Abstract: An audio signal processor is disclosed which has at least one audio signal input and at least one audio signal output as well as at least one control input, and an audio signal processing unit connected between audio signal input and audio signal output, the audio signal processing unit having a programmable indicator tone generator circuit to be driven via the control input and whose indicator tone signal is switched to the audio signal output in accordance with the state of the control input.

Abstract: An equalizer includes first and second differential amplifiers which have a common output and respective separate current sources, a first negative feed back circuit which feeds back a voltage signal extracted from the common output to the first differential amplifier, a second negative feed back circuit which feeds back the voltage signal to the second differential amplifier, and a filter circuit which is provided at either the first or the second negative feed back circuit and which differentiates frequency characteristics during signal amplification in the first and second differential amplifiers. Frequency characterstic is selected through selection of one of the current values of the respective current sources in response to a sound quality adjusting signal.

Abstract: An equalizer comprising a pair of high pass filters for receiving an input signal, each filter having gain, a first of the filters having gain which is substantially flat within its passband, a second of the filters having gain over a range of its passband which is controlled by an error signal, a differential amplifier for generating the error signal, having an output applied to a control input of the second filter, a pair of broadband amplitude peak detectors each for receiving an output signal of a respective one of the filters, apparatus for applying loop signals derived from outputs of the filters and passing though the peak detectors to corresponding inputs of the differential amplifier, apparatus for providing an offset to a loop signal derived from the output of the first filter, and apparatus for providing an output signal from the output of the second filter.

Abstract: An audio signal waveform emphasis processing device performs even-order integration on an input audio signal using one or a plurality of double integrators and even-order differentiation on the input audio signal using one or a plurality of double differentiators so as to obtain even-order integrated signal and even-order differentiated signal, and adds the even-order integrated signal and the even-order differentiated signal to the input audio signal in the same phase or reverse-phase with the input audio signal, whereby sound quality of audio signal in audio equipment is greatly improved by obtaining a desired frequency-gain characteristic without destroying the mutual phase relationship between, in particular, the middle frequency range vs. high frequency range and the middle frequency range vs. low frequency range frequency components close to the middle frequency range of an input audio signal.

Abstract: A digital circuit arrangement for influencing the frequency response of a digital audio signal as a function of frequency and/or amplitude, in which the input signal of the digital circuit arrangement is applied to a signal filter (3) having variable filter coefficients, the output signal of the signal filter (3), after addition to the input signal of the digital circuit arrangement, represents the frequency response-influenced output signal of the digital circuit arrangement, and the coefficients for the signal filter (3) are selected in dependence on the output signal of a control circuit to which the output signal of the signal filter (3) is applied, and which includes a control filter (7), a rectifier (8), a pulse shaper stage (9), a logarithmic circuit (12) and a circuit for determining the coefficients.

Abstract: A communication device (100) includes an equalizer (126) for correcting imbalance between in-phase and quadrature components of a received signal. The equalizer (126) determines peak amplitude for the in-phase and quadrature components, and the phase imbalance between both components (440). At least one of the in-phase and quadrature components is adjusted based on a function of the phase imbalance, and of the ratio of peak amplitudes of the in-phase and quadrature components (450, 460).

Abstract: An equalizer includes first and second differential amplifiers which have a common output and respective separate current sources, a first negative feed back circuit which feeds back a voltage signal extracted from the common output to the first differential amplifier, a second negative feed back circuit which feeds back the voltage signal to the second differential amplifier, and a filter circuit which is provided at either the first or the second negative feed back circuit and which differentiates frequency characteristics during signal amplification in the first and second differential amplifiers. A frequency characteristic is selected through selection of one of the current values of the respective current sources in response to a sound quality adjusting signal.

Abstract: The present invention provides an efficient audio equalization system in terms of the number of coefficients and taps of a digital filter. The processing efficiency of the system allows it to provide audio equalization with high resolution at low frequencies using a 1/20-th the number of coefficients and taps in equivalent prior art systems. The resulting reduction in cost makes it economical to incorporate the system in hi-fi systems, home theaters, automobiles, televisions, etc. providing significantly improved sound quality with little or no overall increase in cost of production.

Abstract: In an equalizer with n number of frequency ranges for digitized signals in which by means of n-1 cascaded filter circuits containing parallel connected digital low-pass filters and digital high pass filters whose respective frequency responses are linked by complementary transfer functions. A desired amplitude response is implemented via an increase or decrease in the amplitudes of adjacent frequency ranges in the associated filter circuit by weighting the outputs of the digital high-pass and low-pass filters, and a control unit forms the respective weighting factor from an equalizer control signal which contains the desired amplitude response as information.

Abstract: An equalizing circuit, for compensating frequency response perturbations in a loudspeaker caused by a recessed mounting of the loudspeaker, includes an input for receiving an audio signal, a peaking network coupled to the input for augmenting the audio signal in a first frequency range, a dipping network also coupled to the input for attenuating the audio signal in a second frequency range, and a combiner for combining an output of the peaking network to an output of the dipping network, an output of the combiner carrying a compensated audio signal for application to the loudspeaker.

Abstract: An audio signal amplifier device is disclosed, and includes two parallel compass controller circuits (6, 7), each of the circuits (6, 7) having the identical configuration and including a low compass controlling circuit (1, 8) having a plurality of transformers T.sub.1, T.sub.2 connected in series, a medium compass controlling circuit (2, 9) having a capacitor C.sub.2 and a resistor R.sub.3 connected in series, and a high compass controlling circuit (3, 10) having a capacitor C.sub.3 and an amplifier A.sub.2 connected in series, those three compass controlling circuits being coupled in parallel.The parallel compass controller circuits (6, 7) are connected in series through a pre-amplifier PA.sub.1, wherein the post-stage circuit (7) is coupled with an output transformer T.sub.4 through a pre-amplifier PA.sub.3, and the pre-stage circuit (6) is coupled with an input transformer T.sub.3 through a pre-amplifier PA.sub.2.

Abstract: An equalizer includes: a first attenuating circuit which receives an input signal and a first control signal and attenuates the input signal depending on the level of the first control signal; a filter having a predetermined frequency band which receives the output from the first attenuating circuit; an adding circuit which receives the output from the filter and the input signal so as to add the both and outputs the adjusted audio signal; a second attenuating circuit which receives the adjusted audio signal from the adding circuit and a second control signal, attenuates the adjusted audio signal depending on the level of the second control signal and sends out a phase inverted signal of the attenuated signal to the filter; wherein when a sound quality adjusting signal representing a sound quality emphasis is received, the first control signal having a level corresponding to the emphasis condition is generated and when a sound quality adjusting signal representing a sound quality attenuation is received, the

Abstract: A clipping circuit is coupled across the bass feedback shunt capacitor in an amplifier circuit to effectively reduce only high level bass signals while allowing level high frequencies to pass and allowing full boost to low level, low frequency signals.

Abstract: An audio frequency filter for a mixing console equalizer typically has a manual frequency control for setting its operating frequency range, and a manual gain control for controlling the gain of the filter independently of the set frequency range. The present filter further provides gain adjustment means for automatically adjusting the gain of the filter in dependence on the position of said operating frequency range relative to a reference frequency that lies intermediate the lower and upper ends of the audio frequency spectrum, the gain adjustment means being such that the filter gain is greater the further said operating frequency range is moved away from said reference frequency towards a said end of the audio spectrum. As a result, signal frequencies at the extreme of the audio spectrum are automatically boosted.

Abstract: A sound recording apparatus for equalizing a sound signal before the sound signal is recorded onto a recording medium includes an amplifier to which the sound signal is inputted and a simulated inductor circuit connected to the amplifier. The simulated inductor circuit includes a buffer whose input side is coupled to a predetermined bias, a plurality of capacitors for connecting the output side of the buffer to the amplifier, and a switch for changing an equalizing characteristic by changing over a capacitor among the plurality of capacitors.

Abstract: A bass compensation circuit for use in a sound reproduction device is provided with a second-order positive feedback type high-pass filter. The filter has an operational amplifier and a first positive feedback resistor, a first variable resistor connected to an input terminal for receiving an input signal, coupled with a second variable resistor for volume control, and a second resistor for determining a Q-value and a cut-off frequency of a second-order positive feedback type high-pass filter. The first variable resistor and the second resistor are inserted in series between the first resistor and the ground. Thus, the bass compensation circuit can amplify only low frequency signals which do not serve as a masking sound used in masking middle and high frequency signals and has a low level when the sound volume is low. Moreover, the Q-value and the cut-off frequency of the second-order positive feedback type high-pass filter can continuously be changed by using the second variable resistor.

Abstract: An adjustable equalizer network has a series chain of N all pass amplifier stages driving N+1 scaling circuits connected to a final summing circuit that adjusts the frequency response at M+1 frequency control points to obtain a predetermined ripple free minimum phase shift frequency response over a given frequency range. The scaling circuits have scaling coefficients, of magnitude and sign determined by Fourier analysis and an appropriate truncation function, such that the filter has a pass band representative of M+1 contiguous bands conjointly encompassing the frequency range. Calculation of the scaling coefficients and control of the scaling circuits is accomplished through digital computation and manipulation. Some embodiments may use passive circuits or linear analogue circuits as scaling circuits, controlled manually or by a computing device.

Abstract: Audio equalizer circuit for adjusting the amount of boost and cut. The circuit uses a combination negative feedback, positive feedback, negative feed-forward and positive feed-forward resulting in boost and cut characteristics which are entirely reciprocal and which, nonetheless provides an infinite-depth notch. The equalizer is fabricated with an ordinary band pass filter, resistors, potentiometer and operational amplifiers.

Abstract: Disclosed herein is a digital audio signal processing apparatus of a type wherein a graphic equalizer including a plurality of filters connected in series to one another is subjected to arithmetic operation processing to be defined to thereby output the result of its processing as data therefrom. When a change-over command is generated, one filter out of the plurality of filters except for filters positioned at both ends is supplied to one of two output terminals with output data of a filter immediately before said one filter, the stored data is applied to the input of a filter immediately after said one filter and output data of a final filter is applied to the other of said two output terminals so as to define two graphic equalizers.

Abstract: An operational amplifier (1) and resistors (11) and (12) damp an input signal (V.sub.1) by -6dB. Since a positive input terminal of the operational amplifier (1) is fixed at -3V, DC component of the input signal (V.sub.1) is down-shifted to -3V so that a signal (V.sub.2) is obtained. The signal (V.sub.2) is inputted to an electronic volume (100) wherein the signal (V.sub.2) is damped thereby a signal (V.sub.3) is obtained. An operational amplifier (2) and resistors (13) and (14) amplify the signal (V.sub.3) by 6dB. Since a positive input terminal of the operational amplifier (2) is fixed at OV, DC component of the signal (V.sub.3) is up-shifted to OV thereby a signal (V.sub.5) is obtained. The signal which is to be processed in the electronic volume has only a half voltage relative to that of the input signal.

Abstract: An adaptive high pass filter comprises a switched capacitor filter (11) operable as a high pass filter, detecting circuits (14, 15, 16) for detecting low frequency signal components included in an input signal (V.sub.i) and control circuits (17, 18, 19) for controlling the switched capacitor filter (11) responsive to the detecting circuits. In this adaptive high pass filter, a cut-off frequency thereof is controlled responsive to low frequency signal components of the input signal. Therefore, a reproduced voice is not varied dependent upon changes in a quality of voice and surrounding environments. Thus, the reproduced voice is much closer to its original voice.

Abstract: An audio processor consisting of a "single-ended" dynamic noise reduction system cascaded and cross-coupled with a program-adaptive dynamic equalizer. The audio at the output has a consistent subjective spectral texture even if the spectral texture of the input audio varies widely. Further, although the system often adds high frquency energy to the audio, it does not increase the perceived noise level and is free from audible noise modulation.

Abstract: A tone control shelving equalizer providing low shelf (bass) boost and cut, and high shelf (treble) boost and cut is disclosed wherein the active filter stages provide sharpened (accelerated) amplitude versus frequency response characteristics at the band transitions to leave the center frequencies uncorrupted by out-of-band effects of the tone controls while maintaining circuit stability and avoiding dropouts due to excessive filter phase shifts. Each high and low end band filter network has multiple poles and offset zeros located at a frequency offset so as to restrict the maximum phase shift of the filter to within a safe level not greater than about 90.degree..

Abstract: An improved tone control device for controlling a tone within an audio frequency range in a combined mode of fine compensation for frequency characteristic as in the graphic equalizer and coarse tone control as in the bass/treble tone control circuit by making use of corresponding circuits in common for the both control without increasing the scale of circuitry, whereby the audio frequency is divided into N and M (<N) bands and the first manipulation input is fed to each one of the N bands while the second manipulation input is fed to each one of the M bands, the second input is converted into weights for each band in the N bands as by increasing or decreasing the gain thereof with a conversion means and setting the gain of each band by utilizing a gain setting means in accordance with the amount of first manipulation input as well as the weighted gain for an intended tone control.

Abstract: A sound reproduction system suitable for automobile, the reproduction system having a band-pass filter, a phase-shifter for shifting the output of the band-pass filter and a mixer which mixes the output of the phase-shifter with the original audio signal at a suitable mixing ratio, whereby a low frequency standing wave which is generally produced in the small automobile room may be eliminated, thereby providing a desirable frequency response characteristic.

Abstract: Apparatus for equalizing a soundfield comprises an amplifier and a gain control circuit for selectively adjusting the gain of the amplifier as a function of frequency in response to data values received by the gain control circuit. The apparatus has power supply terminals for supplying operating current from an external power source to the amplifier and the gain control circuit. In addition, the apparatus comprises an electronic storage device for storing data values and applying those data values to the gain control circuit. The stored data values are maintained in the apparatus upon interruption of the supply of operating current to the power supply terminals. The apparatus has an input port for applying data values to the storage device, and does not have manually actuable controls for selectively adjusting the stored data values.

Abstract: A multi-band graphic equalizer is provided that includes a plurality of controllable frequency response determining elements, each element having a primary effect in its primary frequency band and a secondary effect in at least one adjacent frequency band, a graphic input device for entering an input that graphically represents a desired frequency response characteristic, and a controller connected between the input means and the frequency response determining elements for calculating the necessary frequency response characteristic for each controllable frequency response element based on the in band and out of band effects of each element to produce the desired overall frequency response characteristic and for generating a plurality of sets of control signals, one set of control signals for each frequency response determining element, so that the overall frequency response characteristic produced by the plurality of frequency response determining elements is as close as possible to the desired frequency resp

Abstract: An equalizer circuit is disclosed having adjustable bandpass filters connected with operational amplifiers in feedforward and feedback paths so as to form frequency selective boost and cut signal components, which are then combined to form the equalized output signal by a subtractive operation with a direct unfiltered signal path arranged in parallel with the filtered feedforward and feedback paths. The circuit exhibits a constant-Q operation in that it can be adjusted for selected frequency boost and cut without distortion of the component bandwidths of the individual filters.

Abstract: A digital equalizer for audio system applications is based on a FIR (finite impulse response) digital filter whose amplitude and phase/frequency characteristics can be respectively independently established in accordance with input data representing an arbitrary amplitude/frequency characteristic and input phase data from which an arbitrary phase/frequency characteristic for the filter can be derived. In addition to audio frequency response equalization, the apparatus can be provided with a microphone howl suppression function.

Abstract: A manually operated or automatic equalizer (1) with adjustable band filters for varying the frequency characteristic of an electric signal presented to an input (2) and for applying a frequency characteristic-adapted electric signal to an output (3). The equalizer has a plurality of band filters (F.sub.1 to Fn) with their bands located adjacent to one another in a given frequency range. The distance (frequency separation) between the central frequencies of filters having neighboring bands is greater than the distance between the central frequencies of one third octave filters having neighboring bands located at at least approximately the same frequencies as those of the band filters (F.sub.i). At least those band filters (F.sub.1 to F.sub.m) whose bands are located in the low-frequency part (f<450 Hz) of the frequency range have a central frequency (fc.sub.i) which is variable. A digital filter which can be used as a band filter in the equalizer is also described.

Abstract: A method of improving the frequency reproduction at frequencies higher than a certain break frequency (fs) of a bass amplifier known per se within the audio frequency range. The amplifier has a low-pass filter portion (ACE1) and a power amplifier portion (EF) with a current feedback portion (ACE2) in order to get a negative output impedance against the loudspeaker. According to the invention high-pass filtration is carried out from the break frequency (fs) and upwards to about 20 kHz of the signal coming to the amplifier and thereafter a phase shift (.rho.) is carried out so that a cophasal state is obtained at the break frequency (fs) before the power amplifier portion (EF).

Abstract: A sound system comprises four channels, each having a low level input for coupling to a source of program material, multiple, independently selectable gyrators providing equalization poles, and an input stage for independently and selectively coupling one or more of the gyrators to the low level input. Each channel further includes an amplifier, a buffer for coupling the selected one or more of the multiple gyrators to the amplifier, and a transducer coupled to the amplifier. A filter is coupled between the buffer and the amplifier. The filter has a variable lower corner frequency and a control input terminal. The sound system further comprises a low-pass filter circuit coupled between the amplifier and the control input terminal of the variable corner frequency filter for generating a feedback signal.

Abstract: An automatic dynamic equalizer includes left and right input terminals, an input adder and left and right output adders. The left and right input terminals are connected to inputs of the input adder and inputs of the left and right output adder, respectively. The output of the input adder is connected to the input of a 2:1 compressor. The output of the 2:1 compressor is connected to the input of a bandpass filter having a transmission in the low bass frequency region centered at a frequency of about 60 Hz. The output of the bandpass filter is coupled to inputs of the left and right output adders.

Abstract: An audio crossover filter which automatically tunes the crossover frequency according to the content of the program audio which is being filtered.

Abstract: An NF (Negative Feedback) tone control circuit in which a circuit gain of unity is maintained for a flat frequency response without the addition of active components. A voltage divider circuit which divides only an a.c. component of the output of an operational circuit is connected between the output of the operational amplifier circuit and a variable impedance circuit, the latter including the variable resistors of the tone control circuit.

Abstract: An adjustable equalizer network comprises a series chain of N all pass amplifier stages driving M minimum phase shift transversal filters connected to a final summing circuit that includes means to adjust each filter output to obtain a ripple free predetermined frequency response over a given frequency range. Each filter includes N+1 scaling circuits connected to an intermediate summing circuit; the scaling circuits have scaling coefficients, of magnitude and sign determined by Fourier analysis and an appropriate truncation function, such that the filter has a pass band representative of one of M contiguous bands conjointly encompassing the frequency range.

Abstract: A tone control has a transfer function characterized by a zero and pole on the real axis spaced from the imaginary axis by an audible frequency with adjustment of a potentiometer causing one of the zero and pole to slide along the real axis while the other remains stationary. A treble control with fixed pole at 1 kHz from the imaginary axis has a potentiometer connected to an input terminal with its arm connected to an output terminal and is in series with a resistor and capacitor between the input terminal and ground. A bass cut control has a capacitor connected to an input terminal in series with a resistor between the input terminal and ground. The capacitor is shunted by a potentiometer having its arm connected to an output terminal. A treble tone control circuit with both cut and boost has a center tapped potentiometer with first and second opposed ends connected to + inputs of first and second operational amplifiers, each having a feedback connection with the - input.

Abstract: A tone control circuit including an amplifier having a continuously adjustable frequency response control for varying the effect of low and high frequency filters upon the amplifier, and incorporating a novel distortion and transient suppression circuit is disclosed. A programmable variable resistance is coupled between an input and an output of said amplifier to attenuate circuit low frequency response while initially varying resistor value in response to a programming distortion/transient control signal. Thereafter, overall amplifier gain is further varied in response to the programming distortion/transient control signal by further adjusting the variable resistor value. Various embodiments of the invention provide both continuous and discrete control of tone and volume responsive to both excessive low frequency signal and transients. The present invention is implemented in both discrete and monolithic embodiments, which include both linear and CMOS technologies.

Abstract: A circuit for selectively combining an input signal with a selected fraction of the input signal, twice differentiated, is comprised of two amplifier circuits, each having two input stages and a dual output stage with one output stage of each amplifier circuit being gain controllable in response to a control signal. One of the gain controllable output stages of one amplifier and the non-gain controlled output stage of the other amplifier are connected to a single combined output terminal. The other output stages are connected to a circuit ground. An input signal is supplied to one input stage of each amplifier circuit and the same input signal, after being double differentiated by means of an inductor and capacitor, is supplied in noninverted form to the other input stage of one of the amplifier circuits and is supplied in inverted form to the other input stage of the other amplifier circuit.

Abstract: The present invention relates to apparatus for electroacoustic energy conversion and particularly to a conversion apparatus comprising a channel for an electrical signal to be converted, said channel comprising in series connection signal processing circuitry for processing said electrical signal and having in sequence a power amplifier and an electroacoustic transducer, such as a loudspeaker. In accordance with the teachings of the present invention an electroacoustic energy converter apparatus is provided which introduces emphasis in a signal frequency range from 50 kHz up, preferably directly before delivering the signal to the power amplifier stage.

Abstract: A programmable adjustable distortion amplifier circuit has a first channel having an adjustable gain and a filter for filtering high and low frequency components of signal processed by the first channel, a second channel having an adjustable gain and a filter for filtering high and low frequency components of signal processed by the second channel, a parametric equalizer providing adjustable preselectable frequency bandwidth and a vacuum tube amplifier and support circuitry permitting adjustment of distortion of signal processed by the second channel by a preselected amount. An optional phase shift circuit delays a portion of signal processed by the second channel with the delayed portion provided to the second channel downstream of the parametric equalizer but upstream of the tube. A summing device combines output signals of the first and second channels for input to an adjustable gain control for subsequent input to audio speakers.

Abstract: An automatic dynamic equalization circuit has a potentiometer having a tap shunted by an active resonator circuit including a capacitor shunted by an active circuit presenting a high Q inductive reactance that is resonant at substantially 50 Hz and provides essentially no boost in the middle range of frequencies above 150 Hz with roll-off below about 45 Hz.

Abstract: Passive frequency compensation networks are disclosed which extend and smooth the base response of loudspeakers. The compensation networks include a series resonant circuit including a resistor, inductor and capacitor with the voice coil of the loudspeaker connected in parallel with the resistor and inductor. In another embodiment of the invention, a second inductor is loosely coupled to the first inductor to create a tuned transformer which eliminates ripples in the mid base response of the speaker.

Abstract: A method for processing the audio signal in a loudspeaker system prior to delivery to the loudspeaker and the apparatus for such processing is disclosed. Uniform acoustic output with respect to frequency at frequencies below the resonant frequency of the loudspeaker system is achieved by changing the strength of the signal at a constant rate in inverse proportion to audio signal frequencies from a frequency below the resonant frequency to a frequency at least one octave above the resonant frequency. A method and apparatus for limiting the audio signal to prevent distortion is also disclosed.

Abstract: A circuit providing a known change in a parameter of a function without interfering with the basic operation of the function is utilized in an audio circuit "loudness contour" control. Bass and treble controls function independently of the volume setting while desired contours are obtained at each volume control setting.

Abstract: A low-noise bass-control device, which is digitally controllable in a simple manner, comprises an amplifier having an output connected to the series arrangement of a capacitor and a tapped resistor chain. The taps on said resistor chain are connected to an inverting input of the amplifier via a first switch and to the output of the control device via a second switch.

Abstract: A tone control circuit is provided having several parallel channels each of which comprises an electronic potentiometer. In each of the channels is disposed a filtering element. Thus, for an output terminal common to the different channels, each of the channels comprises a filter comprising a series element corresponding to the series element of this channel and a parallel element corresponding to the series elements placed in parallel of the other channels. The present invention simplifies the construction of tone control circuits in the form of integrated circuits.

Abstract: In an active equalizer for selectively boosting or attenuating predetermined frequencies of audio or other electrical signals, and which comprises an inverting amplifier having an inverting input which receives the input signal through an input resistance and an output connected with the inverting input through a feedback resistance and at which the equalized output is derived, and an active filter for determining the frequencies to be boosted or attenuated; there is further provided a change-over switch having a boosting position in which the input signal is applied to the active filter, an attenuating position in which the output of the inverting filter is applied to the active filter and a neutral position, and a potentiometer connected between the output of the active filter and the inverting input of the inverting amplifier and being operable in concert with the change-over switch for determining the extent to which the frequencies determined by the active filter are boosted or attenuated.

Abstract: Electric circuitry to correct for spurious sound pressure responses of audio transducers is disclosed. In particular, electric circuitry to compensate for "pre-shoot" of an audio transducer system is disclosed. The circuitry includes a delay line electric circuit carrying the bulk of the electric signal energy to the audio transducers and a parallel circuit to feed forward in real time an electric signal replica of diminished amplitude to the audio transducers. The replica thereby cancels or greatly minimizes the "pre-shoot" or prior undesired significant sound pressure responses of the audio transducers. The circuits include, in combination with the feed forward circuit, additional circuitry to counteract subsequent undesired significant sound pressure amplitude responses such as resonance (ringing). The new circuits utilize series resonant circuits in parallel to ground with the audio transducers as the preferred means to counteract the subsequent undesired sound pressure responses.

Abstract: An audio system, characterized in that the audio signal passes through a preamplifier, equalization unit and electronic cross-over and before reaching the power amplifiers, which drive the speakers, is modified by an electronic resonance control correction (ERCC) circuit.