Parametric virtual speaker and surround-sound system

• US 6,577,738 B2
• Filed: 05/07/2001
• Issued: 06/10/2003
• Est. Priority Date: 07/17/1996
• Status: Expired due to Term

• Current Assignee: Turtle Beach Corporation
• Original Assignee: American Technology Incorporated (Emerson Electric Company)
• Inventors: Croft, James J. III, Norris, Elwood G.
• Primary Examiner(s): Harvey, Minsun Oh
• Application Number:
  US09/850,523
• Publication Number:
  US 20010055397A1
• Time in Patent Office: 764 Days
• Field of Search: 381/77, 381/79, 381/82, 381/160
• US Class Current: 381/77
• CPC Class Codes: G10H 1/0091 Means for obtaining special acoustic effects combined with modulation G10H1/043
• CPC Class Codes: G10H 2210/301 Soundscape or sound field simulation, reproduction or control for musical purposes, e.g. surround or 3D sound; Granular synthesis
• CPC Class Codes: G10K 15/02 Synthesis of acoustic waves synthesis of speech G10L13/00
• CPC Class Codes: H04B 11/00 Transmission systems employing sonic, ultrasonic or infrasonic waves
• CPC Class Codes: H04R 2217/03 Parametric transducers where sound is generated or captured by the acoustic demodulation of amplitude modulated ultrasonic waves
• CPC Class Codes: H04R 5/02 Spatial or constructional arrangements of loudspeakers
• CPC Class Codes: H04S 1/002 Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution control circuits for electronic adaptation of the sound field H04S7/30
• CPC Class Codes: H04S 3/00 Systems employing more than two channels, e.g. quadraphonic H04S5/00, H04S7/00 take precedence
• CPC Class Codes: H04S 3/002 Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution control circuits for electronic adaptation of the sound field H04S7/30

Abstract

A system for generating at least one remote virtual speaker location in connection with at least a partial reflective environment in combination with an audio speaker for creating multiple sound effects including a virtual sound source from the reflective environment which is perceived by a listener as an original sound source, by generating a primary direct audio output by emitting audio compression waves toward a listener, and generating a secondary indirect audio output from at least one virtual speaker remote from the audio speakers, by emitting ultrasonic sound from at least one parametric speaker associated with the audio speakers and oriented toward at least one reflective environment which is remote from the audio speakers, thereby indirectly generating sound from a reflective environment which is perceived as a virtual speaker, and synchronizing the primary audio output of the audio speakers with a secondary audio output from the at least one virtual speaker such that the listener hears a plurality of sound effects from a plurality of directions.

Claims

1. A method for providing reinforced propagated sound from a virtual Speaker at a separate location from a sound source which originates the propagated sound, said method comprising the steps of:

a) emitting parametric ultrasonic output including modulated ultrasonic and audio frequencies from a parametric emitter along a primary direction of propagation;

b) orienting the primary direction of propagation toward a reflective environment having surface properties which enable substantial reflection of the ultrasonic output along a secondary direction comprising an indirect path to a listener; and

c) providing reinforced propagation of audio sound from the reflective environment comprising (i) a reflected audio component and (ii) a reflected ultrasonic component including the parametric ultrasonic output which decouples along the secondary direction within air to reinforce the reflected audio component, thereby developing a virtual speaker along the secondary direction with respect to the listener.

2. A method as defined in claim 1, further comprising the step of modifying frequency response of the reflected audio component by configuring the shape of the reflective surface in accordance with a predetermined frequency response.

3. A method as defined in claim 1, further comprising the step of modifying frequency response of the reflected audio component by configuring the absorption properties of the reflective surface in accordance with a predetermined frequency response.

4. Method in accordance with claim 1, further comprising the step of modifying the reflected audio output by preprocessing the modulated ultrasonic and audio frequencies to compensate for changes imposed on the reflected audio output as a result of the reflective surface.

5. A method in accordance with claim 4, wherein the modifying step is implemented to adjust for ultrasonic absorption at the reflective surface.

6. A method in accordance with claim 4, wherein the modifying step is implemented to adjust for audio absorption at the reflective surface.

7. A method in accordance with claim 4, wherein the modifying step is implemented to adjust for changes arising from surface configuration at the reflective surface.

8. A method in accordance with claim 4, wherein the modifying step is implemented to adjust for changes arising from nonuniform conversion of ultrasonic energy to audio output across the audio bandwidth at the reflective surface.

9. A method in accordance with claim 4, wherein the modifying step is implemented to adjust for changes arising from nonuniform conversion of ultrasonic energy to audio output across the audio bandwidth along the primary direction of propagation.

10. A method in accordance with claim 4, wherein the modifying step comprises equalization of audio amplitudes to adjust for changes arising from nonuniform conversion of ultrasonic energy to audio output across the audio bandwidth at the reflective surface.

11. A method in accordance with claim 4, wherein the modifying step is implemented to adjust for changes in reflected audio output arising from diffusion of ultrasonic energy at the reflective surface which reduces post reflection intensity of the ultrasonic component.

12. A method as defined in claim 1, further comprising the step of propagating a combined parametric sound column of ultrasonic and audio output from a first reflective surface to a second reflective surface, thereby generating a second virtual speaker which provides audio output which is time delayed from the first virtual speaker.