# US 7,610,810 B2 · Methods for producing acoustic sources

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- Number: US 7,610,810 B2
- Document ID: US7610810B2
- Status: Granted
- Kind: B2
- Application number: 12/008,404
- Filed: 2008-01-10
- Published: 2009-07-16
- Granted: 2009-11-03
- Earliest claimed: 2008-01-10
- Assignees: ETS-Lindgren, Inc.
- Inventors: Douglas Frank Winker
- Web page: https://patentgrep.com/patent/US7610810B2

## CPC

- H04R 1/345: {for loudspeakers}
- 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

Embodiments include an acoustic source for use in a hemi-anechoic chamber comprising a source assembly and a waveguide assembly for producing sound outside of a measurement hemisphere and channeling the sound into the measurement hemisphere. A waveguide end from which sound emanates is positioned close to the reflecting plane of the chamber and can approximate a point source.

## Claims

### Claim 1

A method for producing an acoustic source for use in a sound chamber having a reflecting plane and absorber-lined walls, comprising:
positioning a source assembly outside a measurement hemisphere;
coupling the source assembly to a waveguide that carries sound from the source assembly into the measurement hemisphere to emanate sound at a waveguide end; and
positioning the waveguide end from which sound emanates to be close to the reflecting plane and away from the absorber-lined walls of the chamber.

### Claim 2 (depends on 1)

The method of claim 1, wherein the height of the waveguide end above the reflecting plane is adjustable to vary the directivity of the source.

### Claim 3 (depends on 1)

The method of claim 1, wherein the source assembly is positioned on a wall that is lined with absorber.

### Claim 4 (depends on 1)

The method of claim 1, wherein the source assembly is positioned exterior to the chamber.

### Claim 5 (depends on 1)

The method of claim 1, wherein the source assembly is positioned on the reflecting plane.

### Claim 6 (depends on 5)

The method of claim 5, wherein the source assembly is covered with sound absorbing material.

### Claim 7 (depends on 1)

The method of claim 1, wherein the waveguide end is mounted near the center of the reflecting plane.

### Claim 8

An acoustic source for use in a sound chamber having a reflecting plane and absorber-lined walls, the acoustic source comprising:
a source assembly positioned outside a measurement hemisphere;
a waveguide assembly coupled to the source assembly that guides sound from the source assembly into the measurement hemisphere to emanate sound at a waveguide end positionable near the center of the reflecting plane and away from the reflecting plane by an amount less than a wavelength at a highest frequency of interest.

### Claim 9 (depends on 8)

The source of claim 8, wherein the waveguide assembly further comprises a height adjustment mechanism to adjust the height of the waveguide end away from the reflecting plane.

### Claim 10 (depends on 8)

The source of claim 8, wherein the waveguide assembly comprises two or more sections of waveguide coupled by couplers.

### Claim 11 (depends on 8)

The source of claim 8, wherein a waveguide outer diameter is about a fourth of the diameter of a throat of a compression driver of the source assembly.

### Claim 12 (depends on 8)

The source of claim 8, wherein the source assembly comprises a compression driver and adapter to channel the throat of the compression driver to a smaller diameter exit aperture of the adapter.

### Claim 13 (depends on 8)

The source of claim 8, wherein the opening of the waveguide end is small enough and close enough to the reflecting plane to substantially appear to be a point source.

### Claim 14 (depends on 8)

The source of claim 8, wherein the source assembly is positioned on a wall of the chamber.

### Claim 15

A method for producing an acoustic source for use in a sound chamber having a reflecting plane and absorber-lined walls, comprising:
positioning a source assembly outside a measurement hemisphere; the source assembly comprising a compression driver and adapter almost totally encompassed by sound absorbing material and with an exit aperture for coupling to a waveguide assembly;
coupling the source assembly to a waveguide assembly that guides sound from the source assembly into the measurement hemisphere to emanate sound at a waveguide end; and
positioning the waveguide end from which sound emanates to be an adjustable distance from the reflecting plane.

### Claim 16 (depends on 15)

The method of claim 15, wherein the source assembly is positioned on a wall that is lined with absorber.

### Claim 17 (depends on 15)

The method of claim 15, wherein the source assembly is positioned exterior to the chamber.

### Claim 18 (depends on 15)

The method of claim 15, wherein the source assembly is positioned on the reflecting plane.

### Claim 19 (depends on 15)

The method of claim 15, wherein the opening of the waveguide end is small enough and close enough to the reflecting plane to substantially appear to be a point source.