SOUND SYSTEM FOR ESTABLISHING A SOUND ZONE

• US 20140348329A1
• Filed: 05/19/2014
• Published: 11/27/2014
• Est. Priority Date: 05/24/2013
• Status: Active Grant

• Current Assignee: Harman Becker Automotive Systems GmbH (Samsung Electronics Co. Ltd.)
• Original Assignee: Harman Becker Automotive Systems GmbH (Samsung Electronics Co. Ltd.)
• Inventors: Christoph, Markus
• Granted Patent: US 9,338,554 B2
• Time in Patent Office: Days
• US Class Current: 381/17
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 5/00 Stereophonic arrangements stereophonic pick-ups H04R9/16, H04R11/12, H04R17/08, H04R19/10
• CPC Class Codes: H04S 1/007 in which the audio signals are in digital form data reduction aspects thereof based on psychoacoustics G10L19/02
• 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 3/008 in which the audio signals are in digital form, i.e. employing more than two discrete digital channels data reduction aspects thereof based on psychoacoustics G10L19/02
• CPC Class Codes: H04S 7/301 Automatic calibration of stereophonic sound system, e.g. with test microphone

Abstract

A system and method for acoustically reproducing k electrical audio signals (where k=2, 3, 4, . . . ) and establishing k sound zones are provided, in each of which one of k reception sound signals occurs that is an individual pattern of the reproduced and transmitted k electrical audio signals, comprising processing the k electrical audio signals to provide k processed electrical audio signals and converting the k processed electrical audio signals into corresponding k acoustic audio signals with k loudspeakers that are arranged at positions separate from each other and within or adjacent to the k sound zones. Each of the k acoustic audio signals is transferred according to a transfer matrix from each of the k loudspeakers to each of the k sound zones, where they contribute to the corresponding reception sound signals. Processing of the k electrical audio signals comprises inverse filtering according to three filter matrices, one of which is an i×i filter matrix, one is a j×j filter matrix and one is a k×k filter matrix, in which i, j<k. Each of the i×i and j×j filter matrices is configured to digitally process a share of the k electrical audio signals in a first frequency range or at a first sampling rate or both, or in a second frequency range or at a second sampling rate or both, respectively, and the k×k filter matrix is configured to digitally process all k electrical audio signals in a third frequency range or at a third sampling rate or both, the third sampling rate being the lowest of the three sampling rates and an upper frequency limit of the third frequency range being lower than upper frequency limits of the first frequency range and the second frequency range. The three filter matrices are configured to compensate for the transfer matrix so that each one of the reception sound signals corresponds to one of the electrical audio signals.

Claims

1. A sound system for acoustically reproducing k electrical audio signals (where k=2, 3, 4, . . . ) and establishing k sound zones, in each of which one of k reception sound signals occurs that is an individual pattern of the reproduced and transmitted k electrical audio signals, the system comprising:

a signal processing arrangement that is configured to process the k electrical audio signals to provide k processed electrical audio signals; and

k loudspeakers that are arranged at positions separate from each other and within or adjacent to the k sound zones, each configured to convert the k processed electrical audio signals into corresponding k acoustic audio signals;

where

each of the k acoustic audio signals is transferred according to a transfer matrix from each of the k loudspeakers to each of the k sound zones, where they contribute to the corresponding reception sound signals;

processing of the k electrical audio signals, which provides k processed electrical audio signals, comprises inverse filtering according to three filter matrices, one of which is an i×

i filter matrix, one is a j×

j filter matrix and one is a k×

k filter matrix, in which i, j<

k;

each of the i×

i matrix and j×

j filter matrix is configured to digitally process a share of the k electrical audio signals in a first frequency range or at a first sampling rate or both, or in a second frequency range or at a second sampling rate or both, respectively, and the k×

k filter matrix is configured to digitally process all k electrical audio signals in a third frequency range or at a third sampling rate, the third sampling rate being the lowest of the three sampling rates and an upper frequency limit of the third frequency range being lower than upper frequency limits of the first frequency range and the second frequency range; and

the three filter matrices are configured to compensate for the transfer matrix so that each of the reception sound signals corresponds to one of the electrical audio signals.

2. The system of claim 1, where k=2 n (where n=1, 2, . . . ) and the k electrical audio signals are configured to form n stereo signals and the n reception sound signals are configured to form k/2 binaural signals.

3. The system of claim 1, further comprising at least one of additional loudspeaker(s), additional sound zone(s), additional listening position(s) and matrices with increased dimensions.

4. The system of claim 1, where at least some of the loudspeakers are part of a group of loudspeakers, each group comprising at least two loudspeakers.

5. The system of claim 1, where the loudspeakers or the groups of loudspeakers are arranged in the roof liner or the head rest of a car cabin.

6. The system of claim 1, where the loudspeakers or the groups of loudspeakers are arranged around the position of a listener'"'"'s head.

7. The system of claim 1, where some of the listening positions are arranged in above or in front of front seats in a car cabin and one of the i×

i and j×

j matrices relates to these listening positions.

8. The system of claim 1, where at least one of the loudspeakers is a directional loudspeaker.

9. A method for acoustically reproducing k electrical audio signals (with k=2, 3, 4, . . . ) and establishing k sound zones in each of which one of k reception sound signal occurs that is an individual pattern of the reproduced and transmitted k electrical audio signals, the method comprising:

processing the k electrical audio signals to provide k processed electrical audio signals; and

converting the k processed electrical audio signals into corresponding k acoustic audio signals with k loudspeakers that are arranged at positions separate from each other and within or adjacent to the k sound zones;

where

each of the k acoustic audio signals is transferred according to a transfer matrix from each of the k loudspeakers to each of the k listening positions where they contribute to the reception sound signals;

processing of the two electrical audio signals, which provides k processed electrical audio signals, comprises inverse filtering according to three filter matrices, one of which is an i×

i filter matrix, one is an j×

j filter matrix and one is a k×

k filter matrix, in which i, j<

k;

each of the i×

i matrix and j×

j filter matrix is configured to digitally process a share of the k electrical audio signals in a first frequency range or at a first sampling rate or both, or in a second frequency range or at a second sampling rate or both, respectively, and the k×

k filter matrix is configured to digitally process all k electrical audio signals in a third frequency range or at a third sampling rate, the third sampling rate being the lowest of the three sampling rates and an upper frequency limit of the third frequency range being lower than upper frequency limits of the first frequency range and the second frequency range; and

the three filter matrices are configured to compensate for the transfer matrix so that each one of the reception sound signals corresponds to one of the electrical audio signals.

10. The method of claim 9, where k=2 n (with n=1, 2, . . . ) and the k electrical audio signals are configured to form n stereo signals and the n reception sound signal are configured to form k/2 binaural signals.

11. The method of claim 9, further comprising at least one of additional loudspeaker(s), additional sound zone(s), additional listening position(s), and matrices with increased dimensions.

12. The method of any of claim 9, where the at least some of the loudspeakers are part of a group of loudspeakers, each group comprising at least two loudspeakers.

13. The method of claim 9, where the loudspeakers or the groups of loudspeakers are arranged in the roof liner or the headrest of a car cabin.

14. The method of claim 9, where some of the listening positions are arranged in, above or in front of front seats in a car cabin and one of the 4×

4 matrices relates to these listening positions.

15. The method of claim 9, where at least one of the loudspeakers is a directional loudspeaker.