Loudspeaker Excursion Control With Multi-Band Attenuation
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Solution Overview
Problem
Loudspeakers are prone to mechanical stress and damage due to excessive excursion caused by high power audio signals, which existing technologies have not adequately addressed.
Innovation Solution
A method and system that split input signals into multiple frequency bands, allowing independent selection and application of power or excursion attenuation, using transformations between voltage and excursion domains, and incorporating lossy watermarks and clipper circuits to prevent damage without causing audible artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power audio signals are applied to loudspeakers, then sound output quality is improved, but mechanical stress and excursion damage occur
Solution Approach 1:
The system performs preliminary analysis of the audio signal to predict future excursion levels before they occur. By calculating predicted excursion values based on current and past signal characteristics, the system can proactively apply attenuation to prevent excessive excursion and potential damage before it happens.
Solution Approach 2:
The system implements a feedback mechanism where the actual excursion of the loudspeaker is monitored and compared against predicted excursion values. This feedback loop allows the system to dynamically adjust attenuation levels in real-time, ensuring that power delivery is optimized while preventing mechanical damage through continuous monitoring and adjustment.
2Reliability
If excursion attenuation is applied to prevent mechanical stress, then loudspeaker protection is improved, but audible distortion may occur
Solution Approach 1:
The system dynamically adjusts attenuation levels based on real-time signal characteristics and predicted excursion values. Rather than applying fixed attenuation, the system modulates the attenuation amount according to the instantaneous needs of the signal, maintaining audio quality while preventing excessive excursion. This dynamic approach ensures attenuation is applied only when and where necessary.
Solution Approach 2:
The system changes multiple parameters simultaneously including attenuation amount, frequency band distribution, and time constants based on the characteristics of the input signal. By dynamically adjusting these parameters, the system optimizes the balance between protection and audio quality, applying different attenuation strategies for different signal conditions to minimize audible distortion.
3Speed
If signal processing is performed in real-time to prevent excursion, then response time is improved, but computational complexity increases
Solution Approach 1:
The system divides the audio signal into multiple frequency bands and processes each band independently with different attenuation strategies. This segmentation allows complex protection logic to be applied in a modular fashion, reducing the computational burden on any single processing path while maintaining comprehensive protection across the full audio spectrum.
Solution Approach 2:
The system applies different levels of processing complexity to different frequency bands based on their susceptibility to excessive excursion. Rather than applying full computational complexity uniformly across all frequencies, the system focuses computational resources where they are most needed, using simpler processing for bands less prone to excursion issues while maintaining robust protection for vulnerable bands.
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
Effectively protects loudspeakers from excessive excursion by dynamically controlling power and excursion, reducing mechanical stress and preventing audible distortion, thereby extending the lifespan of loudspeaker components.
Implementation Method 1
When an electrical current is run through voice coil 104, the magnetic field in air gap 108 interacts with the current in coil 104 to create a force that causes bobbin 107 to move up or down
Data Source
AI summary
Systems and methods for loudspeaker protection against excessive excursion are described. In an illustrative, non limiting embodiment, a method may include splitting an input signal into two or more signals, each of the two or more signals within a given frequency band; independently selecting between a power attenuation or an excursion attenuation for each of the two or more signals; independently applying the selected power attenuation or excursion attenuation to each of the two or more signals; combining the attenuated two or more signals into an output signal; and providing the output signal to a loudspeaker.