# US 4,393,270 A · Controlling perceived sound source direction

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- Number: US 4,393,270 A
- Document ID: US4393270A
- Status: Granted
- Kind: A
- Application number: 06/153,903
- Filed: 1980-05-28
- Granted: 1983-07-12
- Earliest claimed: 1977-11-28
- Inventors: Johannes C. M. van den Berg
- Web page: https://patentgrep.com/patent/US4393270A

## CPC

- H04R 5/027: Spatial or constructional arrangements of microphones, e.g. in dummy heads
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)

## Abstract

An electronic signal representative of a sound is processed by applying different amplitude adjustments to the different components of the signal, these amplitude adjustments vary with frequency in a manner corresponding to the variation with frequency of the auditory response of a normal human listener for sounds impinging on him from a preselected direction of perception. When the electronic signal is converted into sound, the relationship of the amplitudes of the various components of the signal causes the listener to believe that the sound is impinging on him from the preselected direction.

## Claims

### Claim 1

A method of generating and processing electrical signals indicative of sound so that upon conversion of such signals into sounds and audition of such sounds by a normal human listener, such listener will perceive such sounds as emanating in preselected directions of perception from the listener, said method comprising the steps of:
(a) generating a plurality of signals each respectively from one of a plurality of directional microphones, each such microphone being predominantly responsive to sounds impinging on it in a unique one of a plurality of preselected directions of reception; and
(b) separately modulating each said electrical signal with a unique modulating signal indicative of a different one of said preselected directions of perception so that during such modulation different amplitude adjustments will be applied to different components of said signal, such adjustments varying with frequency in a manner corresponding to the variation of amplitude response with frequency of the normal human auditory system for sounds impinging on a listener from such one direction.

### Claim 2 (depends on 1)

A method as claimed in claim 1 in which said microphones are disposed in a geometrical arrangement corresponding to at least a portion of a spherical surface and the reception direction associated with each such microphone corresponds with its location in such arrangement.

### Claim 3 (depends on 1)

A method as claimed in claim 1 further comprising the step of converting said electrical signals after said modulation step.

### Claim 4 (depends on 1)

A method as claimed in claim 1 further comprising the step of recording said electrical signals after said modulation step.

### Claim 5

Apparatus for generating and processing electrical signals representative of emanating sounds comprising:
(a) a plurality of microphones for producing said electrical signals in response to sound incident thereon, each such microphone being predominantly responsive to sounds impinging on it in a unique one of a plurality of preselected directions of reception;
(b) a plurality of modulating means, each operatively connected to a distinct one of said microphones for modulating the signal produced thereby with a modulating signal indicative of a different one of a plurality of preselected directions of perception so that during such modulation different amplitude adjustments will be applied to different components of such one signal, such adjustments varying with frequency in a manner corresponding to the variation of amplitude response with frequency of the normal human auditory system for sounds impinging on a listener from such one direction.

### Claim 6 (depends on 5)

Apparatus as claimed in claim 5 in which said microphones are arranged in a spatial arrangement corresponding to at least a portion of a spherical surface, and the reception direction of each such microphone corresponds to its position in such spatial arrangement.