Speaker Apparatus Multi-Unit Directivity Expansion
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Solution Overview
Problem
Speaker systems face challenges in providing a large audible range for high audio frequency bands due to the limited directivity angle of individual speaker units, which results in a narrower audible range and difficulty in listening to high-pitched sounds depending on the listener's position.
Innovation Solution
A speaker system configuration featuring a first speaker unit with a predetermined directivity angle, paired with second speaker units disposed opposite to each other vertically, having a greater directivity angle than the first unit, with equal distances from the center of the first unit to the second units, and both facing the same direction, ensuring the second units output sounds outside the first unit's directivity angle and maintaining a sum of sound pressure levels at 50% or less to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a single speaker unit is used to output high audio frequency sounds, then the directivity angle becomes smaller, but the audible range becomes narrower and sounds are difficult to listen to depending on listener position
Solution Approach 1:
The speaker system is divided into multiple speaker units (first speaker unit with smaller aperture and second speaker units with larger apertures) that operate in different frequency bands. The second speaker units handle frequencies where the first unit has poor radiation, while the first unit handles frequencies where the second units have poor directivity, creating complementary coverage that expands the overall audible range while maintaining good directivity characteristics.
Solution Approach 2:
The patent transitions from a single-speaker configuration to a multi-speaker spatial arrangement, adding dimensional complexity to the system. By positioning speaker units at different locations and orientations, the system achieves omnidirectional sound radiation capability that a single speaker unit cannot provide, thereby expanding the audible range without sacrificing directivity.
2Adaptability or versatility
If multiple speaker units with different apertures are used to expand audible range, then directivity angle improves, but device complexity increases
Solution Approach 1:
Multiple speaker units serve multiple functions simultaneously: the first speaker unit provides directed sound output for certain frequency ranges, while the second speaker units provide omnidirectional coverage for other frequency ranges. This multi-functionality allows the system to achieve expanded audible range without proportionally increasing complexity, as each unit contributes to multiple performance aspects.
Solution Approach 2:
Different speaker units are designed with different aperture sizes and directional characteristics optimized for specific frequency bands. The first speaker unit has a smaller aperture optimized for higher frequencies with better directivity, while the second speaker units have larger apertures optimized for lower frequencies with broader coverage. This local optimization allows the overall system to achieve wide audible range without requiring all units to be complex.
3Adaptability or versatility
If speaker units with different sound pressure levels are combined, then audible range expands, but interference and sound pressure level reduction occur
Solution Approach 1:
The patent carefully controls the sound pressure level parameter of the second speaker units relative to the first speaker unit. By setting the sound pressure level of the second units to be lower than that of the first unit, the system prevents interference and sound pressure level reduction while still achieving expanded audible range. This parameter optimization ensures reliable sound quality across the entire frequency spectrum.
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 directivity and achieves a large audible range in high audio frequency bands while maintaining high sound quality by preventing sound pressure level reduction and interference, ensuring composite sounds with high directivity and quality throughout the audio output band.
Implementation Method 1
The directivity angle of the speaker unit becomes smaller the higher the sound range of the same, and the audible range becomes narrower accordingly
Implementation Method 2
the sum of sound pressure levels of the pair of second speaker units is preferably 50% of a sound pressure level of the first speaker unit or less
Data Source
AI summary
A speaker system includes: a first speaker unit having a predetermined directivity angle in the horizontal direction; and a pair of second speaker units which are disposed opposite to each other with the first speaker unit sandwiched between them when viewed in the vertical direction and which have a directivity angle in the horizontal direction greater than the directivity angle of the first speaker unit, wherein distances from the center of the first speaker unit to the centers of the pair of second speaker units are equal to each other, and the first speaker unit and the pair of second speaker units are disposed so as to face toward the same direction.