AU2005274099A1 (en) 2006-02-23
EP1779509A4 (fr) 2008-09-24
WO2006020427A2 (fr) 2006-02-23

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