AUDIO PROCESSOR FOR ORIENTATION-DEPENDENT PROCESSING

• US 20160142843A1
• Filed: 01/20/2016
• Published: 05/19/2016
• 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
• Granted Patent: US 9,980,071 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 for hearing aids H04R25/43
• 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 for receiving at least two input audio channels, each input audio channel 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 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 the ear axis and the loudspeaker axis comprise an angle to each other, being greater than 0° and

lower than 180°

;

a mixer for mixing the two input audio channels to acquire two output channels depending on the position signal, such that

a portion of a second input audio channel being a right channel in a first output channel for a first angle between the ear axis and the loudspeaker axis is greater than a portion of the second input audio channel in the first output channel for a second angle between the ear axis and the loudspeaker axis, wherein the first angle is greater than the second angle or

a portion of a first input audio channel being a left channel in a second output channel for the first angle is greater than a portion of the first input audio channel in the second output channel for the second angle, wherein the first angle is greater than the second angle; and

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

wherein the input interface is configured to receive an upper left channel as a third input audio channel and an upper right channel as a fourth input audio channel, wherein the mixing is performed such that a portion of the upper left channel in the first output channel is greater than the portion of the right channel, wherein the angle is between 0° and

90° and

the portion of the right channel in the second output channel is greater than the portion of the upper left channel, wherein the angle is between 0° and

90° and

a portion of the upper right channel in the first output channel is greater than the portion of the left channel, wherein the angle is between 90° and

180° and

the portion of the left channel in the second output channel is greater than the portion of the upper right channel, wherein the angle is between 90° and

180°

, or

wherein the input interface is configured to receive an upper channel, wherein he mixing is performed such that a portion of the upper channel in the first output channel is greater than the portion of the right channel, wherein the angle is between 0° and

90° and

the portion of the right channel in the second output channel is greater than the portion of the upper channel, wherein the angle is between 0° and

90° and

the portion of the upper channel in the first output channel is greater than the portion of the left channel, wherein the angle is between 90° and

180° and

the portion of the left channel in the second output channel is greater than the portion of the upper channel, wherein the angle is between 90° and

180°

, or

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

, the first output channel 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 the second output channel 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 the left channel as the first input audio channel, the right channel as the second input audio channel and the upper channel as a fifth input audio channel, wherein the mixer is configured to generate, for an angle equal to 90°

, the first output channel which comprises the fifth input audio channel, and the second output channel which comprises a combination of the first and second input audio channel.

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

a portion of the left channel in the first output channel is greater than a portion of the right channel, wherein the angle is between 0°

and 90°

, and

a portion of the right channel in the second output channel is greater than a portion of the left channel, wherein the angle is between 0° and

90°

, and

the portion of the right channel in the first output channel is greater than the portion of the left channel, wherein the angle is between 90° and

180°

, and

the portion of the left channel in the second output channel is greater than the portion of the right channel, wherein the angle is 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 or the portion of the first input channel in the second output channel or the portion of the first input channel in the first output channel or the portion of the second input channel in the second output channel 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 for adding a first processed first input audio channel and a third processed second input audio channel, and

a second adder 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 between 45°

and 135° and

the second and the third gain values increase between 45° and

135°

.

7. A electrical device comprising:

an audio processor according to claim 1;

the two loudspeakers; and

a detector for detecting the information on the position of the two loudspeakers with respect to the ear axis of the listener and 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 input audio channel 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 the ear axis and the loudspeaker axis comprise an angle to each other, being greater than 0° and

lower than 180°

;

mixing the at least two input audio channels to acquire two output channels depending on the position signal, such that

a portion of a second input audio channel being a right channel in a first output channel for a first angle is greater than the portion of the second input audio channel in the first output channel for a second angle, wherein the first angle is greater than the second angle or

a portion of a first input audio channel being a left channel in a second output channel for the first angle is greater than the portion of the first input audio channel in the second output channel for the second angle, wherein the first angle is greater than the second angle; and

outputting the two output channels to the two loudspeakers,

wherein an upper left channel is received as a third input audio channel and an upper right channel is received as a fourth input audio channel, wherein the mixing is performed such that a portion of the upper left channel in the first output channel is greater than the portion of the right channel, wherein the angle is between 0° and

90° and

the portion of the right channel in the second output channel is greater than the portion of the upper left channel, wherein the angle is between 0° and

90° and

a portion of the upper right channel in the first output channel is greater than the portion of the left channel, wherein the angle is between 90° and

180° and

the portion of the left channel in the second output channel is greater than the portion of the upper right channel, wherein the angle is between 90° and

180°

, or

wherein an upper channel is received, wherein n the mixing is performed such that a portion of the upper channel in the first output channel is greater than the portion of the right channel, wherein the angle is between 0° and

90° and

the portion of the right channel in the second output channel is greater than the portion of the upper channel, wherein the angle is between 0° and

90° and

the portion of the upper channel in the first output channel is greater than the portion of the left channel, wherein the angle is between 90° and

180° and

the portion of the left channel in the second output channel is greater than the portion of the upper channel, wherein the angle is between 90° and

180°

, or

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

, the first output channel 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 the second output channel 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 are generated, or

wherein the input interface is configured to receive the left channel as the first input audio channel, the right channel as the second input audio channel and the upper channel as a fifth input audio channel, wherein the mixing is performed such that, for an angle equal to 90°

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

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