Compact Loudspeaker DSP for Crosstalk Cancellation
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Solution Overview
Problem
Compact loudspeaker systems struggle to produce a broad and stable acoustic image due to physical constraints and inadequate spacing between main and sub speakers, which limits their ability to simulate the optimal placement of sound sources, resulting in unsatisfactory performance for listeners in various seating positions.
Innovation Solution
A compact multi-driver loudspeaker system with a single enclosure employs digital signal processing methods, including time delay and specific driver configurations, to simulate the optimal placement of sub speakers relative to main speakers, effectively canceling interaural crosstalk and enhancing the psycho-acoustic image breadth, even with reduced physical dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If drivers are spaced farther apart to achieve optimal acoustic image breadth, then the acoustic image stability and breadth improve, but the enclosure size increases
Solution Approach 1:
The patent replaces the mechanical solution of physically spacing drivers apart with a digital signal processing solution. DSP techniques including time delay adjustment and phase manipulation create virtual acoustic separation, allowing drivers to be positioned close together physically while maintaining the acoustic effect of larger spacing. This substitutes electronic processing for mechanical arrangement.
Solution Approach 2:
The patent changes the temporal and phase parameters of audio signals to compensate for reduced physical driver spacing. By adjusting time delays and phase relationships between drivers, the system creates the acoustic perception of properly spaced drivers even when physical constraints prevent optimal mechanical separation.
2Volume of moving object
If drivers are positioned closer together for compact design, then the enclosure becomes more compact, but the acoustic image breadth and stability deteriorate
Solution Approach 1:
The patent substitutes digital signal processing for mechanical driver arrangement to overcome the limitations of compact spacing. DSP algorithms process the audio signals to create virtual acoustic separation, compensating for the reduced physical distance between drivers and restoring acoustic image stability without requiring larger physical separation.
Solution Approach 2:
The patent transitions from solving the spacing problem in the spatial dimension to solving it in the temporal dimension through DSP. By manipulating time delays and phase relationships, the system creates acoustic separation in time rather than requiring physical separation in space, effectively adding a temporal dimension to the solution.
3Stability of the object's composition
If traditional stereo speaker placement is used, then the acoustic image is broad, but the system complexity and setup difficulty increase
Solution Approach 1:
The patent merges multiple functions into a single compact enclosure. Instead of requiring separate left and right stereo speakers positioned at optimal distances, the invention integrates all necessary drivers and DSP processing into one unit, combining the functions of multiple speakers while maintaining acoustic image breadth through electronic processing.
Solution Approach 2:
The patent creates a universal loudspeaker system that can provide both compact form factor and broad acoustic image. The single enclosure design serves multiple functions: housing drivers, providing acoustic processing, and delivering wide soundstage, eliminating the need for multiple separate speakers and complex placement arrangements.
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 system achieves a surprisingly effective psycho-acoustically expanded image breadth, providing a stable and immersive listening experience regardless of the listener's location, by employing digital signal processing to compensate for the close spacing of drivers and orient them laterally, allowing for a more compact design while maintaining acoustic performance.
Implementation Method 1
a first loudspeaker driver 108LMS and a second loudspeaker driver 108RMS positioned on opposite lateral sides of the enclosure center EC
Implementation Method 2
employ digital signal processing methods, including time delay and specific driver configurations, to simulate the optimal placement of sub speakers relative to main speakers
Data Source
AI summary
A single enclosure multi-channel loudspeaker product 100 uses a novel signal processing system and method to achieve a surprisingly effective psycho-acoustically expanded image breadth by inter-aural crosstalk cancellation, in a manner which relies on a new method for cancellation of apparent sources of inter-aural crosstalk. In the commonly owned Polk® SDA™ (prior art) method, the optimal distance between stereo pair main and effect (SDA) loudspeakers was required to be substantially equal to the ear-to-ear width of a typical user's head. Compact SDA speaker system 100 employs digital signal processing generating selected time delays to acoustically simulate the optimal placement of an effects transducer relative to its main transducer for a physically compact configuration having each side's “main” transducer (e.g., 108LMS) spaced at less than 5.5 inches from the side's corresponding SDA (or effects) transducer (e.g., 108LSS), and this permits the system enclosure to be surprisingly compact, (e.g., width of as little as 341.2 mm).