Vehicle Loudspeaker Focus System for Near-Head Sound Localization
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Solution Overview
Problem
Conventional surround sound systems, such as 5.1 or 7.1 systems, are unable to effectively reproduce auditory events that a listener perceives as being close to their head, and existing technologies like Wave Field Synthesis and Higher Order Ambisonics require a large number of loudspeakers, which are expensive and not suitable for all environments.
Innovation Solution
An apparatus and method that utilize a combination of a basic surround sound system and a focus sound system, where the focus sound system calculates filter values to generate focus group audio channels that allow for precise localization of sound near the listener's head, using a smaller number of loudspeakers and incorporating directional microphones and head tracking for improved sound placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of loudspeakers are used to create focused sources (Wave Field Synthesis), then sound localization precision near the listener's head is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the audio system into two independent parts: a basic surround sound system (5.1 or 7.1 channels) and a separate focused source system. The focused source system uses only a few additional loudspeakers (3-7) dedicated to creating focused sources, while the basic system handles general surround sound. This segmentation allows precise sound localization near the listener's head without requiring a complete WFS system with dozens of loudspeakers.
Solution Approach 2:
The patent makes the focused source system universally compatible with conventional surround sound systems. The same audio processor and rendering algorithms can handle both basic surround sound channels and focused source channels. The system can adapt to different configurations (5.1, 7.1, or other surround formats) while maintaining the focused source capability, making the solution universally applicable without requiring system-specific customization.
2Device complexity
If conventional surround sound systems are used, then device complexity is reduced, but the ability to reproduce close-distance auditory events is lost
Solution Approach 1:
The patent adds a dedicated focused source system as a separate functional segment to the conventional surround sound system. This segment includes specific loudspeakers (3-7 in number) and corresponding audio processing channels that are solely responsible for creating focused sources near the listener's head. The basic surround sound system remains unchanged, maintaining its simplicity while the added segment provides the missing close-distance sound reproduction capability.
Solution Approach 2:
The patent implements dynamic positioning of focused sources that can move independently from the basic surround sound field. The focused source system can dynamically create sound events at various positions around and near the listener's head, while the basic surround system maintains the overall spatial audio environment. This dynamic capability allows the system to adapt to different audio scenarios (speech, warnings, entertainment) without changing the physical speaker configuration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables the localization of sound sources near the listener's head, enhancing speech intelligibility and awareness in noisy environments, such as vehicles, without increasing overall volume or speaker size, thereby reducing distraction and improving safety.
Implementation Method 1
Wave Field Synthesis systems using a much larger number of loudspeakers than regular surround sound systems are able to position auditory events outside and even inside the room. The sources which are positioned inside the room are usually called 'focused sources' because they are calculated to focus sound energy at a specific spot located within the loudspeaker array.
Implementation Method 2
The audio signals for feeding the loudspeakers are either created during the production process by a mixer (e.g. motion picture sound track) or they are generated in real-time, e.g. in interactive gaming scenarios.
Implementation Method 3
The delay between those two systems is set such that the sound of the WFS speakers arrives at the listener position before the sound of the additional loudspeakers. This is done in order to use the precedence effect - the listeners will localize the source according to the sound of the WFS system with the higher localization resolution while the additional loudspeakers will help increase the perceived loudness without significantly affecting the localization perception of the sound source.
Data Source
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AI summary
The invention relates to an apparatus (6) and a method for driving loudspeakers (2.1, 3.1) of a sound system (1) in a vehicle (10), the sound system (1) comprising at least two loudspeakers (2.1) of a basic system (2), and a plurality of loudspeakers (3.1) of a focus system (3), wherein each of the loudspeakers (2.1, 3.1) of the basic system (2) and of the focus system (3) has a position in an environment (7), and wherein the apparatus (6) comprises : - a basic channel provider (6.1) for providing basic system audio channels (BSAC) for driving the loudspeakers (2.1) of the basic system (2), - a focused source renderer (6.2) for providing focus system audio channels (FSAC) to drive the loudspeakers (3.1) of the focus system (3), wherein the focused source renderer (6.2) is configured to calculate a plurality of filter values for the loudspeakers (3.1) of the focus system (3) based on the positions of the loudspeakers (3.1) of the focus system (3) and based on a position of a focus point (8, 8'), wherein the focused source renderer (6.2) is configured to generate at least three focus group audio channels (FGAC, FGAC-1 to FGAC-3) for at least some of the loudspeakers (3.1) of the focus system (3) based on the plurality of filter values and based on a focus audio base signal (FABS, FABS-1) to provide the focus system audio channels (FSAC), so that an audio output produced by the loudspeakers (3.1) of the focus system (3), when being driven by the focus system audio channels (FSAC), allows for localizing the position of the focus point (8, 8') by a listener (9) in the environment (7).