Virtual Loudspeaker Array for Dynamic Sweet Spot Tracking
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Solution Overview
Problem
Existing methods for reconstructing a sound field using multiple loudspeakers, such as stereophony, wave field synthesis, and ambisonics, are limited by the creation of a 'sweet spot' where the reconstruction is accurate, but deviate significantly outside this area, restricting the dynamic placement and movement of the desired reproduction area.
Innovation Solution
The method employs virtual focused sound sources generated by electroacoustic converters, controlled using wave field synthesis or ambisonics, arranged around a contour to create a dynamically adjustable 'sweet spot' within a target sound reinforcement area, allowing for accurate sound field reconstruction and adaptation to listener movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wave field synthesis or ambisonics is used to physically reconstruct a sound field, then manufacturing precision of the sound field is improved, but the area of accurate reproduction is limited to a sweet spot in the center of the loudspeaker arrangement
Solution Approach 1:
The patent applies local quality by creating different virtual sound source configurations for different spatial regions. Virtual focused sound sources are generated specifically within a defined target area, while other regions receive different acoustic treatment. This allows high-resolution sound field reconstruction to be concentrated in the desired listening area rather than attempting uniform coverage, thereby improving local reproduction accuracy without requiring the entire space to meet the same precision standards.
Solution Approach 2:
The patent implements dynamics by allowing the target sound reinforcement area to be dynamically repositioned and resized. The system can track listener movement and adjust the position of the sweet spot accordingly. Virtual sound sources are dynamically generated and moved to maintain accurate reproduction in the current target area, enabling the reproduction zone to adapt to changing listening conditions rather than being fixed in the center of the loudspeaker arrangement.
2Device complexity
If the loudspeaker arrangement is fixed, then device complexity is reduced, but adaptability to different listening positions and areas is worsened
Solution Approach 1:
The patent applies copying by creating virtual sound sources that replicate the acoustic characteristics of physical loudspeakers. Instead of moving physical loudspeakers to different positions, the system generates virtual focused sound sources through signal processing that mimic the behavior of physical sources at desired locations. This allows the system to adapt to different listening positions and target areas while maintaining a fixed physical loudspeaker arrangement, thereby achieving adaptability without the complexity of reconfigurable hardware.
3Ease of operation
If stereophonic techniques are used to create a spatial sound impression, then ease of operation is improved, but manufacturing precision of the sound field is worsened because only an illusion is created without physical reconstruction
Solution Approach 1:
The patent introduces virtual focused sound sources as an intermediary between the physical loudspeakers and the listener's perception. These virtual sources are generated through signal processing and serve as a mediator that translates simple stereophonic input into physically reconstructed sound fields. The virtual sources act as an intermediate step that bridges the gap between easy-to-operate stereophonic techniques and high-precision sound field reconstruction, allowing the system to maintain operational simplicity while achieving accurate physical sound field reproduction in the target area.
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 approach enables precise and dynamic sound field reconstruction in a limited area, improving playback accuracy and flexibility, allowing the sweet spot to be tracked and adjusted according to listener position, while minimizing artifacts.
Implementation Method 1
using a plurality of electroacoustic converters (16) arranged on a contour (15)
Implementation Method 2
the virtual sound sources generate, by means of acoustic focusing, the desired sound field corresponding to a desired virtual sound source (1) within the area (3)
Implementation Method 3
the virtual sound sources generate, by means of acoustic focusing, the desired sound field
Data Source
Figure 1
Figure 2
Figure 3(a)~3(e)
AI summary
The method involves determining control signals (11) for virtual sound sources i.e. loudspeakers (14), for playback of sound fields at a mobile target sound area (3), where the sound sources are focused to a contour (13) surrounding the mobile target sound area. Loudspeaker control signals (12) for an electroacoustic transducer (16) are determined for producing the focused sound sources and for controlling the focused sound sources with the former control signals for the sound sources. The loudspeaker control signals are supplied to the electroacoustic transducer. An independent claim is also included for a device for playback of sound fields into a mobile target sound area.