Audio processor for orientation-dependent processing

• US 9,980,071 B2
• Filed: 01/20/2016
• Issued: 05/22/2018
• Est. Priority Date: 07/22/2013
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Leschka, Florian, Plogsties, Jan
• Primary Examiner(s): Zhang, Leshui
• Application Number:
  US15/002,047
• Publication Number:
  US 20160142843A1
• Time in Patent Office: 853 Days
• Field of Search: 381 1, 381300-311, 381 12, 381 80, 381 81, 381 85, 381332, 381333, 381334, 381 91, 381123, 381122, 381 26, 381119, 381120, 381 17- 23, 348480, 348482, 348484, 348 E5122, 348 E5123, 348 E5125, 348 E513, 353 15, 353 19, 700 94, 7351416, 704500
• CPC Class Codes: H04R 2400/03 Transducers capable of generating both sound as well as tactile vibration, e.g. as used in cellular phones
• CPC Class Codes: H04R 2420/01 Input selection or mixing for amplifiers or loudspeakers
• CPC Class Codes: H04R 2420/03 Connection circuits to selectively connect loudspeakers or headphones to amplifiers
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 3/04 for correcting frequency response
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S
• 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 2400/03 Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1 H04S2400/01 takes precedence
• 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 2400/13 Aspects of volume control, not necessarily automatic, in stereophonic sound systems
• 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 7/303 Tracking of listener position or orientation

Abstract

Audio processor having an input interface, a detector interface, a mixer and an output interface. The input interface receiving at least two input audio channels, each input audio channel being associated with a predetermined reproduction position of at least two loudspeakers on at least one loudspeaker axis. The detector interface receiving a position signal indicating an information on a position of the at least two loudspeakers with respect to an ear axis of a listener, wherein the ear axis and the at least one loudspeaker axis have an angle to each other, being greater than 0° and lower than 180°. The mixer mixing the at least two input audio channels to obtain the at least two output channels depending on the position signal.

Claims

1. An audio processor comprising:

an input interface configured for receiving at least two input audio channels, each of the at least two input audio channels being associated with a predetermined reproduction position of two loudspeakers on a loudspeaker axis being a shortest distance between the two loudspeakers;

a detector interface configured for receiving a position signal indicating an information on a position of the two loudspeakers with respect to an ear axis of a listener, wherein an angle is formed between the ear axis and the loudspeaker axis, the angle being greater than 0° and

lower than 180°

, wherein the position signal indicates the angle;

a mixer configured for mixing the at least two input audio channels to acquire two output channels depending on the position signal; and

an output interface configured for outputting the two output channels to the two loudspeakers,

wherein the input interface is configured to receive a left channel as a first input audio channel of the at least two input audio channels, a right channel as a second input audio channel of the at least two input audio channels, an upper left channel as a third input audio channel of the at least two input audio channels and an upper right channel as a fourth input audio channel of the at least two input audio channels, wherein the mixing is performed such that, when the angle has a value between 0° and

90°

, a portion of the upper left channel in a first output channel of the two output channels is greater than a portion of the right channel in the first output channel of the two output channels, and a portion of the right channel in a second output channel of the two output channels is greater than a portion of the upper left channel in the second output channel of the two output channels, and, when the angle has a value between 90° and

180°

, a portion of the upper right channel in the first output channel of the two output channels is greater than a portion of the left channel in the first output channel of the two output channels and the portion of the left channel in the second output channel of the two output channels is greater than a portion of the upper right channel in the second output channel of the two output channels, or

wherein the input interface is configured to receive a left channel as a first input audio channel of the at least two input audio channels, a right channel as the second input audio channel of the at least two input audio channels, and an upper channel as a third input audio channel of the at least two input audio channels, wherein the mixing is performed such that, when the angle has a value between 0° and

90°

, a portion of the upper channel in a first output channel of the two output channels is greater than the portion of the right channel in the first output channel of the two output channels and the portion of the right channel in a second output channel of the two output channels is greater than the portion of the upper channel in the second output channel of the two output channels and, when the angle has a value between 90° and

180°

, the portion of the upper channel in the first output channel of the two output channels is greater than the portion of the left channel in the first output channel of the two output channels and the portion of the left channel in the second output channel of the two output channels is greater than the portion of the upper channel in the second output channel of the two output channels, or

wherein the input interface is configured to receive a left channel as a first input audio channel of the at least two input audio channels, a right channel as a second input audio channel of the at least two input audio channels, an upper left channel as a third input audio channel of the at least two input audio channels, and an upper right channel as a fourth input audio channel of the at least two input audio channels, wherein the mixer is configured to generate, for the angle equal to 90°

, a first output channel of the two output channels which comprises in total a portion of more than 30% from the third input audio channel and more than 30% from the fourth input audio channel, and a second output channel of the two output channels which comprises in total a portion of more than 30% from the first input audio channel and more than 30% from the second input audio channel, or

wherein the input interface is configured to receive a left channel as a first input audio channel of the at least two input audio channels, a right channel as a second input audio channel of the at least two input audio channels, and an upper channel as a third input audio channel of the at least two input audio channels, wherein the mixer is configured to generate, for the angle equal to 90°

, a first output channel of the two output channels which comprises the third input audio channel, and a second output channel of the two output channels which comprises a combination of the first input audio channel and the second input audio channel.

2. The audio processor according to claim 1, wherein the input interface is configured to receive the left channel as the first input audio channel and the right channel as the second input audio channel, wherein

a portion of the left channel in the first output channel of the two output channels is greater than a portion of the right channel in the first output channel of the two output channels, when the angle has a value between 0°

and 90°

, and

a portion of the right channel in the second output channel of the two output channels is greater than a portion of the left channel in the second output channel of the two output channels, when the angle has a value between 0° and

90°

, and

the portion of the right channel in the first output channel of the two output channels is greater than the portion of the left channel in the first output channel of the two output channels, when the angle has a value between 90° and

180°

, and

the portion of the left channel in the second output channel of the two output channels is greater than the portion of the right channel in the second output channel of the two output channels, when the angle has a value between 90° and

180°

.

3. The audio processor according to claim 1, wherein the mixer is configured so that the portion of the second input channel in the first output channel of the two output channels or the portion of the first input channel in the second output channel of the two output channels or the portion of the first input channel in the first output channel of the two output channels or the portion of the second input channel in the second output channel of the two output channels is delayed with respect to the corresponding other portion.

4. The audio processor according to claim 1, wherein the mixer comprises a matrix processor comprising variable matrix elements, wherein the variable matrix elements are adapted based on the position signal.

5. The audio processor according to claim 4, wherein the matrix processor is configured to use complex matrix elements.

6. The audio processor according to claim 1, wherein the mixer comprises

a first adder configured for adding a first processed first input audio channel and a third processed second input audio channel, and

a second adder configured for adding a second processed first input audio channel and a fourth processed second input audio channel,

wherein the first processed first input audio channel is processed using a first processor comprising a first gain value,

wherein the second processed first input audio channel is processed using a second processor comprising a second gain value,

wherein the third processed second input audio channel is processed using a third processor comprising a third gain value,

wherein the fourth processed second input audio channel is processed using a fourth processor comprising a fourth gain value,

wherein the first and fourth gain values decrease for the angle having a value between 45°

and 135° and

the second and the third gain values increase for the angle having a value between 45° and

135°

.

7. A electrical device comprising:

the audio processor according to claim 1;

the two loudspeakers; and

a detector configured for detecting the information on the position of the two loudspeakers with respect to the ear axis of the listener and configured for generating the position signal which is coupled to the detector interface.

8. A method for audio processing, comprising:

receiving at least two input audio channels, each of the at least two input audio channels being associated with a predetermined reproduction position of two loudspeakers on a loudspeaker axis being a shortest distance between the two loudspeakers;

receiving a position signal indicating an information on a position of the two loudspeakers with respect to an ear axis of a listener, wherein an angle is formed between the ear axis and the loudspeaker axis, the angle being greater than 0° and

lower than 180°

°

, wherein the position signal indicates the angle;

mixing the at least two input audio channels to acquire two output channels depending on the position signal; and

outputting the two output channels to the two loudspeakers,

wherein a left channel is received as a first input audio channel of the at least two input audio channels, a right channel is received as a second input audio channel of the at least two input audio channels, an upper left channel is received as a third input audio channel of the at least two input audio channels and an upper right channel is received as a fourth input audio channel of the at least two input audio channels, wherein the mixing is performed such that, when the angle has a value between 0° and

90°

, a portion of the upper left channel in a first output channel of the two output channels is greater than the portion of the right channel in the first output channel of the two output channels, and the portion of the right channel in a second output channel of the two output channels is greater than a portion of the upper left channel in second output channel of the two output channels, and, when the angle has a value between 90° and

180°

, a portion of the upper right channel in the first output channel of the two output channels is greater than the portion of the left channel in the first output channel of the two output channels and the portion of the left channel in second output channel of the two output channels is greater than the portion of the upper right channel in second output channel of the two output channels, or

wherein a left channel is received as a first input audio channel of the at least two input audio channels, a right channel is received as a second input audio channel of the at least two input audio channels, and an upper channel is received as a third input audio channel of the at least two input audio channels, wherein the mixing is performed such that, when the angle has a value between 0° and

90°

, a portion of the upper channel in a first output channel of the two output channels is greater than the portion of the right channel in the first output channel of the two output channels and the portion of the right channel in a second output channel of the two output channels is greater than the portion of the upper channel in second output channel of the two output channels and, when the angle has a value between 90° and

180°

, the portion of the upper channel in the first output channel of the two output channels is greater than the portion of the left channel in the first output channel of the two output channels and the portion of the left channel in second output channel of the two output channels is greater than the portion of the upper channel in second output channel of the two output channels, or

wherein a left channel is received as a first input audio channel of the at least two input audio channels, a right channel is received as a second input audio channel of the at least two input audio channels, an upper left channel is received as a third input audio channel of the at least two input audio channels, and an upper right channel is received as a fourth input audio channel of the at least two input audio channels, wherein the mixing is performed such that, for the angle equal to 90°

, a first output channel of the two output channels which comprises in total a portion of more than 30% from the third input audio channel and more than 30% from the fourth input audio channel, and a second output channel of the two output channels which comprises in total a portion of more than 30% from the first input audio channel and more than 30% from second input audio channel are generated, or

wherein a left channel is received as a first input audio channel of the at least two input audio channels, a right channel is received as a second input audio channel of the at least two input audio channels, and an upper channel is received as a third input audio channel of the at least two input audio channels, wherein the mixing is performed such that, for the angle equal to 90°

, a first output channel of the two output channels which comprises the third input audio channel, and a second output channel of the two output channels which comprises a combination of the first input audio channel and second input audio channel, are generated.

9. A non-transitory digital storage medium having stored thereon a computer program comprising program code, wherein, when the program code is running on a computer or on a processor, the method according to claim 8 is executed.