MULTICHANNEL SOUND REPRODUCTION METHOD AND DEVICE

• US 20130010970A1
• Filed: 09/28/2010
• Published: 01/10/2013
• Est. Priority Date: 03/26/2010
• Status: Active Grant

• Current Assignee: Harman Becker Automotive Systems Manufacturing Kft (Samsung Electronics Co. Ltd.)
• Original Assignee: Bang & Olufsen A/S
• Inventors: Pedersen, Jan Abildgaard, Hegarty, Patrick James
• Granted Patent: US 9,674,629 B2
• Time in Patent Office: Days
• US Class Current: 381/18
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04S 2400/05 Generation or adaptation of centre channel in multi-channel audio systems
• CPC Class Codes: H04S 2400/09 Electronic reduction of distortion of stereophonic sound systems
• CPC Class Codes: H04S 2400/11 Positioning of individual sound objects, e.g. moving airplane, within a sound field H04S2420/13 takes precedence
• 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 2420/05 Application of the precedence or Haas effect, i.e. the effect of first wavefront, in order to improve sound-source localisation
• 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 5/00 Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation
• CPC Class Codes: H04S 7/303 Tracking of listener position or orientation

Abstract

The present invention relates to a method for selecting auditory signal components for reproduction by means of one or more supplementary sound reproducing transducers, such as loudspeakers, placed between a pair of primary sound reproducing transducers, such as left and right loudspeakers in a stereophonic loudspeaker setup or adjacent loudspeakers in a surround sound loudspeaker setup, the method comprising the steps of (i) specifying azimuth angle range within which one of said supplementary sound reproducing transducers is located or is to be located and a listening direction; (Ii) based on said azimuth angle range and said listening direction, determining left and right interaural level difference limits and left and right interaural time difference limits, respectively; (iii) providing a pair of input signals for said pair of primary sound reproducing transducers; (iv) pre-processing each of said input signals, thereby providing a pair of pre-processed input signals; (v) determining interaural level difference and interaural time difference as a function of frequency between said pre-processed signals; and (vi) providing those signal components of said input signals that have interauial level differences and interaural time differences in the interval between said left and right interaural level difference limits, and left and right interaural time difference limits, respectively, to the corresponding supplementary sound reproducing transducer. The invention also relates to a device for carrying out the above method and systems of such devices.

Claims

1. A method for selecting auditory signal components for reproduction by means of one or more supplementary sound reproducing transducers, such as loudspeakers, placed between a pair of primary sound reproducing transducers, such as left and right loudspeakers in a stereophonic loudspeaker setup or adjacent loudspeakers in a surround sound loudspeaker setup, the method comprising the steps of:

(i) specifying an azimuth angle range within which one of said supplementary sound reproducing transducers is located or is to be located and a listening direction;

(ii) based on said azimuth angle range and said listening direction, determining left and right interaural level difference limits and left and right interaural time difference limits, respectively;

(iii) providing a pair of input signals for said pair of primary sound reproducing transducers;

(iv) pre-processing each of said input signals, thereby providing a pair of pre-processed input-signals;

(v) determining interaural level difference and interaural time difference as a function of frequency between said pre-processed signals; and

(vi) providing those signal components of said input signals that have interaural level differences and interaural time differences in the interval between said left and right interaural level difference limits, and left and right interaural time difference limits, respectively, to the corresponding supplementary sound reproducing transducer.

2. A method according to claim 1, wherein those signal components that have interaural level and time differences outside said limits are provided to said left and right primary sound reproducing transducers, respectively.

3. A method according to claim 1, wherein those signal components that have interaural differences outside said limits are provided as input signals to means for carrying out the method according to claim 1.

4. A method according to claim 1, wherein said pre-processing means are head-related transfer function means.

5. A method according to claim 1, further comprising determining the coherence between said pair of input signals, and wherein said signal components are weighted by the coherence before being provided to said one or more supplementary sound reproducing transducers.

6. A method according to claim 1, wherein the frontal direction relative to a listener, and hence the respective processing by said pre-processing means is chosen by the listener.

7. A method according to claim 1, wherein the frontal direction relative to a listener, and hence the respective processing by said pre-processing means is controlled by means of head-tracking means attached to a listener.

8. A device for selecting auditory signal components for reproduction by means of one or more supplementary sound reproducing transducers, such as loudspeakers, placed between a pair of primary sound reproducing transducers, such as left and right loudspeakers in a stereophonic loudspeaker setup or adjacent loudspeakers in a surround sound loudspeaker setup, the device comprising:

(i) specification means for specifying an azimuth angle range within which one of said supplementary sound reproducing transducers is located or is to be located, and for specifying a listening direction;

(ii) determining means that based on said azimuth angle range and said listening direction determine left and right interaural level difference limits and left and right interaural time difference limits, respectively;

(iii) left and right input terminals providing a pair of input signals for said pair of primary sound reproducing transducers;

(iv) pre-processing means for pre-processing each of said input signals provided on said left and right input terminals, thereby providing a pair of pre-processed input signals;

(v) determining means for determining interaural level difference and interaural time difference as a function of frequency between said pre-processed input signals; and

(vi) signal processing means for providing those signal components of said input signals that have interaural level differences and interaural time differences in the interval between said left and right interaural level difference limits, and left and right interaural time difference limits, respectively, to a supplementary output terminal for provision to the corresponding supplementary sound reproducing transducer.

9. A device according to claim 8, wherein those signal components that have interaural level and time differences outside said limits are provided to said left and right primary sound reproducing transducers, respectively.

10. A device according to claim 8, wherein those signal components that have interaural differences outside said limits are provided as input signals.

11. A device according to claim 8, wherein said pre-processing means are head-related transfer function means.

12. A device according to claim 8 further comprising coherence determining means determining the coherence between said pair of input signals, and wherein said signal components of the input signals are weighted by the inter-channel coherence between the input signals before being provided to said one or more supplementary sound reproducing transducers via said supplementary output terminal.

13. A device according to claim 8, wherein the frontal direction relative to a listener, and hence the respective processing by said pre-processing means is chosen by the listener,

14. A device according to claim 8, wherein the frontal direction relative to a listener, and hence the respective processing by said pre-processing means is controlled by means of head-tracking means attached to a listener or other means for determining the orientation of the listener relative to the set-up of sound reproducing transducers.

15. A system for selecting auditory signal components for reproduction by means of one or more supplementary sound reproducing transducers, such as loudspeakers, placed between a pair of primary sound reproducing transducers, such as left and right loudspeakers in a stereophonic loudspeaker-setup or adjacent loudspeakers in a surround sound loudspeaker setup, the system comprising at least two of the devices according to claim 8, wherein a first of said devices is provided with first left and right input signals, and wherein the first device provides output signals on a left output terminal (16), a right output terminal and a supplementary output terminal, the output signal on the supplementary output terminal being provided to a supplementary sound reproducing transducer, and the output signals on the left and right output signals, respectively, are provided to respective input signals of a subsequent device according to claim 8, whereby output signals are provided to respective of a number of supplementary sound reproducing transducers.