US 4,229,619 A · Method and apparatus for driving a multi way speaker system

Abstract

A multi way speaker system comprises an amplifier, frequency dividing network including a plurality of filters, a plurality of speakers respectively responsive to the output signals of the filters, and a summing circuit responsive to the output signals of the filters for producing a composite signal to be fed back to the input of the amplifier to establish a negative feedback loop. Because of the feedback loop undesirable influences by various elements included in the filters are diminished and thus the speakers reproduce audio frequencies with high fidelity. At least one equalizer may be employed in the feedback loop, while auxiliary filters may be used in such a manner that the output terminals of the auxiliary filters are connected to only the summing circuit so that the output signals of the auxiliary filters are added to an output signal of at least one filter of the frequency dividing network. In order to supply the network with the output signal of the amplifier and to feed the composite signal back to the amplifier a three-wire coaxial cable may be used. The three-wire coaxial cable is used in such a manner that the composite signal flows through a conductor which is shielded by another conductor carrying the output signal of the amplifier. A switch and a resistor network may be used in the feedback loop for avoiding undesirable oscillation and output level variation.

Claims23

Dependent claims

A method of driving a multi way speaker system comprising the steps of:

(a) amplifying an audio signal;
(b) dividing the amplified audio signal into a plurality of frequency ranges;
(c) driving a plurality of speakers the frequency characteristics of which respectively correspond to said frequency ranges, by the divided audio signals respectively;
(d) producing a composite signal by combining at least two of the divided audio driving signals with each other;
and
(e) feeding said composite signal back to a stage which carries out said step of amplifying said audio signal so as to establish a negative feedback loop.

3 more elements

An apparatus for driving a multi way speaker system comprising:

(a) an audio amplifier for amplifying an audio signal;
(b) a frequency dividing network responsive to the output signal of said amplifier for dividing the amplified signal into a plurality of frequency ranges;
(c) a plurality of speakers responsive to the output signals of said frequency dividing network;
(d) means for producing a composite signal by combining at least two of the speaker driving signals supplied by said frequency dividing network with each other;
and
(e) means for feeding said composite signal back to said amplifier so as to establish a negative feedback loop.

3 more elements

An apparatus for driving a multi way speaker system comprising:

(a) an audio amplifier for amplifying an audio signal;
(b) a frequency dividing network responsive to the output signal of said amplifier for dividing the amplified signal into high, middle and low-frequency ranges, said frequency dividing network including a high-pass filter, a bandpass filter and a low-pass filter for respectively transmitting a high-frequency range signal, a middle-frequency range signal and a low-frequency range signal, said high-pass filter having an attenuation slope of 12 dB/oct in a range below a crossover frequency between said high-frequency range and said middle frequency range, said bandpass filter having a first attenuation slope of -12 dB/oct in a range over said crossover frequency between said high and middle frequency ranges and a second attenuation slope of 12 dB/oct in a range below another crossover frequency between said middle-frequency range and said low-frequency range, said low-pass filter having an attenuation slope of -12 dB/oct in a range over said another crossover frequency between said middle and low frequency ranges;
(c) speakers including a tweeter responsive to the output signal of said high-pass filter, a squeaker responsive to the output signal of said bandpass filter and a woofer responsive to the output signal of said low-pass filter;
(d) first, second and third equalizers respectively responsive to the output signals of said high-pass, bandpass and low-pass filters, said equalizers have inverse characteristics in said frequency ranges to the attenuation slopes of said filters, said first equalizer having an equalization slope of -6 dB/oct in a range below said crossover frequency between said high and middle frequency ranges, said second equalizer having a first equalization slope of 6 dB/oct in a range over said crossover frequency between said high and middle frequency ranges and a second equalization slope of -6 dB/oct in a range below said another crossover frequency between said middle and low frequency ranges, said third equalizer having an equalization slope of 6 dB/oct in a range over said another crossover frequency;
(e) a summing circuit including first, second and third resistors respectively responsive to the output signals of said first, second and third equalizers, said first, second and third resistors being connected to each other at one end thereof so as to produce a composite signal at a junction connecting said resistors;
(f) a voltage divider responsive to said composite signal for feeding said composite signal back to an input of said amplifier so as to establish a negative feedback loop.

3 more elements

An apparatus for driving a multi way speaker system comprising:

(a) an audio amplifier for amplifying an audio signal;
(b) a frequency dividing network responsive to the output signal of said amplifier for dividing the amplified signal into high, middle and low frequency ranges, said frequency dividing network including first and second high-pass filters, a bandpass filter and first and second low-pass filters for respectively transmitting a high-frequency range signal, a middle-frequency range signal and a low-frequency range signal, said first and second high-pass filters respectively having attenuation slopes of 12 dB/oct and 6 dB/oct in a range below a crossover frequency between said high-frequency range and said middle frequency range, said bandpass filter having a first attenuation slope of -12 dB/oct in a range over said crossover frequency between said high and middle frequency ranges and a second attenuation slope of 12 dB/oct in a range below another crossover frequency between said middle-frequency range and said low-frequency range, said first and second low-pass filters respectively having attenuation slopes of -12 dB/oct and -6 dB/oct in a range over said another crossover frequency between said middle and low frequency ranges;
(c) speakers including a tweeter responsive to the output signal of said first high-pass filter, a squeaker responsive to the output signal of said bandpass filter and a woofer responsive to the output signal of said first low-pass filter;
(d) an equalizer responsive to the output signal of said bandpass filter, said equalizer having inverse characteristics in corresponding frequency ranges to the attenuation slopes of said bandpass filter, a first equalization slope of 6 dB/oct in a range over said crossover frequency between said high and middle frequency ranges and a second equalization slope of -6 dB/oct in a range below said another crossover frequency between said middle and low frequency ranges;
(e) a summing circuit including first, second and third resistors respectively responsive to the output signal of said equalizer, said second high-pass filter and said second low-pass filter, said first, second and third resistors being connected to each other at one end thereof so as to produce a composite signal at a junction connecting said resistors;
(f) a voltage divider responsive to said composite signal for feeding said composite signal back to an input of said amplifier so as to establish a negative feedback loop.

3 more elements

An apparatus for driving a multi way speaker system comprising:

(a) an audio amplifier for amplifying an audio signal;
(b) a frequency divider network responsive to the output signal of said amplifier for dividing the amplified signal into high, middle and low frequency ranges, said frequency dividing network including first and second high-pass filters, a bandpass filter and first and second low-pass filters for respectively transmitting a high-frequency range signal, a middle-frequency range signal and a low-frequency range signal, said first and second high pass filters respectively having attenuation slopes of 6 dB/oct in a range below a crossover frequency between said high-frequency range and said middle frequency range, said bandpass filter having a first attenuation slope of -6 dB/oct in a range over said crossover frequency between said high and middle frequency ranges and a second attenuation slope of 6 dB/oct in a range below another crossover frequency between said middle-frequency range and said low-frequency range, said first and second low-pass filters respectively having attenuation slopes of -6 dB/oct in a range over said another crossover frequency between said middle and low frequency ranges;
(c) speakers including a tweeter responsive to the output signal of said first high-pass filter, a squeaker responsive to the output signal of said bandpass filter and a woofer responsive to the output signal of said first low-pass filter;
(d) a summing circuit including first, second and third resistors respectively responsive to the output signals of said bandpass filter, said second high-pass filter and said second low-pass filter, said first, second and third resistors being connected to each other at one end thereof so as to produce a composite signal at a junction connecting said resistors;
(e) a voltage divider responsive to said composite signal for feeding said composite signal back to an input of said amplifier so as to establish a negative feedback loop.

2 more elements

Dependencies are inferred from the claim text.

Method and apparatus for driving a multi way speaker system

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Method and apparatus for driving a multi way speaker system

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Abstract

Claims23