Wave Field Synthesis Level Correction for Loudspeaker Arrays
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Solution Overview
Problem
Wave field synthesis systems face challenges in maintaining consistent sound levels across a presentation region due to the use of a finite number of loudspeakers, leading to level artifacts, especially when virtual sources move or when there are holes in the loudspeaker array, resulting in uneven sound perception for listeners.
Innovation Solution
A level correction method is introduced that calculates a correction value based on the set amplitude state and actual amplitude state in the presentation region, using positional information of virtual sources and loudspeakers, to manipulate audio signals or component signals, ensuring consistent sound levels by adjusting the amplitude of signals emitted by individual loudspeakers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a finite number of loudspeakers is used in wave field synthesis, then the system complexity and cost are reduced, but level artifacts occur and sound level consistency deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the amplitude scaling factors of individual loudspeakers based on calculated correction values. The system modifies the signal parameters (amplitude levels) in real-time to compensate for the finite loudspeaker array, thereby maintaining sound level consistency without adding more physical loudspeakers.
Solution Approach 2:
The patent replaces the mechanical solution of adding more loudspeakers with a computational approach. By using wave field synthesis algorithms and level correction calculations, the system substitutes physical expansion with digital signal processing to achieve uniform sound distribution across the presentation region.
2Adaptability or versatility
If virtual sources move in the presentation region, then the spatial audio perception is improved, but level artifacts become more pronounced
Solution Approach 1:
The patent implements dynamics by continuously tracking the position of virtual sound sources and dynamically recalculating the level correction values as sources move. The system adapts the amplitude scaling factors in real-time based on the current positions of virtual sources, maintaining sound level consistency throughout the presentation region even when sources are in motion.
Solution Approach 2:
The patent employs feedback mechanisms by calculating the actual amplitude state in the presentation region based on virtual source positions and comparing it with the desired uniform distribution. The system uses this feedback information to continuously adjust the loudspeaker signal levels, eliminating level artifacts that would otherwise occur with moving virtual sources.
3Ease of manufacture
If holes are present in the loudspeaker array, then the system configuration is simplified, but uneven sound perception occurs
Solution Approach 1:
The patent compensates for holes in the loudspeaker array by dynamically adjusting the amplitude parameters of the remaining loudspeakers. The level correction algorithm calculates appropriate scaling factors for each active loudspeaker based on its position relative to the holes, ensuring uniform sound distribution despite the incomplete array 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 allows for consistent sound levels across the presentation region, eliminating level artifacts and maintaining the same volume perception for moving virtual sources, even with a limited number of loudspeakers, and provides a cost-effective solution for wave field synthesis systems.
Implementation Method 1
The basic idea of WFS is based on applying Huygens' Principle of Wave Theory: Every point detected by a wave is the starting point of an elementary wave propagating in a spherical of circular form.
Implementation Method 2
the audio signal of every loudspeaker have to be fed with a temporal delay and amplitude scaling so that the sound fields emitted of the individual loudspeakers are superimposed onto one another correctly
Data Source
AI summary
For a level correction in a wave field synthesis system having a wave field synthesis module and an array of loudspeakers for providing sound to a presentation region, a correction value which is based on a set amplitude state in a presentation region is determined, the set amplitude state depending on a position of the virtual source or a type of the virtual source, and the actual amplitude state in the presentation region depending on the component signals for the loudspeakers due to the virtual source. The correction value determined is fed to a manipulator manipulating the audio signal associated to the virtual source before feeding to the wave field synthesis module, or the component signals for the individual loudspeakers due to the virtual source are manipulated to reduce a deviation between a set amplitude state and an actual amplitude state at one point or several in the presentation region.