Acoustic Signal Processing Stabilizing Virtual Sound Source Localization
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Solution Overview
Problem
Existing virtual surround systems experience a decrease in sound image localization effectiveness when the gain of one sound image localization filter becomes significantly small compared to another, leading to unstable positioning of virtual sound sources.
Innovation Solution
An acoustic signal processing device that performs transaural processing using head acoustic transmission functions to generate signals with attenuated components in specific frequency bands, and adds subsidiary signals to enhance the acoustic signals, stabilizing the sound image localization by adjusting levels and delaying signals to improve crosstalk correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transaural processing is performed using head acoustic transmission functions to generate acoustic signals for virtual sound sources, then sound image localization is achieved, but the feeling of localization decreases when the gain of one sound image localization filter becomes significantly small compared to another
Solution Approach 1:
The patent applies parameter changes by modifying the acoustic signals in specific frequency bands (first band and second band corresponding to notch frequencies in the head acoustic transmission function) to compensate for gain imbalances. When one speaker's gain becomes significantly small, the system adjusts parameters of the acoustic signal (attenuation in specific bands, addition of subsidiary signals) to maintain stable localization feeling across different listening conditions and speaker configurations
Solution Approach 2:
The patent introduces subsidiary signals as an intermediary element to stabilize the localization feeling. These subsidiary signals are added to the main acoustic signals and act as a mediator that compensates for the imbalance when one speaker's gain is significantly small, thereby maintaining the overall stability of the sound image localization without requiring direct adjustment of the primary acoustic signal paths
2Ease of operation
If the gain of sound image localization filter for one speaker is reduced, then the acoustic signal can be generated for the virtual sound source, but the localization effect deteriorates due to significant gain difference between speakers
Solution Approach 1:
The system performs parameter changes on the acoustic signals by applying specific attenuation in the first and second frequency bands (corresponding to notch frequencies) and adding subsidiary signals. This allows the system to maintain accurate localization feeling even when the gain of one speaker is significantly reduced, by compensating for the gain difference through signal processing rather than requiring equal speaker gains
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 solution effectively stabilizes the feeling of sound image localization even when the volume of one speaker is significantly small compared to another, maintaining accurate positioning of virtual sound sources.
Implementation Method 1
by using a first head acoustic transmission function between the first virtual sound source and one of both ears of a listener located at the listening position, which ear is located on a side away from the first virtual sound source, and by using a second head acoustic transmission function between the first virtual sound source and the other of the both ears of the listener
Data Source
AI summary
The present technology relates to an acoustic signal processing device, an acoustic signal processing method, and a program capable of improving a feeling of localization of a sound image at a position deviated leftward or rightward from a median plane of a listener. A transaural processing unit performs a predetermined transaural process for an input signal by using a sound source opposite side HRTF and a sound source side HRTF to generate a first acoustic signal, and a second acoustic signal containing attenuated components in a first band which is the lowest band, and a second band which is the second lowest band in a range of a predetermined first frequency or higher frequencies, in bands of appearance of notches in the sound source opposite side HRTF. A subsidiary signal synthesis unit adds a first subsidiary signal constituted by a component in a predetermined band of the second acoustic signal to the first acoustic signal to generate a third acoustic signal. The present technology is applicable to an AV amplifier, for example.