SYSTEM AND METHOD FOR IMPROVING HEADPHONE SPATIAL IMPRESSION

• US 20120020502A1
• Filed: 05/25/2011
• Published: 01/26/2012
• Est. Priority Date: 07/20/2010
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Adams, Robert
• Granted Patent: US 9,491,560 B2
• Time in Patent Office: Days
• US Class Current: 381/310
• CPC Class Codes: H04S 2420/01 Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]
• CPC Class Codes: H04S 7/304 For headphones

Abstract

A headphone system includes a headphone, a sensor, and a processor. The headphone may provide sound from virtual speakers to a listener via a plurality of sound paths that are filtered with a plurality of filters. The sensor may sense an angular velocity of a movement of the listener. The processor may receive the angular velocity and may calculate delays in the plurality of sound paths and filter coefficients for the plurality of filters based on the angular velocity, and insert the calculated delays in the plurality of sound paths and adjust the plurality of filters with the calculated filter coefficients.

Claims

1. A headphone system, comprising:

a headphone for providing sound from virtual speakers to a listener via a plurality of sound paths that are filtered with a plurality of filters;

a sensor for sensing an angular velocity of a movement of the listener; and

a processor for receiving the angular velocity,

wherein, in response to the received angular velocity, the processor is configured to;

calculate delays in the plurality of sound paths and filter coefficients for the plurality of filters based on the angular velocity, and

insert the calculated delays in the plurality of sound paths and adjust the plurality of filters with the calculated filter coefficients.

2. The headphone system of claim 1, wherein the movement is a head movement of the listener.

3. The headphone system of claim 2, wherein the processor is further configured to:

perform a leaky integration of the angular velocity to calculate a current head position of the listener with respect to a reference position,

calculate angles of incidence for the plurality of sound paths to ears of the listener, and

calculate the delays in the plurality of sound paths and the filter coefficients for the plurality of filters based on the angles of incidence.

4. The headphone system of claim 3, wherein the leaky integration drifts toward the reference position after a head rotation to reposition the listener'"'"'s head with respect to the virtual speakers.

5. The headphone system of claim 3, wherein the leaky integration holds an integrated value substantially constant for a predetermined time after a head rotation and thereafter drift toward the reference position to reposition the listener'"'"'s head with respect to the virtual speakers.

6. The headphone system of claim 3, wherein the leaky integration has a larger leak factor if a head rotation is small and a smaller leak factor if the head rotation is large.

7. The headphone system of claim 3, wherein the processor is configured to perform a non-linear transformation prior to the leaky integration.

8. The headphone system of claim 7, wherein the non-linear transformation includes a dead-band that is wider than an offset of the sensor.

9. The headphone system of claim 3, further comprising a gesture detector for detecting a head gesture which triggers a reset of the leaky integration.

10. The headphone system of claim 9, wherein the head gesture is a shake of the listener'"'"'s head.

11. The headphone system of claim 1, wherein the sensor includes a gyroscope.

12. A method for rendering sound from virtual speakers to a listener via a plurality of sound paths that are filtered with a plurality of filters, the method comprising:

receiving, by a processor, an angular velocity of a movement of the listener sensed by a sensor;

calculating, by the processor, delays in the plurality of sound paths and filter coefficients for the plurality of filters based on the angular velocity; and

inserting, by the processor, the calculated delays in the plurality of sound paths and adjusting, by the processor, the plurality of filters with the calculated filter coefficients.

13. The method of claim 12, wherein the movement is a head movement of the listener.

14. The method of claim 13, further comprising:

performing a leaky integration to calculate a current head position of the listener with respect to a reference position;

calculating angles of incidence for the plurality of sound paths to ears of the listener;

calculating the delays in the plurality of sound paths and the filter coefficients for the plurality of filters based on the angles of incidence.

15. The method of claim 14, wherein the leaky integration drifts toward the reference position after a head rotation to reposition the listener'"'"'s head with respect to the virtual speakers.

16. The method of claim 14, wherein the leaky integration holds an integrated value substantially constant for a predetermined time after a head rotation and thereafter drift toward the reference position to reposition the listener'"'"'s head with respect to the virtual speakers.

17. The method of claim 14, wherein the leaky integration has a larger leak factor if a head rotation is small and a smaller leak factor if the head rotation is large.

18. The method of claim 14, further comprising performing a non-linear transformation prior to the leaky integration, wherein the non-linear transformation includes a dead-band that is wider than an offset of the sensor.

19. The method of claim 14, further comprising detecting a head gesture which triggers a reset of the leaky integration.

20. The method of claim 12, wherein the sensor includes a gyroscope.