Virtual Surround Loudspeakers with Constant Directivity
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Solution Overview
Problem
Traditional surround sound systems require multiple speakers placed around the listener, making them impractical for various setups, and existing virtual surround systems lack constant directivity across a wide range of frequencies, leading to reduced sound quality and complexity.
Innovation Solution
A virtual surround sound system using a combination of dipole beamforming, transducer directionality, and enclosure shading with multiple transducer arrays optimized for different frequency ranges, allowing for constant directivity and efficient sound production with fewer speakers, such as a single enclosure with side-firing transducers and front-firing transducers, and a controller for signal processing to create a wide frequency bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional surround sound systems use multiple speakers placed around the listener, then the surround sound experience is improved, but the system complexity and space requirements increase
Solution Approach 1:
The patent combines multiple speaker functions into a single enclosure by using dipole beamforming with multiple transducer arrays (front-firing and side-firing transducers) that work together to create virtual surround sound, eliminating the need for multiple separate speakers placed around the listener
Solution Approach 2:
The patent uses signal processing and beamforming algorithms as intermediaries to create virtual sound sources that appear to come from locations other than the physical speaker positions, enabling surround sound experience with front-placed speakers only
2Device complexity
If virtual surround systems use fewer speakers, then the system complexity is reduced, but the constant directivity across frequency ranges deteriorates
Solution Approach 1:
The patent divides the frequency spectrum into different bands and uses separate transducer arrays optimized for different frequency ranges (low-frequency array and high-frequency array), with each array maintaining constant directivity in its respective frequency range through dipole beamforming
Solution Approach 2:
The patent assigns different functions to different parts of the system: front-firing transducers handle direct sound reproduction while side-firing transducers create reflected sound paths, with each transducer type optimized for specific frequency ranges to maintain constant directivity locally
3Reliability
If dipole beamforming is used to create virtual surround, then the surround effect is improved, but the frequency range is limited due to radial lobes
Solution Approach 1:
The patent segments the frequency range into low-frequency and high-frequency bands, using dipole beamforming for low frequencies and transitioning to transducer directionality and enclosure shading for high frequencies to avoid radial lobe issues while maintaining surround effect
Solution Approach 2:
The patent changes the operational parameters of the transducer arrays based on frequency: using dipole beamforming configurations at low frequencies and relying on transducer directionality and enclosure shading at high frequencies, thereby extending the usable frequency range without radial lobe degradation
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 constant directivity across a wide range of frequencies, enhancing the surround sound experience by maintaining sound quality and reducing system complexity and size, while providing a more immersive audio experience with fewer speakers.
Implementation Method 1
dipole beamforming is one method for creating virtual surround using IID. Dipole pairs of transducers can be used to artificially increase the difference in sound level between the ears. The transducers in a dipole pair are driven out of phase with each other in order to create a null for certain frequencies or channels
Implementation Method 2
the speakers in the audio system then produce sound that converges at the listening position to properly create a surround sound experience for the listener
Data Source
AI summary
A speaker system includes a first array of transducers in a speaker enclosure and, and at least a second array of transducers in the speaker enclosure. The second array is a low-frequency array and the first array is a high-frequency array. The transducers in the first array are configured to have an operating frequency region covering at least the frequency ranges of the first array and the second array, and the transducers in the second are configured to have an operating frequency region covering at least the frequency ranges of the first array and the second array. The speaker system further includes an input port, and a controller operatively coupled with the input port. The controller is configured to provide an electronic-audio signal to the transducers such that the first array and the second array are tuned to different center frequencies and are a two stage dipole beamforming array.