Virtual Sound Source Generation Using HRTF Modulation
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Solution Overview
Problem
Current audio systems face challenges in providing an optimal height impression for users, particularly in formats like Dolby Atmos and DTS-X, as they require additional speakers or soundbars with limited sweet spots and aesthetic concerns, and existing solutions are not efficient in generating a realistic three-dimensional sound field.
Innovation Solution
An apparatus and method utilizing a loudspeaker arrangement that includes both virtual and real loudspeakers, controlled by circuitry to generate virtual sound sources and modulate soundfields using soundfield modulation functions, such as head-related transfer functions, to create the illusion of sound sources at predetermined positions, including above, below, or behind the listener.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional speakers are used to generate height impression, then the acoustic impression quality is improved, but the device complexity and aesthetic appeal deteriorate
Solution Approach 1:
The patent creates virtual copies of sound sources by processing audio signals through HRTF filters that simulate the acoustic characteristics of sounds originating from specific spatial positions. Instead of placing physical speakers at elevated positions, the system generates virtual sound sources that replicate the acoustic effect of such positions through signal processing, thereby achieving height impression without additional physical hardware
Solution Approach 2:
The patent replaces the mechanical approach of physically positioning speakers in three-dimensional space with an electronic signal processing approach. By using head-related transfer function (HRTF) filtering and binaural rendering, the system substitutes physical speaker placement with digital signal manipulation to create the perception of sounds from various spatial locations including above and below the listener
2Manufacturing precision
If speakers are placed at ceiling or floor positions, then the height impression is improved, but the ease of installation and aesthetic appeal worsen
Solution Approach 1:
The system creates virtual replicas of ceiling and floor speaker positions through signal processing. By applying appropriate HRTF filters to audio channels, the system generates the acoustic illusion that sound sources are located at elevated or depressed positions, eliminating the need for actual physical installation at these difficult-to-reach locations
Solution Approach 2:
The patent substitutes the mechanical installation of speakers at ceiling or floor mounts with an electronic rendering system. The complex mechanical task of installing speakers in hard-to-reach positions is replaced by digital signal processing that simulates the acoustic effect of such positioning, thereby dramatically simplifying installation while maintaining the desired spatial audio effect
3Device complexity
If sound-bars are used to reduce system complexity, then the device complexity is improved, but the acoustic uniformity and versatility deteriorate
Solution Approach 1:
The patent implements a universal audio rendering system that can generate virtual sound sources at any position in three-dimensional space using the same hardware configuration. The single loudspeaker arrangement equipped with HRTF-based binaural rendering can produce sounds from any direction and elevation, making the system as versatile as complex multi-speaker arrangements while maintaining simplicity
Solution Approach 2:
The system employs dynamic signal processing that adapts the audio output in real-time based on the desired virtual sound source position. By dynamically adjusting HRTF filter parameters and inter-channel time delays according to the target spatial location, the system achieves uniform acoustic quality across all virtual positions without requiring physical reconfiguration of hardware
Data Source
AI summary
The present disclosure pertains to an apparatus, which has circuitry configured to control a loud-speaker arrangement including at least one virtual loudspeaker and at least one real loudspeaker to generate at least one virtual sound source, wherein the at least one virtual sound source is generated based on contributions of the at least one virtual loudspeaker and the at least one real loudspeaker, and wherein a soundfield modulation function configured to generate an acoustic impression for a user is used to modulate a soundfield emitted by the virtual sound source, such that the acoustic impression is generated at a predetermined position.