Auditory Source Width Quantification via Binaural Signal Processing

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Solution Overview

Problem

Existing methods for assessing auditory spatial perception in sound systems, such as concert halls or home entertainment rooms, fail to accurately quantify the acoustic characteristics of a space in a way that aligns with human perception, as they rely on parameters like Clarity C80 and Interaural Cross-Correlation (IACC) that are position-dependent and do not fully capture the subjective experience of listener envelopment.

Innovation Solution

A system that estimates auditory source width by processing frequency-modulated noise signals using binaural recording devices and simulating human auditory processing, including head-related transfer functions and bandpass filtering, to determine the lateral width of binaural activity across sub-bands, providing a quasi-objective measure independent of measurement position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional monaural parameters (Clarity C80, Definition D50) are used to quantify spatial auditory characteristics, then measurement and calculation are simplified, but the parameters do not correlate with perceptible characteristics and fail to capture human auditory perception

Engineering Contradiction:

Improvemeasurement system complexityVSAvoidaccuracy of spatial perception quantification

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent transforms traditional monaural parameters into binaural parameters by incorporating interaural time differences (ITD) and interaural level differences (ILD). This parameter transformation enables the system to capture spatial auditory characteristics that correlate with human perception, specifically source width and listener envelopment, while maintaining measurement feasibility through objective binaural signal processing

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces binaural recording devices and head-related transfer functions (HRTF) as intermediaries between the sound field and measurement system. These intermediaries simulate human auditory processing, enabling objective quantification of spatial characteristics that align with subjective perception without requiring complex subjective listening tests

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If binaural parameters (Interaural Cross-Correlation IACC, Lateral Energy Fraction LEF) are used to quantify spatial auditory characteristics, then perceptible characteristics are better captured, but the parameters significantly depend on measurement position

Engineering Contradiction:

Improveaccuracy of spatial perception quantificationVSAvoidindependence from measurement position

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies head-related transfer functions (HRTF) as preliminary processing to the binaural signals before parameter extraction. This preliminary action pre-compensates for position-dependent effects by simulating how sound would reach the ears from different positions, thereby reducing the sensitivity of measured parameters to actual measurement position while maintaining accuracy in quantifying spatial characteristics

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extends traditional two-dimensional binaural parameter measurement into a three-dimensional spatial framework by incorporating directional information and spatial distribution of sound energy. This dimensional extension allows the system to characterize spatial attributes like source width and envelopment that are independent of specific measurement positions within the listening space

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Productivity

If established parameters (IACC, LEF) are used for ranking listener rooms, then objective comparison is enabled, but the ranking does not sufficiently match actual auditory perception and preferences of human listeners

Engineering Contradiction:

Improveefficiency of room assessmentVSAvoidalignment with human auditory perception

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the overall spatial perception into distinct objective components: source width (lateral extent of sound image) and listener envelopment (sense of being surrounded by sound). By segmenting these perceptual attributes and developing separate objective measures for each, the system enables efficient room ranking that aligns with human perception of different spatial qualities

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transforms traditional single-value binaural parameters into multiple spatial parameters that separately characterize source width and listener envelopment. This parameter transformation enables more nuanced and accurate assessment of spatial auditory characteristics, allowing room rankings to better reflect actual human auditory perception and preferences across different spatial dimensions

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8238589B2Objective quantification of auditory source width of a loudspeakers-room system

Publication Date: 2012.08.07 HARMAN BECKER AUTOMOTIVE SYST GMBH

AI summary

A source width estimation system may estimate an auditory source width of a sound. The system detects a first frequency modulated noise signal and a second frequency modulated noise signal. The detected noise signals may be processed to obtain an average value of a lateral width of a binaural activity over time and a plurality of sub-bands. The auditory source width of the noise signals may be determined from the average value of the lateral width of the binaural activity.