Personalized Sound Virtualization via Individualized HRTF

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Solution Overview

Problem

Existing sound virtualization systems using generic head-related transfer functions (HRTFs) fail to provide an accurate external listening experience for users with unique head geometries or acoustic characteristics, as they do not account for individual differences in head shape and size.

Innovation Solution

A wearable audio device captures acoustic data from microphones near the user's ears to determine individualized HRTFs, adjusting audio playback to create a personalized sound virtualization experience by transforming generic HRTFs into individualized ones based on interaural time delay and spectral scattering characteristics, without requiring knowledge of environmental sound sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If generic HRTFs are used for sound virtualization, then the system is simple and works well for most users, but the accuracy of external listening experience deteriorates for users with unique head geometries

Engineering Contradiction:

Improvecompatibility across different usersVSAvoidaccuracy of external listening experience

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary acoustic measurements of the user's head geometry using microphones before audio playback begins. These measurements are used to calculate personalized HRTF parameters (interaural time delay, interaural level difference, spectral scattering) that are then applied to transform the audio signal, ensuring accurate sound virtualization tailored to each user's unique anatomy.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If personalized HRTFs are calculated using acoustic data from microphones, then the accuracy of sound virtualization improves, but the device complexity increases

Engineering Contradiction:

Improveaccuracy of external listening experienceVSAvoidcomplexity of HRTF calculation system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The audio device uses its own built-in microphones (already present for other functions like voice pickup or noise cancellation) to capture acoustic data for HRTF measurement. The device performs self-characterization by analyzing the acoustic signals received at different microphones to automatically calculate personalized HRTF parameters without requiring external measurement equipment or manual user input.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If manual measurement or additional hardware is used to determine HRTFs, then the precision of individualized parameters improves, but the ease of operation deteriorates

Engineering Contradiction:

Improveprecision of individualized HRTF parametersVSAvoidease of setup and user input

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The system automatically performs HRTF measurement and parameter calculation using its own microphones without requiring manual user input, external measurement equipment, or complex setup procedures. The device autonomously characterizes the user's acoustic environment and generates personalized HRTF data, making the process as easy as simply wearing the device.

Inventive Principle:

Principle #25Self-service

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 approach provides a more accurate and consistent spatial audio experience tailored to each user's physical characteristics, enhancing the listening experience without the need for additional user input or complex setup.

Implementation Method 1

acoustic data captured by microphones of a wearable audio device proximate to the left and right ears of the user

Methodology Applied

Scientific EffectAcoustic data capture: Sound

Implementation Method 2

first cross-correlating acoustic data captured by the microphones over a time period to determine time delay data over time

Methodology Applied

Scientific EffectCross-correlation:

Implementation Method 3

deriving and comparing spectral data from the acoustic data captured by the two microphones

Methodology Applied

Scientific EffectSpectral analysis:

Data Source

PatentUS20250097625A1Personalized sound virtualization

Publication Date: 2025.03.20 BOSE CORP

AI summary

A method for personalized sound virtualization is provided. The method includes measuring environmental sound using a first microphone of a wearable audio device. The first microphone is in or proximate to a right ear of a user. The method further includes measuring the environmental sound using a second microphone of the wearable audio device. The second microphone is in or proximate to a left ear of the user. The method further includes using acoustic data obtained from the measuring of the environmental sound via the first and second microphones, calculating individualized parameters, such as interaural time delay, relating to individualized HRTFs for the user. The method further includes using the individualized parameters to adjust audio playback by the wearable audio device. The audio playback may be adjusted at least partially based on an individualized HRTF generated by adjusting a generic HRTF according to the individualized parameters.