Virtual Loudspeaker Placement for Arbitrary Ambisonic Panning
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Solution Overview
Problem
Conventional ambisonic decoders perform poorly with arbitrary loudspeaker setups, particularly when loudspeakers do not fully encompass the listening position, limiting panning capabilities in 3D sound field representation.
Innovation Solution
The system modifies vector base amplitude panning (VBAP) by determining the placement of virtual loudspeakers within the loudspeaker setup, optimizing their placement and redistributing gains to ensure preservation of total energy, allowing for improved panning behavior in arbitrary setups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional ambisonic decoders are used with arbitrary loudspeaker setups, then the system can play back ambisonic content, but the panning performance deteriorates significantly when loudspeakers do not fully encompass the listening position
Solution Approach 1:
The patent introduces virtual loudspeakers as intermediary elements between the physical loudspeaker array and the ambisonic sound field. These virtual loudspeakers are positioned mathematically to complete the spherical enclosure around the listening position, even when physical loudspeakers are arranged in non-standard configurations. The virtual loudspeakers serve as mediators that bridge the gap between arbitrary physical setups and the requirements of conventional ambisonic decoding, enabling reliable panning performance without requiring optimal physical loudspeaker placement.
2Reliability
If virtual loudspeakers are added to arbitrary loudspeaker setups to improve panning, then panning capability improves, but the system complexity increases
Solution Approach 1:
The patent creates mathematical copies or representations of virtual loudspeakers that mirror the positions and functions of physical loudspeakers. These virtual loudspeakers are not physical components but rather computational representations that replicate the acoustic behavior needed for proper ambisonic decoding. By copying the functional role of physical loudspeakers in the virtual domain, the system achieves improved panning capability without adding physical complexity to the hardware architecture.
Solution Approach 2:
The patent transitions from a purely physical loudspeaker arrangement to a hybrid physical-virtual loudspeaker model by adding dimensional abstraction. Virtual loudspeakers are positioned in mathematical space rather than physical space, allowing the system to handle arbitrary physical configurations by mapping them to a standardized virtual spherical array. This dimensional shift enables improved panning performance while keeping physical hardware simple and unchanged.
3Reliability
If energy is preserved in the sound field during panning, then audio quality improves, but the calculation complexity increases due to gain redistribution requirements
Solution Approach 1:
The patent adjusts the gain parameters of virtual and physical loudspeakers dynamically during the panning process to maintain constant energy in the sound field. By changing the amplitude parameters of the virtual loudspeaker signals based on their relative positions and the desired pan trajectory, the system preserves audio energy while achieving smooth panning transitions. This parameter adjustment approach maintains audio quality without requiring complex computational overhead, as the gain redistribution follows straightforward mathematical relationships.
Data Source
AI summary
Placement of one or two placed virtual loudspeakers within a loudspeaker setup that includes a real loudspeakers is determined and vector base amplitude panning (VBAP) gains including the gains of the real loudspeakers and placed one or two virtual loudspeakers are also then determined. Gains of one or two placed virtual loudspeakers are redistributed to the real loudspeakers to ensure preservation of total energy. Real loudspeakers in the loudspeaker setup have redistributed gains of one or two placed virtual loudspeakers. Loudspeaker outputs are generated and transmitted to the real loudspeakers to be played back. When received audio content is ambisonics content, a predetermined grid is generated and HOA content is projected to the grid. Other aspects are also described.