Loud Hailing Array Directivity Control via Sliding High-Pass Filter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional loudspeaker devices are typically designed to be either directional or wide-spread, making it difficult to achieve both goals simultaneously, as dispersion is usually a fixed characteristic, limiting their ability to narrowly direct sound to a specific location or widely spread it to a large area.
Innovation Solution
A loud hailing device with a variable geometry transducer array and a sliding high-pass filter that allows control over the frequency range, enabling adjustable directivity by varying the low-frequency cutoff, which can be manipulated by an operator to achieve either a narrow or wide beam pattern depending on the application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the loudspeaker is designed to be directional with narrow beam spread, then the sound can be narrowly directed to a specific location or individual, but the coverage area is limited and cannot reach a large group
Solution Approach 1:
The patent implements dynamic control of the transducer array geometry, allowing the beam spread to be adjusted in real-time. The transducer array can change its configuration from a narrow beam pattern to a wide dispersion pattern, enabling the system to adapt between directional targeting and area coverage based on operational requirements
Solution Approach 2:
The system changes the physical parameters of the transducer array, specifically the spacing and arrangement of transducers, to control the acoustic beam pattern. By varying these geometric parameters, the device can transition between different directivity patterns, resolving the contradiction between narrow beam spread and wide coverage
2Adaptability or versatility
If the loudspeaker is designed to cover a wide area with wide dispersion, then the sound reaches a large group, but the sound cannot be narrowly directed to a specific individual
Solution Approach 1:
The system dynamically reconfigures the transducer array geometry to switch between wide dispersion patterns for area coverage and narrow beam patterns for targeted communication, allowing the same device to perform both functions as needed
3Ease of manufacture
If the device uses a fixed transducer array geometry, then the manufacturing is simpler, but the directivity control is limited and cannot be adjusted
Solution Approach 1:
The patent employs a movable or reconfigurable transducer array where elements can be positioned at different locations. This dynamic configuration capability allows the system to achieve variable directivity control while maintaining a relatively simple base structure that can be manufactured using standard techniques
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
Enables precise control over the directivity of the acoustic output, allowing the device to effectively target individuals or groups over varying distances while minimizing energy loss, enhancing speech intelligibility and range by optimizing low-frequency output.
Implementation Method 1
an array of transducers configured to provide a Bessel function output
Implementation Method 2
direct the acoustic waves along a relatively narrow path
Data Source
AI summary
A system and method for varying the directionality of an acoustic output of a loud hailing and warning device is disclosed. The method includes the operation of placing a sliding high-pass filter in a signal path of a transducer array having a frequency-dependant dispersion characteristic. A control is provided that varies a lower cutoff frequency of the sliding high-pass filter. The lower cutoff frequency of an electronic audio signal is variably controlled and sent to the transducer array to variably control the directionality of the acoustic output of the loud hailing and warning device.