Headphone Transducer Positioning for Personalized 3D Audio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for 3D audio virtualization in headphones are limited by inaccurate, non-personalized Head-Related Transfer Functions (HRTFs) and require complex, computationally intensive digital signal processing, leading to ineffective and power-hungry solutions that compromise audio quality and usability.
Innovation Solution
A system and method that derive a composite HRTF by combining Pinna-Related Transfer Function (PRTF) and remainder HRTF components, where PRTF is acoustically implemented using transducers positioned relative to the ear canal and remainder HRTF is electronically implemented, allowing for personalized and efficient 3D sound reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If model-based HRTF approaches are used, then device complexity is reduced, but measurement precision and personalization accuracy deteriorate
Solution Approach 1:
The HRTF is segmented into two distinct components: PRTF (Pinna-Related Transfer Function) that captures acoustical effects from pinnae and ear canals, and remainder HRTF that captures effects from head, shoulders, and torso. This segmentation allows each component to be optimized separately - PRTF through simple acoustic measurements and remainder HRTF through efficient electronic implementation.
Solution Approach 2:
The patent introduces an intermediary measurement system using in-ear microphones to capture actual acoustical effects in the user's ear canal. This intermediary device bridges the gap between model-based approaches and direct measurement, enabling personalized HRTF extraction through simple acoustic measurements rather than complex algorithms.
2Measurement precision
If measurement-based HRTF approaches are used, then measurement precision improves, but device complexity and ease of operation worsen
Solution Approach 1:
The measurement system is designed to be self-service and automatic. The in-ear microphones automatically capture acoustical effects when the user inserts the headphones, eliminating the need for manual measurement procedures. The system self-calibrates by measuring the transfer function directly in the user's ear canal without requiring user intervention or complex setup procedures.
Solution Approach 2:
The patent replaces complex mechanical measurement systems (such as acoustic chambers, positioning equipment, and manual measurement procedures) with simple electronic sensors (in-ear microphones) that automatically perform measurements. This substitution dramatically simplifies the measurement process while maintaining high precision.
3Adaptability or versatility
If conventional DSP-based 3D audio virtualization is used, then adaptability is maintained, but use of energy and device complexity increase
Solution Approach 1:
The patent replaces computationally intensive digital signal processing with a hybrid approach that uses simple acoustic measurements for PRTF extraction and efficient electronic filtering for remainder HRTF application. This substitution dramatically reduces processing power requirements while maintaining adaptability to various audio applications through software-based convolution.
Solution Approach 2:
The patent changes the fundamental parameters of HRTF implementation from full digital convolution to a hybrid acoustic-electronic approach. By extracting PRTF through simple acoustic measurements and implementing remainder HRTF through electronic filters, the system reduces computational complexity while preserving audio quality and application compatibility.
4Adaptability or versatility
If conventional DSP-based 3D audio virtualization is used, then adaptability is maintained, but productivity and loss of time worsen due to processing latency
Solution Approach 1:
The PRTF is pre-measured and stored in memory during a one-time initialization process. During actual audio playback, the system retrieves the pre-measured PRTF and applies it through simple convolution operations, eliminating the need for real-time complex processing. This preliminary action dramatically reduces latency while maintaining adaptability.
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
Enables realistic three-dimensional sound reproduction similar to high-performance loudspeaker systems with reduced processing power and complexity, preserving critical spatial cues and interaural differences, while being cost-effective and compatible with various audio applications.
Implementation Method 1
two or more transducers that are positioned such that a front plane of the transducer, the front plane of the transducer's diaphragm, the transducer's mechanical center or the transducer's acoustical center point are located 25 mm or more from a user's ear canal entrance
Implementation Method 2
Pinna-Related Transfer Function (PRTF), that includes the acoustical effects due to pinnae and ear canals
Implementation Method 3
Pinna-Related Transfer Function (PRTF), that includes the acoustical effects due to pinnae and ear canals
Data Source
AI summary
3D audio virtualization within headphone-type sound reproduction devices, comprises: deriving an HRTF, comprising a PRTF, that includes acoustical effects due to pinnae and ear canals, and a remainder HRTF, that includes acoustical effects due to head, shoulders, torso and other body parts while excluding acoustical effects from pinnae and ear canals; wherein the remainder HRTF is electronically implemented and omits acoustical effects due to pinnae and ear canal effects; and wherein the PRTF is acoustically implemented and personalized to the user through use of two or more transducers positioned such that a front plane of the transducer, the front plane of the transducer's diaphragm, the transducer's mechanical center or the transducer's acoustical center point are 25 mm or more from a user's ear canal entrance, and/or oriented so the 0° axis of acoustical output is aligned with the acoustical output axes of typical external loudspeakers positioned in the acoustical far-field.