Wave Field Synthesis Loudspeaker Array Artifact Reduction
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Solution Overview
Problem
Wave field synthesis systems with limited loudspeaker arrays suffer from artifacts due to the generation wave field, which interferes with the desired useful wave field, resulting in suboptimal audio reproduction, especially when virtual sources are positioned within or outside the loudspeaker array.
Innovation Solution
A method to reduce artifacts by determining relevant loudspeakers based on the virtual source's position and listener position, calculating drive signal components only for these relevant loudspeakers, and suppressing the generation wave field in areas where the listener is not, thereby reconstructing only the useful wave field for the listener.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wave field synthesis is implemented with a limited number of loudspeakers, then spatial sound reproduction is improved, but artifacts due to generation wave field occur
Solution Approach 1:
The loudspeaker array is segmented into multiple sub-arrays, each responsible for specific spatial regions. This segmentation allows selective activation of loudspeakers based on virtual source position and listener location, reducing unwanted generation wave fields while maintaining accurate spatial reproduction in the listener's area.
Solution Approach 2:
Different regions of the loudspeaker array are assigned different operational characteristics based on local requirements. Loudspeakers closer to the listener and virtual source are activated with appropriate delay and amplitude, while distant loudspeakers remain inactive or operate at reduced levels, creating local optimization of sound field quality.
2Area of stationary object
If all loudspeakers in the array are activated, then complete wave field coverage is achieved, but computation complexity and data transfer requirements increase
Solution Approach 1:
Instead of activating all loudspeakers in the array, only a subset of loudspeakers relevant to the current virtual source position and listener location are activated. This partial action reduces computation complexity and data transfer requirements while maintaining adequate wave field coverage in the listener's area.
Solution Approach 2:
The active loudspeaker configuration is dynamically adjusted based on the positions of virtual sources and listeners. As virtual sources move or listener positions change, the system selectively activates different subsets of loudspeakers, optimizing the balance between coverage area and computational complexity in real-time.
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 significantly reduces artifacts, providing artifact-free hearing enjoyment for listeners by selectively activating loudspeakers that contribute to the desired sound field, while deactivating those that generate unwanted interference, thus enhancing the overall audio experience.
Implementation Method 1
The basic idea of WFS is based on the application of Huygens' principle of the wave theory: Each point caught by a wave is starting point of an elementary wave propagating in spherical or circular manner.
Implementation Method 2
the radiating sound fields of the individual loudspeakers overlay correctly
Data Source
AI summary
In a wave field synthesis apparatus for driving an array of loudspeakers with drive signals, the loudspeakers being arranged at different defined positions, a drive signal for a loudspeaker being based on an audio signal associated with a virtual source having a virtual position with reference to the loudspeaker array and on the defined position of the loudspeaker, at first relevant loudspeakers of the loudspeaker array are determined on the basis of the position of the virtual source, a predefined listener position, and the defined positions of the loudspeakers, so that artifacts due to loudspeaker signals moving opposite to a direction from the virtual source to the predefined listener position are reduced. Downstream to means for calculating the drive signal components for the relevant loudspeakers and for a virtual source, there is means for providing the drive signal components for the relevant loudspeakers for the virtual source to the relevant loudspeakers, wherein no drive signals for the virtual source are provided to loudspeakers of the loudspeaker array not belonging to the relevant loudspeakers. With this, artifacts in an area of the audience room due to a generation wave field are suppressed, so that in this area only the useful wave field is heard in artifact-free manner.