Surround Audio Harmonic Addition Circuits for Bass Localization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing surround audio signal processing technologies lose the sense of localization of base sound when generating or downmixing multi-channel surround audio signals, leading to impaired spatial audio experience.
Innovation Solution
An audio signal processing device with harmonic addition circuits that add harmonic signals with a bass component as a fundamental tone to surround audio channels, adjusting gains based on directional characteristics to enhance localization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If virtual surround processing is applied to generate a stereo signal for headphones, then a sense of spacious sound field is created, but the sense of localization of base sound becomes insufficient
Solution Approach 1:
The patent applies parameter changes by adding harmonic signals with different frequency characteristics to the base sound channel. Specifically, it generates harmonic signals at frequencies that are integer multiples of the base sound frequency and adds them with adjusted amplitude ratios, thereby enriching the frequency spectrum while preserving localization cues through controlled parameter modification.
Solution Approach 2:
The patent introduces another dimension by adding harmonic frequency components to the audio signal. Instead of only processing the original frequency, it synthesizes and adds harmonic frequencies (2nd, 3rd, 4th harmonics, etc.), expanding the signal from a single frequency dimension to multiple frequency dimensions, which enhances both spaciousness and localization.
2Adaptability or versatility
If surround audio signal is generated from 2-channel stereo signal with emphasis on spaciousness, then a sense of spacious sound field is provided, but the sense of localization of base sound is impaired
Solution Approach 1:
The patent applies preliminary action by pre-processing the base sound channel before final output. It extracts the base sound, generates harmonic signals in advance, adjusts their amplitude ratios according to predetermined characteristics, and adds them to the original signal. This preliminary processing ensures localization cues are preserved while spaciousness is enhanced.
Solution Approach 2:
The patent modifies signal parameters by generating harmonic components at integer multiple frequencies of the base sound and controlling their amplitude ratios. This parameter change enriches the frequency spectrum for enhanced spaciousness while maintaining the fundamental frequency structure that carries localization information.
Data Source
AI summary
An audio signal processing device for processing a surround audio signal, includes a plurality of harmonic addition circuits corresponding to a plurality of channels, respectively, and configured to perform an operation on a first surround audio signal, where the plurality of channels forming at least some of channels constituting the first surround audio signal. The operation of each harmonic addition circuit of the plurality of harmonic addition circuits includes adding, to a signal of a channel of the first surround audio signal, a harmonic signal in a predetermined band having a bass component of the signal as a fundamental tone, and outputting the signal of the channel added with the harmonic signal, and forming a second surround audio signal by replacing at least the signal of the channel of the first surround audio signal with the signal of the channel added with the harmonic signal.