Audio Signal Processing Apparatus HRTF Convolution Localization
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Solution Overview
Problem
Current methods for enhancing surround effects in virtual sound images using two speakers are limited in effectively localizing sound images, failing to provide high-quality spatial audio experiences.
Innovation Solution
An audio signal processing apparatus that convolves multiple pairs of head-related transfer functions into stereo signals to localize sound images at different positions around a listener, using a control unit to generate processed signals for output to near-ear speakers, simulating virtual sound sources and adding reverb components to enhance spatial perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods using two speakers are used to create virtual sound images, then the system remains simple, but the surround effects and sound localization quality are insufficient
Solution Approach 1:
The patent divides the sound field into multiple discrete virtual sound image positions (front, rear, left, right) and processes each position separately using specific HRTF pairs. This segmentation allows precise control over sound localization at each position while maintaining overall system manageability through modular processing of individual directional components.
Solution Approach 2:
The patent extends conventional stereo processing by adding spatial dimension through multiple HRTF convolution layers. Instead of simple left-right channel processing, the system convolves signals with HRTFs corresponding to multiple spatial positions, creating virtual sound images in three-dimensional space around the listener, thereby adding directional and positional dimensions to the audio experience.
2Reliability
If multiple HRTF pairs are convolved into stereo signals, then surround effects are enhanced, but processing time and computational load increase
Solution Approach 1:
The patent performs HRTF convolution processing in advance during signal encoding or pre-processing stages, creating processed stereo signals with embedded virtual sound images. This preliminary action allows the computationally intensive convolution operations to be completed before playback, reducing real-time processing requirements and enabling high-quality surround effects during actual audio reproduction.
Solution Approach 2:
The patent combines multiple HRTF-processed signal components into integrated stereo outputs (processed L and R signals) that can be played back through conventional two-speaker systems. By merging the spatially processed components into standard stereo format, the system maintains compatibility with existing hardware while delivering enhanced surround effects, balancing quality with processing efficiency.
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
The apparatus achieves higher surround effects by creating a more immersive audio experience, allowing listeners to perceive sound as if it originates from multiple virtual sources outside their head, with clear localization and wide spatial sound fields.
Implementation Method 1
a first process of convolving two or more pairs of head related transfer functions which are a right-ear head related transfer function and a left-ear head related transfer function into the R signal
Implementation Method 2
convolving two or more pairs of head related transfer functions which are a right-ear head related transfer function and a left-ear head related transfer function into the R signal so that a sound image of the R signal is localized
Data Source
AI summary
An audio signal processing apparatus includes: an obtaining unit which obtains a stereo signal including an R signal and an L signal; a control unit which generates a processed R signal and a processed L signal by performing (i) a first process of convolving pairs of right- and left-ear head related transfer functions into the R signal so that a sound image of the R signal is localized at each of two or more different positions at a right side of a listener; and (ii) a second process of convolving pairs of right- and left-ear head related transfer functions into the L signal so that a sound image of the L signal is localized at each of two or more different positions at a left side of the listener; and an output unit which outputs the processed R signal and the processed L signal.