Psychoacoustic Bass Enhancement in Loudspeaker Arrays
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Solution Overview
Problem
Conventional loudspeaker arrays face challenges in producing directional low-frequency sound due to physical limitations, such as small speaker size and close spacing, which affects beamforming efficiency and directivity, especially in portable devices with space constraints.
Innovation Solution
The method involves harmonically extending audio signals to produce higher frequency harmonics, which create a psychoacoustic illusion of bass, and spatially processing these signals to direct energy effectively using a loudspeaker array, combining psychoacoustic bass enhancement (PBE) with beamforming techniques to enhance low-frequency sound perception and directivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional loudspeaker arrays use small speakers with close spacing, then device size is reduced and portability is improved, but low-frequency beamforming efficiency and directivity deteriorate
Solution Approach 1:
The patent replaces the mechanical approach of using large physical speakers for low-frequency sound production with a signal processing approach. By harmonically extending mid-range audio signals to generate high-frequency harmonics and applying spatial processing techniques, the system creates the perception of bass sounds without requiring physically large speakers, thus resolving the contradiction between small device size and low-frequency beamforming efficiency
Solution Approach 2:
The patent changes the frequency parameters of the audio signal by harmonically extending mid-range signals to produce higher frequency harmonics. This parameter transformation allows the system to work around the physical limitations of small speakers while maintaining the perception of low-frequency sounds through psychoacoustic effects and spatial processing
2Volume of moving object
If small loudspeakers are used, then device compactness is improved, but the ability to reproduce low-frequency sound and resist damage from bass frequencies deteriorates
Solution Approach 1:
The patent substitutes the mechanical reproduction of low-frequency sounds by speaker cones with a signal processing system. By harmonically extending mid-range signals and using spatial processing, the system creates the perception of bass frequencies without physically reproducing them, thereby protecting small speakers from damage while maintaining audio quality
Solution Approach 2:
The patent introduces an intermediary signal processing layer between the audio source and the speakers. The harmonic extension and spatial processing modules act as intermediaries that transform the audio signal in a way that allows small speakers to produce the perception of bass sounds without being subjected to the physical stress of actual low-frequency reproduction
3Manufacturing precision
If harmonically extended signals are spatially processed, then low-frequency perception and directivity are improved, but signal processing complexity increases
Solution Approach 1:
The patent segments the audio signal processing into distinct functional modules: harmonic extension module, spatial processing module, and audio output stage. This segmentation allows each module to perform its specific function independently, making the overall complex system more manageable and implementable while achieving improved low-frequency directivity through coordinated operation of these modular components
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 allows for improved low-frequency sound reproduction and directivity in closely spaced loudspeaker arrays, enhancing the user experience by creating a perception of bass without the need for larger speakers, while reducing the burden on the original system and protecting small speakers from low-frequency damage.
Implementation Method 1
harmonically extending a second audio signal that includes energy in a first frequency range to produce an extended signal that includes harmonics, in a second frequency range that is higher than the first frequency range, of said energy of the second audio signal in the first frequency range
Implementation Method 2
Beamforming is a signal processing technique originally used in sensor arrays (e.g., microphone arrays) for directional signal transmission or reception. This spatial selectivity is achieved by using fixed or adaptive receive/transmit beampatterns.
Implementation Method 3
applying a corresponding one of a first plurality M of driving signals to a corresponding one of a first plurality M of loudspeakers of an array, wherein the driving signal is based on the imaging signal
Data Source
AI summary
Methods, systems, and apparatus for using a psychoacoustic-bass-enhanced signal to drive an array of loudspeakers are disclosed.