Omnidirectional Compression Driver With Phasing Plug
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Solution Overview
Problem
Existing omnidirectional loudspeaker systems have low efficiency and sensitivity due to direct-radiating transducers, and horn systems with arrays of directional horns result in non-uniform coverage patterns and degraded performance.
Innovation Solution
A compression driver with a dome diaphragm and phasing plug that generates sound waves through an annular exit and radially expanding channels, creating a 360° radiation pattern, increasing efficiency and sensitivity while maintaining omnidirectional coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If direct-radiating transducers with conical or dome diaphragms are used, then omnidirectional sound radiation is achieved, but efficiency and sensitivity remain low (maximally a few percent)
Solution Approach 1:
The diaphragm is segmented into multiple sections (first section, second section, third section) with different acoustic impedances. Each section radiates sound independently, allowing the system to achieve omnidirectional radiation while improving overall efficiency by optimizing the acoustic properties of each segment.
Solution Approach 2:
Different sections of the diaphragm are assigned different local acoustic properties (acoustic impedances). The first section has a first acoustic impedance, the second section has a second acoustic impedance, and the third section has a third acoustic impedance. This local differentiation allows each region to contribute optimally to sound radiation, improving overall efficiency while maintaining omnidirectional coverage.
2Reliability
If arrays of directional horns are used, then sound radiation is achieved, but non-uniform coverage patterns and degraded performance occur due to cancellation regions
Solution Approach 1:
Multiple horn sections (first horn section, second horn section, third horn section) are merged into a single integrated omnidirectional horn structure. This unified design eliminates the cancellation regions that occur between separate directional horns while maintaining the ability to provide uniform 360-degree coverage, thereby improving reliability without requiring complex array configurations.
Solution Approach 2:
The horn structure employs curved, spherical geometry with a first spherical section, second spherical section, and third spherical section. This spherical configuration naturally provides omnidirectional radiation patterns and uniform coverage without the interference and cancellation issues inherent in planar horn arrays, achieving reliable uniform coverage with a simpler single-structure design.
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 solution achieves higher efficiency and sensitivity with uniform sound radiation across a full 360° coverage area, improving upon the limitations of direct-radiating transducers and horn systems by using a dome diaphragm and phasing plug configuration.
Implementation Method 1
a phasing plug having a bottom portion and a top portion, the bottom portion having a concave bottom surface disposed adjacent the convex surface of the diaphragm and defining a compression chamber therebetween
Data Source
AI summary
A compression driver for an omnidirectional loudspeaker includes a motor assembly and a dome diaphragm disposed coaxially above and operably connected to the motor assembly, the diaphragm having a convex surface and a concave surface. The compression driver includes a phasing plug having a top portion and a bottom portion having a concave bottom surface disposed adjacent the convex surface of the diaphragm and defining a compression chamber therebetween. The phasing plug includes a plurality of conduits extending through the bottom portion for sound waves to travel and converging to form an annular exit, the top portion including a plurality of radially expanding channels acoustically connected to the annular exit. Actuation of the diaphragm by the motor assembly generates sound waves within the compression chamber which travel through the annular exit and the radially-expanding channels to create a generally horizontal 360° radiation pattern of the sound waves from the compression driver.