Hemispherical Loudspeaker Array With Bessel Driver Configuration
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Solution Overview
Problem
Conventional loudspeaker systems struggle to achieve uniform sound distribution in a hemisphere, leading to 'coloring' of sound frequencies depending on the listener's position, as existing techniques often work well for only a limited audio frequency range and compromise on sound pressure level and membrane size.
Innovation Solution
The loudspeaker apparatus divides the audio bandwidth into midrange and high-frequency parts, using a Bessel configuration for midrange drivers and angling tweeter drivers to create a symmetrical, uniform acoustic field, while woofer drivers provide a third field for low frequencies, ensuring consistent sound pressure across the hemisphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional loudspeaker systems use a single speaker or limited driver configuration, then the device complexity is reduced, but the uniformity of sound distribution across the hemisphere deteriorates, causing frequency spectrum variations (coloring) depending on listener position
Solution Approach 1:
The loudspeaker system is segmented into multiple independent driver units arranged in a vertical column, with each driver operating at a specific frequency range. The drivers are spaced at specific intervals and controlled with individual amplitude and phase adjustments based on Bessel function coefficients, enabling uniform hemispherical sound distribution across multiple frequency bands while maintaining manageable system complexity
Solution Approach 2:
The patent transitions from conventional horizontal speaker arrangements to a vertical column configuration, utilizing the vertical dimension to create omnidirectional hemispherical sound distribution. This dimensional change allows sound to radiate uniformly in all horizontal directions while maintaining consistent frequency response across the listening area
2Manufacturing precision
If loudspeaker drivers are arranged to achieve uniform hemispherical distribution, then the sound distribution uniformity is improved, but the device complexity increases due to multiple drivers with different amplitude and phase control requirements
Solution Approach 1:
The system employs parameter changes by applying Bessel function-based amplitude and phase adjustments to each driver in the vertical column. These parameter modifications create constructive and destructive interference patterns that cancel out directional preferences, achieving uniform omnidirectional hemispherical sound distribution while maintaining a relatively simple physical structure
Solution Approach 2:
Multiple identical or similar drivers are used across different frequency ranges (woofers, mid-range, tweeters), with each driver type performing the same omnidirectional radiation function. This universal approach allows the same Bessel configuration principle to be applied across the entire frequency spectrum, simplifying the overall system design while achieving comprehensive uniform sound distribution
3Area of stationary object
If the loudspeaker system covers a large listening area with uniform frequency coverage, then the area of coverage is improved, but the sound pressure level may be compromised due to energy distribution across multiple drivers
Solution Approach 1:
The frequency spectrum is segmented into multiple bands handled by different driver types (woofers for low frequencies, mid-range drivers for mid frequencies, tweeters for high frequencies). Each driver segment operates within its optimal frequency range, and the Bessel configuration ensures that energy from all segments combines constructively across the entire listening area, maintaining adequate sound pressure level while achieving uniform wide-area coverage
Solution Approach 2:
The system merges the acoustic output of multiple drivers operating at different frequency ranges into a unified omnidirectional hemispherical sound field. By carefully controlling the amplitude and phase of each driver according to Bessel function coefficients, the individual driver outputs combine to produce a cohesive sound field that maintains adequate sound pressure level across the entire listening area
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 approach balances sound quality by eliminating frequency spectrum variations, preventing audible beam forming, and allowing a large listening area with uniform frequency coverage, while also enabling a less obstructive design.
Implementation Method 1
a set of midrange drivers 6a, b, c, d, e, f, which are constructed in a Bessel configuration and are operable to generate a first acoustic field in the hemisphere
Implementation Method 2
a set of tweeter drivers 7a, b, c, d, which are adapted to generate a second acoustic field in the hemisphere
Implementation Method 3
a set of woofer drivers 5a, b, c, d, which are adapted to generate a third acoustic field
Data Source
AI summary
Loudspeaker apparatus comprise commonly some sort of casings or assemblies, in which one or more single speakers are integrated and which are used to convert electrical signals into sound. A loudspeaker apparatus 1 for radiating sound in a hemisphere is disclosed having a center axis 9, the loudspeaker apparatus 1 comprising: a set of midrange drivers 6a, b, c, d, e, f, whereby the midrange drivers 6a, b, c, d, e, f are controlled and/or arranged in a Bessel configuration and are operable to provide a first acoustic field in the hemisphere, a set of tweeter drivers 7a, b, c, d adapted to provide a second acoustic field in the hemisphere, whereby the first and the second acoustic field are respectively arranged symmetrically, whereby the main sound emitting directions of the single tweeter drivers 7a, b, c, d are angled to the center axis 9.