Sound reproducing system having sonic image localization networks

Claim 2

A sound reproducing system for localizing a sonic image at a desired point with respect to a listener, comprising: first means for dividing an input signal into three or more separated signals and varying the voltage level of each separated signal relative to the voltage level of another separated signal; first and second loudspeakers located in front of said listener and receptive of two of said voltage-varied, separated signals respectively; and second means receptive of the remainder of said voltage-varied signals for generating a sound at a specified point, said specified point and said loudspeakers being located symmetrically with respect to said listener, the location of said specified point being 90 degrees to the normal to said listener, whereby the operation ofsaid voltage varying means causes a sonic image to be localized at a point within an area between one of said loudspeakers and said specified point.

Claim 3

A sound reproducing system as claimed in claim 1, wherein said first means comprises means for dividing said input signal into four separated signals, and wherein said second means comprises third and fourth loudspeakers receptive of said voltage-varied signals.

Claim 4

A sound reproducing system as claimed in claim 2, wherein said first means comprises first 2-channel dividing means for dividing said input.signal into two.separated- signals, a pair of first and second voltage adjusting means for varying the voltage levels of said two separated signals respectively, second and third 2-channel dividing means for dividing the outputs of said first and second voltage adjusting means respectively, and a set of third, fourth, fifth and sixth voltage adjusting means for varying the voltage levels of the signals separated by said second and third 2-channel dividing means respectively.

Claim 5

A sound reproducing system as claimed in claim 2, wherein said first means comprises 3-channel dividing means for dividing said input signal into three.separated signals, a set of three switches respectively connected to receive the three separated signals, a set of three 2-channel dividing means for dividing each of the outputs of said switches into two separated signals, a set of six variable resistors for varying each of the signals divided by the.last-mentioned dividing means, and two combining means for respectively combining four of the outputs of said variable resistors in two pairs to derive a set of four output signals from said variable resistors.

Claim 6

A sound reproducing system as claimed in claim 1, wherein said first means comprises first 4-channel dividing means for dividing a first input signal into a first set of four separated signals, second 4-channel dividing means for dividing a second input signal into a second set of four separated signals, first voltage adjusting means for relatively varying the voltage levels of the four separated signals of the first set, second voltage adjusting means for relatively varying the voltage levels of the four separated signals of the second set, and a set of four combining means for arithmetically combining the outputs of said first and second voltage adjusting means to generate a set of four output signals, and wherein said second means comprises third and fourth loudspeakers_located at ±90 degrees to the normal to said listener, said first, second, third and fourth loudspeakers being receptive of said output signals of said combining means respectively.

Claim 7

A sound reproducing system as claimed in claim 2, further comprising fifth and sixth loudspeakers located at the rear of, and symmetrically with respect to, said listener.

Claim 8

A sound reproducing system as claimed in claim 6, wherein said first means comprises 6-channel dividing means for dividing said input signal into six separated signals, and means for relatively adjusting the voltage levels of said six separated signals for application to said first, second, third, fourth, fifth and sixth loudspeakers, respectively.

Claim 9

A sound reproducing system as claimed in claim 1, wherein said second means comprises localization network means for generating a localized signal for application to one of said first and second loudspeakers to localize a sonic image at a point 90 degrees to the normal to said listener.

Claim 10

A sound reproducing system as claimed in claim 8, wherein said first means comprises 4-channel dividing means for dividing said input signal into four separated signals and means for relatively adjusting the voltage levels of the four separated signals to generate two voltage-adjusted signals for application to said first and second loudspeakers and other two voltage-adjusted signals for application to said localization network means.

Claim 11

A sound reproducing system as claimed in claim 8, wherein said localization network means comprises first transfer circuit means connected to receive one of said voltage-varied signals to impart thereto a first transfer function represented by H φ1 /H 11 , where H φ1 represents the acoustic transfer function between said sonic image at 90 degrees to said normal and one of the listener's ears, and H 11 represents the acoustic transfer function between one of said first and second loudspeakers and one of the listener's ears, said localization network means further comprises a second transfer circuit means connected to receive the output signal of said first transfer circuit means to impart thereto a second transfer function represented by the relation (H 11 H φ2 - H 12 H φ1 )/(H 11 H φ1 - H 12 H φ 2), where H 02 represents the acoustic transfer function between said sonic image and the other of the listener's ears, and H 12 represents the acoustic transfer function between the other of said first and second loudspeakers and the other of said listener's ears.

Claim 12

A sound reproducing system as claimed in claim 8, wherein said first means comprises 4-channel dividing means for dividing said input signal into four separated signals and voltage level adjusting means for relatively adjusting the voltage levels of said four separated signals for application to said first and second loudspeakers and to said localization network means.

Claim 13

A sound reproducing system as claimed in claim 8, wherein said first means comprises first 4-channel dividing means for dividing a first input signal into a first set of four separated signals, second 4-channel dividing means for dividing a second input signal into a second set of four separated signals, first voltage level adjusting means for relatively adjusting the voltage levels of said four separated signal of the first set, second voltage level adjusting means for relatively adjusting the voltage levels of the four separated signals of the second set, and a set of four combining means for arithmetically combining the outputs of said first and second voltage level adjusting means to generate four output signals for application to said first and second loudspeakers and to said localization network means.

Claim 14

A sound reproducing system as claimed in claim 8, wherein said localization network means comprises first and second localization networks each having said first and second acoustic transfer functions to generate first and second localized signals for application to said first and second loudspeakers respectively to localize sonic images on opposite sides of said listener at 90 degrees to the normal to the listener.

Claim 15

A sound reproducing system as claimed in claim 2,3,4, 5,6 or 7, wherein the signals applied to said third and fourth loudspeakers are of equal amplitude and in phase with each other to localize a sonic image within the area described by .all of said loudspeakers.

Claim 16

A sound reproducing system as claimed in claim 8,9,10, 11,12 or 13, wherein the signals applied to said localization network means are of equal amplitude and in phase with each other to localize a sonic image within the area described by all of said loudspeakers and said localized sonic images.

Claim 17

A sound reproducing system as claimed in claim 8, 9, 10, 11, 12 or 13, further comprising means for generating a plurality of primary echo signals at respectively delayed intervals in response to said input signal for application to said localization network means.

Claim 18

A sound reproducing system as claimed in claim 16, wherein said echo signal generating means includes a plurality of level adjusting means for relatively adjusting the signal levels of said primary echo signals to each other.

Claim 19

A sound reproducing system as claimed in claim 16, further comprising means for generating a reverberation signal at a delayed time in response to said input signal, said delayed time being greater than the maximum delay interval of said primary echo signals, said reverberation signal being applied to said localization network means.

Claim 20

A sound reproducing system as claimed in claim 16, further comprising means for arithmetically combining output signals from said localization network means with the signals applied to said first and second loudspeakers.

Claim 21

A sound reproducing system as claimed in claim 18, further comprising means for applying said reverberation signal to said first and second localization networks and means for introducing a delay time to the reverberation signal applied to said second localization network relative to the signal applied to said first localization network.

Claim 22

A sound reproducing system as claimed in claim 14, further comprising at least one attenuator provided in the circuit between said voltage varying means and one of said loudspeakers.

Claim 23

A sound reproducing system as claimed in claim 13, wherein said first-means comprises first 2-channel dividing means for dividing a first input signal into a first pair of separated signals, second 2-channel dividing means for dividing a second input singal into a second pair of separated signals, first voltage adjusting means for adjusting the voltage levels of said separated signals of the first pair relative to each other, second voltage adjusting means for adjusting the voltage levels of said separated signals of the second pair relative to each other, further comprising first combining means receptive of one of the outputs of said first voltage adjusting means, the other output of said first voltage adjusting means being applied to said first localization network to apply one of the localized output signals thereof to said first combining means, second combining means receptive of one of the outputs of said second voltage adjusting means, the other output of said second voltage adjusting means being applied to said second localization network to apply one of the localized output signals thereof to said second combining means, the other localized signals of said first and second localization networks being respectively applied to said second and first combining means, the output signals of said first and second combining means being respectively applied to said first and second loudspeakers.

Claim 24

A sound reproducing system as claimed in claim 1, further comprising a keyboard connected to receive a plurality of synthesized musical signals to select one of said musical signals and conversion circuit means for converting the selected musical signal to the note of a desired musical instrument for application to said.first means as said input signal.

Claim 25

In a sound reproducing system having first and second loudspeakers located in front of a listener, a signal processing circuit comprising means for dividing an input audio signal into a plurality of separated signals, means for relatively varying the voltage levels of the separated signals to each other, two of the output signals of said voltage varying means being adapted for application to said loudspeakers respectively, and localization network means receptive of the remainder of the output signals of said voltage varying means to generate localized signals for application to said loudspeakers to localize a sonic image ata point 90 degrees to the normal to said listener,-said sonic image and said loudspeakers being located symmetrically with respect to said listener.

Claim 26

In a sound reproducing system having first and second loudspeakers located in front of a listener, a signal processing circuit comprising means for dividing an input audio signal into a plurality of separated signals, means for relatively varying the voltage levels of the separated signals to each other, two of the output signals of said voltage varying means being adapted for application to said loudspeakers respectively, and localization network means receptive of the remainder of the output signals of said voltage varying means to generate localized signals for application to said loudspeakers to localize a sonic image ata point 90 degrees to the normal to said listener,-said sonic image and said loudspeakers being located symmetrically with respect to said listener.

Claim 27

In a sound reproducing system having first and second loudspeakers located in front of a listener, a signal processing circuit comprising first and second means for dividing first and second input audio signals respectively into a plurality of separated signals, first means for relatively. varying the voltage levels of the signals separated by said first dividing means, second means for relatively varying the voltage levels of the signals separated by said second dividing means, a first localization network associated with said first voltage varying means for generating first localized signals in response to one of the outputs of said first voltage varying means, a second localization network associated with said second voltage varying means for generating second localized signals in response to one of the outputs of said second,voltage varying means, and first and second combining means for arithmetically combining the first and second localized signals with the other outputs of said first and second voltage varying means for generating first and second output signals for application to said first and second loudspeakers, respectively, to localize a sonic image at a point 90 degrees to the normal to said listener, the locations of said loudspeakers and said sonic image being symmetrical with respect to said listener.

Claim 28

In a sound reproducing system having first and second loudspeakers located in front of a listener, a signal processing circuit comprising first and second means for dividing first and second input audio signals respectively into a plurality of separated signals, first means for relatively. varying the voltage levels of the signals separated by said first dividing means, second means for relatively varying the voltage levels of the signals separated by said second dividing means, a first localization network associated with said first voltage varying means for generating first localized signals in response to one of the outputs of said first voltage varying means, a second localization network associated with said second voltage varying means for generating second localized signals in response to one of the outputs of said second,voltage varying means, and first and second combining means for arithmetically combining the first and second localized signals with the other outputs of said first and second voltage varying means for generating first and second output signals for application to said first and second loudspeakers, respectively, to localize a sonic image at a point 90 degrees to the normal to said listener, the locations of said loudspeakers and said sonic image being symmetrical with respect to said listener.

Claim 29

A signal processing circuit as claimed in claim 25, wherein each of said localization networks comprises first transfer circuit means for imparting the input signal supplied from the associated voltage varying means a first transfer function described by H φ1 /H 11 and second transfer circuit means for imparting the output signal of said first transfer circuit means a second transfer function described by (H 11 H φ2 - H 12 H φ1 )/(H 11 H φ1 - H 12 H φ2 ), where H φ1 represents the acoustic transfer function between said sonic image at 90 degrees to said normal and one of the listener's ears, HØ2 represents the acoustic transfer function between said sonic image and the other of said listener's ears, H11 represents the acoustic transfer function between said first loudspeaker and one of the listener's ears and H 12 represents the acoustic transfer function between said second loudspeaker and the other of said listener's ears.