Loudspeaker Device With Inclined Dipole Elements
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Solution Overview
Problem
Conventional loudspeaker systems fail to consistently reproduce a true stereo sound image across different setups and distances, with performance degrading as the distance between loudspeakers and the listener increases, especially in the frequency range from the resonance frequency up to 2.5 kHz.
Innovation Solution
The loudspeaker device incorporates additional elements arranged in close proximity to the primary elements, with specific angular orientations and low-pass filtering, to enhance the perceived stereo effect by functioning as a dipole, improving fidelity and consistency of the stereo image, particularly for frequencies up to 2.5 kHz, and allowing for restricted element dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional loudspeaker elements are added to improve stereo reproduction at distance, then the perceived stereo effect is improved, but the device complexity increases
Solution Approach 1:
The loudspeaker device is segmented into multiple functional groups: first and second loudspeaker elements for primary sound radiation, and third and fourth loudspeaker elements for enhanced stereo effect at distance. Each group serves a specific frequency range and spatial function, allowing the system to maintain stereo reproduction fidelity across different listening distances without requiring a completely redesigned system.
2Reliability
If loudspeaker elements are placed in close proximity to function as a dipole, then the stereo effect is improved for frequencies up to 2.5 kHz, but the area occupied by the elements is reduced
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement by inclining the axes of the loudspeaker elements at an angle φ (0°-±30°) relative to the horizontal plane. This angular orientation in the vertical dimension allows the elements to function as a dipole configuration for improved stereo effect while maintaining a compact horizontal footprint, effectively using vertical space to resolve the area constraint.
3Reliability
If low-pass filtering is applied to the third and fourth elements, then the high-frequency lobe patterns are preserved, but the frequency range reproduced by these elements is limited
Solution Approach 1:
Different frequency ranges are assigned to different loudspeaker element groups based on their spatial characteristics. The third and fourth elements, positioned for dipole operation, are low-pass filtered to handle primarily mid-range frequencies up to 2.5 kHz where they provide the stereo enhancement benefit. The first and second elements handle the full frequency range including high frequencies, ensuring that each element group operates in its optimal frequency band without compromising overall system versatility.
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 configuration enhances the stereo reproduction by increasing the distance at which a satisfactory stereo effect is maintained, improving fidelity and consistency across a wider frequency range without altering high-frequency lobe patterns, even in space-constrained applications.
Implementation Method 1
said first and second loudspeaker elements are arranged to radiate sound in a first direction of propagation, wherein said first and second loudspeaker elements are acoustically isolated and arranged to receive a first signal and a second signal, respectively, at least part of said first signal being in anti-phase relative to said second signal
Implementation Method 2
The centre of said third loudspeaker element is located such that a first axis, intersecting the centre of said first loudspeaker element and the centre of said third loudspeaker element, is inclined an angle φ relative to a horizontal plane. The centre of said fourth loudspeaker element is located such that a second axis, intersecting the centre of said second loudspeaker element and the centre of said fourth loudspeaker element, is inclined at an angle φ relative to a horizontal plane, φ being 0° - ± 30°. The signals to the said third and fourth elements are low-pass filtered
Data Source
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AI summary
The present invention relates to a loudspeaker device, comprising first and second closely located and individually acoustically isolated loudspeaker elements. The first and second elements are arranged to receive a first signal and a second signal, respectively, at least part of said first signal being in anti-phase relative to said second signal. The device further includes third and fourth loudspeaker elements, being located in close proximity to said first and second loudspeaker elements, respectively. The centre of said third loudspeaker element is located such that a first axis intersecting the centre of said first loudspeaker element and the centre of said third loudspeaker element is inclined an angle f relative to a horizontal plane, f being in the range 0° - + 30°, and the centre of said fourth loudspeaker element is located such that a second axis intersecting the centre of said second loudspeaker element and the centre of said fourth loudspeaker element is inclined at an angle cp relative to a horizontal plane, f being 0° - ± 30°. The first and second signals to said third and fourth loudspeaker elements, respectively, are low-pass filtered, the cut-off frequency of said low-pass filters being less than or equal to 2.5 kHz.