Dual Compression Driver With Annular Exit for High-Frequency Directivity
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Solution Overview
Problem
Existing dual compression drivers with circular exits suffer from loss of directivity control at high frequencies due to cross-modes excited at the entrance of the horn or waveguide, particularly in line arrays where larger exit diameters worsen high-frequency directivity control.
Innovation Solution
A dual compression driver design featuring annular exits is achieved by merging acoustic signals from two driver assemblies through radial channels in phasing plugs, which then radiate outward and merge into an annular pathway, allowing for improved directivity control via an annular exit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a circular exit is used in dual compression drivers, then the structure is simple and easy to manufacture, but directivity control is lost at high frequencies due to cross-modes excited at the horn or waveguide entrance
Solution Approach 1:
The patent transitions from a symmetric circular exit to an asymmetric annular exit configuration. The annular exit provides different dimensional characteristics in radial and axial directions, enabling improved directivity control at high frequencies while maintaining structural feasibility through the dual-driver symmetric arrangement.
Solution Approach 2:
The patent introduces a new dimensional configuration by using an annular exit instead of a circular one. This dimensional change allows the acoustic path to maintain a more consistent cross-sectional area, reducing cross-mode excitation and improving directivity control in the vertical plane for line array applications.
2Shape
If the acoustic path narrows to reach the exit and then widens again in the waveguide, then the circular exit structure is maintained, but unnecessary redundancy is created in sound wave propagation
Solution Approach 1:
The patent extracts the problematic narrowing and widening sections from the acoustic path by implementing a straight annular configuration. This removes the redundant volume where sound waves would unnecessarily compress and expand, reducing energy loss and improving efficiency while maintaining the desired exit geometry through the annular shape.
3Power
If a larger exit diameter is used, then more acoustic power is radiated, but high-frequency directivity control is worsened due to cross-modes at the horn or waveguide entrance
Solution Approach 1:
The patent segments the acoustic path into two separate annular pathways from two independent driver assemblies. This segmentation allows each driver to contribute to the overall acoustic power while the annular configuration of each pathway prevents cross-mode excitation, maintaining directivity control even with increased total radiating 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
The annular exit configuration enhances high-frequency directivity control and reduces unnecessary redundancy in sound wave propagation, providing improved sound pressure level and dynamic range while maintaining low distortion.
Implementation Method 1
a first motor assembly disposed about a central axis at a first end of the dual compression driver
Implementation Method 2
Acoustic signals from the first plurality of apertures merge with acoustic signals from the second plurality of apertures
Implementation Method 3
radiate radially outward to the annular pathway and through the annular exit
Data Source
AI summary
A dual compression driver includes first driver assembly and a second driver assembly each including a motor assembly disposed about a central axis, an annular diaphragm coaxial to and operably connected to each motor assembly, and a phasing plug coaxial to each diaphragm. Each phasing plug includes an input side oriented toward the diaphragm, an output side oriented away from the diaphragm, and a plurality of apertures extending therethrough. A hollow extension duct has a bottom end mounted to the phasing plug of the first driver assembly, wherein an inner surface of the extension duct and an outer surface of the second driver assembly form an annular pathway terminating at an annular exit of the dual compression driver. Acoustic signals from the first and second driver assemblies merge between the output sides of the phasing plugs and radiate radially outward to the annular pathway and through the annular exit.