Acoustic Signal Filter Control for Variable Earpiece Loading
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Solution Overview
Problem
Audio output devices, such as telephones, face challenges in maintaining consistent sound quality and preventing damage due to varying acoustic loading conditions caused by different user positions and handling methods, which existing technologies fail to address effectively.
Innovation Solution
An apparatus comprising a filter, an audio output device, and a microphone, where a detector monitors the signal power changes between the filtered electrical input and the electrical output signals to adjust the filter settings, ensuring consistent acoustic output by compensating for changes in signal power, thereby maintaining sound quality and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the maximum amplitude of the acoustic signal is limited to avoid injuring a user or damaging components, then user safety and component protection are improved, but sound quality may deteriorate
Solution Approach 1:
The filter's frequency and gain settings are made dynamic rather than fixed. The system continuously monitors acoustic loading conditions and adjusts the equalization filter parameters in real-time to adapt to changing user positions and environmental conditions, allowing the system to maintain both safety limits and optimal sound quality across different operating scenarios
Solution Approach 2:
The system employs a feedback mechanism where the sensor measures acoustic pressure, converts it to a response data signal, compares it with the digital input signal, and uses this information to automatically adjust the equalization filter. This closed-loop control enables the system to compensate for amplitude limitations and maintain sound quality while operating within safe amplitude boundaries
2Manufacturing precision
If the acoustic output signal is controlled to provide a particular standard of sound quality, then sound quality is improved, but the system becomes sensitive to variations in user position and handling
Solution Approach 1:
The equalization filter transitions from a static configuration to a dynamic one that continuously adapts to acoustic loading conditions. By monitoring changes in acoustic pressure and adjusting filter parameters accordingly, the system maintains consistent sound quality whether the user holds the apparatus tightly or loosely, or changes position during use
Solution Approach 2:
The system changes the parameters of the equalization filter (frequency and gain) based on detected acoustic loading conditions. When the user changes their holding position or applies different force to the apparatus, the sensor detects the resulting acoustic pressure changes, and the filter parameters are adjusted to compensate, ensuring consistent sound quality across varying usage conditions
3Manufacturing precision
If a sensor and speaker are located proximately to an earpiece to perform active equalization, then sound quality control is improved, but device complexity increases
Solution Approach 1:
The speaker serves multiple functions: it acts as both the audio output device for delivering sound to the user and as a reference source for the sensor to measure acoustic pressure. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in device complexity while still enabling active equalization
Solution Approach 2:
The sensor acts as an intermediary that indirectly measures the acoustic loading conditions by detecting acoustic pressure changes in the earpiece vicinity. Rather than directly sensing user position or force applied, the system uses acoustic pressure as a mediator to infer loading conditions and adjust the equalization filter accordingly, simplifying the measurement approach
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 ensures consistent sound quality and prevents damage by dynamically adjusting the filter settings in response to changes in user position, maintaining performance across different usage conditions without noticeable reduction in sound quality or increased processing power.
Implementation Method 1
an audio output device configured to convert the filtered electrical input signal to an acoustic output signal
Implementation Method 2
a microphone configured to detect an acoustic signal and provide an electrical output signal corresponding to the detected acoustic signal
Data Source
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AI summary
An apparatus, method and computer program where the apparatus comprises: a filter configured to filter an electrical input signal and provide a filtered electrical input signal to an audio output device; an audio output device configured to convert the filtered electrical input signal to an acoustic output signal; a microphone configured to detect an acoustic signal and provide an electrical output signal corresponding to the detected acoustic signal; and a detector configured to receive the filtered electrical input signal provided to the audio output device as a first input and the electrical output signal provided by the microphone as a second input; wherein the detector is configured to detect a change in the signal power of the electrical output signal provided by the microphone relative to the filtered electrical input signal provided to the audio output device and, in response to the detection of the change in the signal power, provide a control signal to the filter to control the filter to compensate for the detected change in signal power.