Parametric virtual speaker and surround-sound system

• US 20040247140A1
• Filed: 07/19/2004
• Published: 12/09/2004
• Est. Priority Date: 05/07/2001
• Status: Active Grant

• Current Assignee: Turtle Beach Corporation
• Original Assignee: American Technology Incorporated (Emerson Electric Company)
• Inventors: Croft, James J. III, Norris, Elwood G.
• Granted Patent: US 7,298,853 B2
• Time in Patent Office: Days
• 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 (12, 12, 14 or 15) 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 (53) 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 (24, 25 or 26) remote from the audio speakers, by emitting ultrasonic sound from at least one parametric speaker (20, 21 or 22) associated with the audio speakers and oriented toward at least one reflective environment which is remote from the audio speakers

Claims

1. A method for generating at least one remote virtual speaker location in connection with at least a partial reflective environment and in combination with an audio speaker for creating a plurality of sound effects including a virtual sound source from the reflective environment which is perceived by a listener as an original sound source, said method comprising the steps of:

a) generating a primary, direct audio output by emitting audio compression waves from audio speakers, thereby providing direct audio output to a listener;

b) generating 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 generally omni-directional sound from the reflective environment which is perceived as a virtual speaker; and

c) synchronizing the primary audio output of the audio speakers with the secondary audio output from the at least one virtual speaker such that the listener hears a plurality of sound effects from multiple directions.

2. A method as set forth in claim 1, comprising the further step of providing independent format wherein the primary audio output comprises at least one first channel, and the secondary audio output comprises at least one second, independent channel.

3. A method as set forth in claim 2, comprising the further step of providing a stereophonic format wherein the primary audio output includes two separate channels of stereophonic sound, and the secondary audio output comprises at least two channels of independent sound separate from the channels of the primary audio output.

4. A method as set forth in claim 1, comprising the additional step of positioning at least one virtual speaker at one of a) a side wall, b) a back wall, c) a ceiling surface, and d) a floor surface, of a room enclosure as the reflective environment.

5. A method as set forth in claim 1, further comprising the step of providing lateral movement of the at least one virtual speaker along the reflective surface to provide a sensation of motion for the listener.

6. A method as set forth in claim 1, comprising the additional steps of concurrently operating a video projection system in combination with the at least one virtual speaker and coordinating secondary audio output with events represented on a video display.

7. A method as set forth in claim 1, further comprising the steps of:

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 further steps of;

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

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

,

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.

8. A method as set forth in claim 7, further comprising the step of modifying frequency response of the reflected audio component by at least one of:

a) configuring the shape of the reflective surface in accordance with a predetermined frequency response; and

b) configuring the absorption properties of the reflective surface in accordance with a predetermined frequency response.

9. Method as set forth in claim 7, 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 reflection by the reflective surface.

10. A method as set forth in claim 9, wherein the modifying step is implemented to adjust for at least one of:

a) ultrasonic absorption at the reflective surface;

b) audio absorption at the reflective surface;

c) changes arising from surface configuration at the reflective surface;

d) changes arising from nonuniform conversion of ultrasonic energy to audio output across the audio bandwidth at the reflective surface;

e) changes arising from nonuniform conversion of ultrasonic energy to audio output across the audio bandwidth along the primary direction of propagation;

f) changes arising from nonuniform conversion of ultrasonic energy to audio output across the audio bandwidth at the reflective surface; and

g) changes in reflected audio output arising from diffusion of ultrasonic energy at the reflective surface which reduces post reflection intensity of the ultrasonic component.

11. A method as set forth in claim 7, 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.

12. A method as set forth in claim 1, further comprising the step of positioning the parametric emitter proximate to at least one of:

a) the audio speakers;

b) a video projection device; and

,

c) between the audio speakers and the virtual speaker.

13. A parametric sound system for providing multiple speaker locations around a listener with respect to a sound source location, said sound system including at least one parametric speaker having audio output generated in air from ultrasonic frequencies and being oriented toward at least one reflective surface which is remote from the sound source, said at least one parametric speaker providing secondary audio output along a path of reflective, parametric propagation for developing at least one virtual speaker remote from and electronically unconnected with the sound source.

14. A sound system as set forth in claim 13, further comprising a video projection device at the sound source, said sound source including synchronizing circuitry for coordinating the secondary audio output from the at least one parametric speaker with a visual display such that the listener sees and hears a coordinated enveloping sound audio-visual experience.

15. A sound system as set forth in claim 13, further comprising stereophonic circuitry coupled to audio speakers for providing at least one separate channel of stereophonic sound, said stereophonic circuitry being coupled to the at least one parametric speaker for providing at least one channel of stereophonic sound separate from the audio speakers.

16. A sound system as set forth in claim 13, wherein the parametric speaker includes a directional control driver for developing at least one interactive movable virtual speaker.

17. A sound system as set forth in claim 13, further comprising a second reflective surface positioned to receive propagated parametric output reflected from the first reflective surface to thereby generate at least two virtual speakers having a common parametric emitter source.

18. A method for distracting a person'"'"'s attention toward a remote location, by indirectly generating generally omni-directional sound at a remote virtual speaker source distant from the person, said generally omni-directional sound comprising at least one new sonic or subsonic frequency which corresponds to a difference between at least two interacting frequencies as part of a parametric speaker, said method comprising the steps of:

a) emitting ultrasonic frequencies which correspond to the at least two interacting ultrasonic frequencies to generate a parametric audio output which extends along a sound column toward a reflective surface which forms the remote virtual speaker;

b) reflecting the parametric audio output from the reflective surface to develop a new direction of propagation of the sound column; and

c) distracting the adversary'"'"'s attention toward the virtual speaker as an indicator of location for the individual.

19. The method of claim 18, wherein the person is an adversary.

20. A method for directing audio sound toward a location which is remote from an individual'"'"'s location and concealed around a corner of a physical structure by indirectly generating omni-directional sound at a remote virtual speaker source distant from the individual but along a common reflection surface, said omni-directional sound comprising at least one new sonic or subsonic frequency which corresponds to a difference between at least two interacting ultrasonic frequencies as part of a parametric speaker, said method comprising the steps of:

a) emitting ultrasonic frequencies which correspond to the at least two interacting ultrasonic frequencies to generate a parametric audio output which extends along a sound column toward the reflective surface which forms the remote virtual speaker; and

b) reflecting the parametric audio output from the reflective surface to develop a new direction of propagation of the sound column which is redirected around the corner of the physical structure.