Acoustic Transducer Groups for High-Output Direct Field Acoustic Testing
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Solution Overview
Problem
Existing Direct Field Acoustic Testing (DFAT) systems are limited to maximum overall sound pressure levels (OASPL) of approximately 146.8 db, making Reverberant Acoustic Testing Facilities (RATFs) the only viable choice for higher levels, as previous attempts to increase OASPL in DFAT systems failed due to an incomplete understanding of the acoustic field and inadequate design of acoustic transducers.
Innovation Solution
A DFAT system with controllable controllers, microphones for input signals, and optimized groups of acoustical transducers that maximize acoustic power output per surface area to achieve OASPL of 149 db or higher, utilizing a combination of single input single output (SISO) or multiple input multiple output (MIMO) modes, and transducers optimized for different frequency ranges to maintain acoustic field characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If more acoustic transducers with greater maximum output are used to increase OASPL levels, then the acoustic output level is improved, but the system complexity and power requirements increase significantly
Solution Approach 1:
The patent changes the key parameter of acoustic transducer design by optimizing the ratio of maximum acoustic power output to radiating surface area. Instead of simply adding more transducers, the invention modifies the characteristics of existing transducers to achieve higher acoustic power density, thereby increasing OASPL without proportionally increasing system complexity
Solution Approach 2:
The patent creates acoustic transducers that can effectively operate across multiple frequency ranges by optimizing their design to complement the DFAT acoustic field characteristics. This multi-functionality allows a single transducer design to serve various testing requirements, reducing the need for numerous specialized transducers and thereby reducing system complexity
2Power
If the number of acoustic transducers is increased to achieve higher OASPL, then the acoustic output is improved, but the required facility volume increases
Solution Approach 1:
The patent changes the parameter of acoustic power density (power per unit surface area) by designing transducers with optimized radiating surfaces. This allows achieving higher total acoustic power output without proportionally increasing the radiating surface area, thereby maintaining compact facility volume while increasing OASPL capability
Solution Approach 2:
The patent uses computational models and simulations to predict and optimize the acoustic field characteristics before physical implementation. This virtual prototyping approach allows optimization of transducer arrangements and designs to achieve high acoustic power output in compact volumes without requiring extensive physical trial and error that would increase facility requirements
3Power
If acoustic transducers are designed for maximum power output, then the OASPL is improved, but the control stability and field uniformity deteriorate
Solution Approach 1:
The patent implements feedback control systems that continuously monitor the acoustic field and adjust transducer outputs to maintain stability and uniformity. The feedback mechanism allows the system to operate at high power levels while automatically correcting deviations, thereby achieving both high OASPL and control stability simultaneously
Solution Approach 2:
The patent optimizes the electrical and acoustic parameters of the transducers to achieve maximum power output while maintaining stable operation. By carefully selecting and tuning parameters such as impedance, resonance frequency, and drive voltage, the system achieves high acoustic power without sacrificing control stability
4Power
If acoustic transducers with greater maximum output are used, then the OASPL is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent develops a universal transducer design that can achieve high acoustic power output across different frequency ranges. This standardized design approach simplifies manufacturing by reducing the variety of specialized components needed, thereby lowering manufacturing complexity and cost while maintaining high OASPL capability
Solution Approach 2:
The patent achieves higher acoustic power output by optimizing existing transducer parameters rather than developing entirely new transducer types. By modifying parameters such as radiating surface area, voice coil configuration, and magnetic circuit design within conventional manufacturing capabilities, the system achieves high power output without proportionally increasing manufacturing complexity
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 system achieves OASPL levels of 149 db or higher with improved control of uniformity and coherence, reducing the need for larger volumes and increased power requirements, while maintaining reliability and efficiency.
Implementation Method 1
a plurality of acoustical transducers having a maximum acoustic power output such that the combined maximum acoustic output of the at least two acoustical transducers divided by the surface area of the radiating faces of the at least two acoustical transducers
Implementation Method 2
at least one microphone disposed in an appropriate location to provide at least one acoustical input signal
Data Source
AI summary
A direct field acoustic testing system comprising a control microphone, a controller operatively coupled to the control microphone such that the controller receives at least one input signal from the control microphone, and a plurality of acoustic transducer groups receiving an electronic signal from the controller, each transducer group including at least one acoustic transducer. An average power density of the direct field acoustic testing system for a pre-determined acoustic test spectrum being equal to or greater than 46 acoustic watts per square meter of total active acoustic transducer radiating surface area.