Headrest Audio System Binaural Filtering for Virtual Soundstage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional automobile audio systems are highly individualized to specific vehicle models and lack flexibility in sound presentation, often requiring multiple speakers to achieve a high-quality audio experience, which can be space-consuming and inefficient.
Innovation Solution
An audio system utilizing near-field speakers located in headrests, which up-mix and re-mix audio signals to simulate sound sources from virtual locations, enhancing sound presentation without the need for rear-seat speakers, using binaural filtering and component channel signals to control sound perception and location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple speakers are used to achieve high-quality audio presentation, then sound quality is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent uses binaural filters to create virtual sound sources that copy the acoustic characteristics of distant sound sources. By filtering audio signals through binaural filters derived from head-related transfer functions (HRTF), the system creates the perception of sound coming from specific locations without requiring physical speakers at those locations. This allows high-quality spatial audio presentation using only near-field speakers positioned close to the listener's head.
Solution Approach 2:
The patent replaces the mechanical approach of placing multiple physical speakers throughout the vehicle cabin with a signal processing approach. Instead of using far-field speakers positioned at various locations, the system uses near-field speakers combined with binaural filtering to achieve the same spatial audio effect. This substitution of mechanical speaker placement with acoustic signal processing reduces the number of required speakers while maintaining sound quality.
2Device complexity
If near-field speakers are used to reduce the number of speakers, then device complexity is reduced, but sound presentation quality may deteriorate
Solution Approach 1:
The patent changes the acoustic parameters of the near-field speaker output by applying binaural filters. These filters modify the frequency response, phase, and temporal characteristics of the sound to match the characteristics of sound coming from virtual far-field sources. By adjusting these acoustic parameters through signal processing, the system compensates for the inherent limitations of near-field speakers and achieves high-quality spatial sound presentation.
Solution Approach 2:
The patent introduces binaural filters as an intermediary between the audio source and the near-field speakers. These filters act as a mediator that transforms the audio signal to create the perception of sound coming from virtual locations. The binaural filters incorporate head-related transfer functions that simulate the interaction of sound with the listener's head, ears, and torso, thereby enhancing the realism of the spatial audio presentation despite the physical proximity of the speakers.
3Ease of operation
If binaural filtering is applied to create virtual sound sources, then soundstage control is improved, but processing complexity increases
Solution Approach 1:
The patent performs preliminary computation of binaural filters during system setup or calibration, storing the filter coefficients for later use. Instead of computing complex binaural transformations in real-time during audio playback, the system pre-calculates the filters based on the desired virtual speaker locations and the listener's head position. This preliminary action significantly reduces the processing complexity during actual operation, allowing for real-time soundstage control with minimal computational burden.
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 provides a cost-effective, high-quality audio experience with improved soundstage control and envelopment, allowing sound to appear from multiple locations without the need for additional physical speakers, optimizing space and enhancing the audio experience in small cars.
Implementation Method 1
filter the first binaural signal using the first binaural filter, the first filter causing sound produced by the near-field speakers to have characteristics at an intended position of a listener's head of sound produced by a sound source located at the first designated position
Data Source
AI summary
An automobile audio system having at least two near-field speakers located close to an intended position of a listener's head is configured by determining a first binaural filter that causes sound produced by each of the near-field speakers to have characteristics at the intended position of the listener's head of sound produced by a sound source located at a first designated position other than the actual locations of the near-field speakers, determining an up-mixing rule to generate at least three component channel signals from an input audio signal having at least two channels, and configuring the audio system to, determine a first binaural signal corresponding to a combination of the component channel signals originating at the first designated position, and filter the first binaural signal using the first binaural filter and to output the filtered signals using the near-field speakers.