Loudspeaker Active Directivity Control via Beamforming
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Solution Overview
Problem
Conventional box-shaped loudspeakers exhibit uncontrolled, frequency-dependent directivity characteristics, leading to diffuse sound and widened stereo images at low frequencies, which affects the listening experience, especially in home audio setups.
Innovation Solution
A speaker system with multiple transducers arranged around the enclosure and a processor that applies beamforming filters to control directivity, determining desired filter impulse responses at various frequency points and angles to generate targeted audio content, thereby minimizing diffraction effects and enhancing sound precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional box-shaped loudspeakers are used, then the device complexity is low, but the directivity control is poor leading to diffuse sound
Solution Approach 1:
The patent replaces mechanical directivity control methods (such as acoustic waveguides, horns, or physical speaker placement) with electronic signal processing. A processor applies beamforming filters to the audio signals before they reach the transducers, enabling precise control of sound directivity through electronics rather than mechanical means. This allows for frequency-dependent directivity control without adding complex mechanical structures.
Solution Approach 2:
The system dynamically adjusts filter parameters (impulse response, frequency response, phase, and amplitude) for each transducer based on the desired beamforming pattern. The processor modifies these parameters in real-time to control the directivity characteristics at different frequency points and angles, enabling precise control of sound propagation without changing the physical structure of the loudspeaker enclosure.
2Manufacturing precision
If beamforming filters are applied to control directivity, then sound precision is improved, but the processing complexity increases
Solution Approach 1:
The patent segments the audio signal processing into separate frequency points and angular directions. The system determines desired filter impulse responses at specific frequency points and generates target functions for different angles independently. This segmentation allows the complex beamforming process to be broken down into manageable computational steps that can be efficiently processed and implemented.
Solution Approach 2:
The system pre-calculates and stores filter impulse responses and target functions for various frequency points and angles before actual audio playback. This preliminary computation allows the processor to quickly retrieve and apply the appropriate filters during audio processing, reducing the real-time computational burden while maintaining high sound precision and directivity control.
Data Source
AI summary
A speaker system may include at least two transducers arranged within an enclosure and horizontally aligned with one another; and a processor configured to apply at least one filter to the transducers to generate beamforming audio content, the processor configured to receive input channels and determine a desired filter impulse response at a first frequency point of the input channels. The processor may also be configured to determine a frequency response of the desired filter impulse response at a first angle, and generate a target function based on the frequency response for application at the first angle.