Sound signal changing circuit

Claim 2

A circuit for eliminating a selected band of audio frequencies from an audio spectrum and inserting another audio signal into said selected band comprising, an input terminal receiving an audio signal, a band elimination filter connected to said input terminal and removing a selected band of audio frequencies from said audio signal, an intermittent source of audio signals having frequency components in said selected band, a rectifier connected to said intermittent source to develop a control signal when said intermittent signal is present, a solenoid connected to said rectifier, a switch connected in parallel with said band elimination filter and controlled by said solenoid so that said switch is open in the presence of said intermittent signal and a speaker connected to said intermittent source of audio signals and to the output of said band elimination filter.

Claim 3

A circuit according to claim 1 including a first resistor in parallel with said band elimination filter.

Claim 4

A circuit according to claim 2 including a second resistor in series between said speaker and said source of intermittent signals.

Claim 5

A circuit for eliminating a selected band of audio frequencies from an audio spectrum and inserting another audio signal into said selected band comprising, an input terminal receiving an audio signal, a low pass filter connected to said input terminal and removing a selected portion of audio frequencies from said audio signal, an intermittent source of audio signals having frequency components in said selected band, a rectifier connected to said intermittent source to develop a control signal when said intermittent signal is present, a solenoid connected to said rectifier, said low pass filter comprising a pair of series-connected resistors and a capacitor, a switch connected between said capacitor and ground, and controlled by said solenoid so that said switch is open in the presence of said intermittent signal, and a speaker connected to said intermittent source of audio signals and to the output of said low pass filter.

Claim 6

A circuit for eliminating a selected band of audio frequencies from an audio spectrum and inserting another audio signal into said selected band comprising, an input terminal receiving an audio signal, a low pass filter connected to said input terminal and removing a selected portion of audio frequencies from said audio signal, an intermittent source of audio signals having frequency components in said selected band, a rectifier connected to said intermittent source to develop a control signal when said intermittent signal is present, a solenoid connected to said rectifier, said low pass filter comprising a pair of series-connected resistors and a capacitor, a switch connected between said capacitor and ground, and controlled by said solenoid so that said switch is open in the presence of said intermittent signal, and a speaker connected to said intermittent source of audio signals and to the output of said low pass filter.

Claim 7

A circuit for eliminating a band of audio frequencies from a stereophonic audio signal and inserting an intermittent audio signal comprising, a left audio signal input terminal, a right audio signal input terminal, a pair of band elimination filters respectively connected to said left and right audio signal input terminals, first, second, third and fourth switchable amplifiers with the first and third respectively receiving the outputs of said pair of band elimination filters and the second and fourth respectively connected to said left and right audio signal input terminals, a left speaker connected to the outputs of said first and second switchable amplifiers, a right speaker connected to the outputs of said third and fourth switchable amplifiers, a switching circuit connected to said source of intermittent audio signal and connected to said first and third switchable amplifiers, a rectifier circuit receiving a portion of said intermittent audio signal to develop a control signal, the output of said rectifier circuit connected to said switching circuit such that said first and third switchable amplifiers pass signals when an intermittent audio signal is present and said second and fourth switchable amplifiers pass signals when said intermittent signal is abscent.

Claim 8

A circuit for eliminating a band of audio frequencies from a stereophonic audio signal and inserting an intermittent audio signal comprising, a left audio signal input terminal, a right audio signal input terminal, a pair of band elimination filters respectively connected to said left and right audio signal input terminals, first, second, third and fourth switchable amplifiers with the first and third respectively receiving the outputs of said pair of band elimination filters and the second and fourth respectively connected to said left and right audio signal input terminals, a left speaker connected to the outputs of said first and second switchable amplifiers, a right speaker connected to the outputs of said third and fourth switchable amplifiers, a switching circuit connected to said source of intermittent audio signal and connected to said first and third switchable amplifiers, a rectifier circuit receiving a portion of said intermittent audio signal to develop a control signal, the output of said rectifier circuit connected to said switching circuit such that said first and third switchable amplifiers pass signals when an intermittent audio signal is present and said second and fourth switchable amplifiers pass signals when said intermittent signal is abscent.

Claim 9

A circuit according to claim 5 including a high pass filter between said source of intermittent signals and said rectifier circuit.

Claim 10

A circuit according to claim 5 including a Schmidt circuit connected between said rectifier circuit and said switching circuit.

Claim 11

A sound signal changing circuit according to claim 1, wherein the band elimination filter is a high-pass filter.

Claim 12

A sound signal changing circuit according to claim 2, wherein said first resistor is variable.

Claim 13

A sound signal changing circuit according to claim 1, wherein said selected band of audio frequencies to be removed from said audio signal is a man''s vocal sound signal component.

Claim 14

A sound signal changing circuit according to claim 1, wherein said selected band of audio frequencies to be removed from said audio signal is a sound signal component of a musical instrument.

Claim 15

A sound signal changing circuit according to claim 1, including an amplifier connected between said rectifier and said intermittent source of audio signal.

Claim 16

A sound signal changing circuit according to claim 11, wherein said amplifier has a band pass response signal path for preventing howling.

Claim 17

A circuit according to claim 5, wherein said pair of band elimination filters remove a low frequency component for preventing howling.

Claim 18

A sound signal changing circuit according to claim 5, wherein said switching circuit has a time delay.