Speaker Port Occlusion Detection via Impedance-Based Gain Control
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Solution Overview
Problem
Audible distortion and user discomfort occur in portable electronic devices due to speaker port occlusion when users grip or prop the devices in a way that blocks the speaker port, causing shifts in resonance frequency and turbulence.
Innovation Solution
A system and method that detects changes in speaker resonance frequency by calculating impedance curves and adjusts the amplifier gain in real-time to correct audible distortion, using impedance curve models generated from test audio signals and temperature measurements to compensate for port occlusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the speaker port is blocked by user's hands or fingers, then the device can be gripped or propped, but audible distortion and user discomfort occur
Solution Approach 1:
The system continuously monitors the acoustic output of the speaker and detects changes in sound pressure level and frequency response that indicate port occlusion. When distortion is detected, the system provides feedback to adjust the audio signal in real-time, creating a closed-loop control system that maintains audio quality despite port blocking
Solution Approach 2:
The system dynamically changes audio parameters including gain levels, equalization filters, and signal routing when port occlusion is detected. By adjusting these parameters in response to detected conditions, the system compensates for the harmful effects of port blocking while allowing users to grip the device comfortably
2Reliability
If the speaker port is occluded, then the device can be held securely, but resonance frequency shifts and turbulence occur
Solution Approach 1:
The system uses real-time acoustic monitoring to detect resonance frequency shifts caused by port occlusion. The detected frequency changes feed back to the signal processing system, which adjusts equalization and filtering parameters to compensate for the instability and maintain consistent audio output characteristics
Solution Approach 2:
The system transitions from a static audio output system to a dynamic one that continuously adapts its parameters based on real-time detection of port occlusion conditions. The audio processing parameters are made variable and adjustable in response to changing operational conditions, allowing the system to maintain performance across different gripping scenarios
3Object-affected harmful factors
If real-time detection and correction of speaker port occlusion is implemented, then audible distortion is corrected, but device complexity increases
Solution Approach 1:
The system uses the existing speaker as both the audio output device and the sensing element for detecting port occlusion. The same acoustic transducer that produces sound also detects the changes in acoustic pressure and frequency response, eliminating the need for separate sensors and reducing overall system complexity
Solution Approach 2:
The system uses its own acoustic output as the basis for detecting port occlusion conditions. By monitoring the speaker's own performance characteristics and comparing them against expected values, the system performs self-diagnosis and self-correction without requiring external monitoring equipment or complex additional components
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 corrects audible distortion and user discomfort by dynamically adjusting amplifier gain to maintain optimal speaker performance despite port occlusion, while alerting the user through messages.
Implementation Method 1
outputting, from an amplifier to a speaker, a first audio signal
Implementation Method 2
calculating, by a processing system coupled to the amplifier, a first impedance curve for the speaker based on the first audio signal
Implementation Method 3
a housing for those portable electronic devices includes a speaker port through which air is moved by the speaker diaphragm of the speaker
Implementation Method 4
detecting, by the processing system, a change in a resonance frequency for the speaker based on an impedance curve model for the speaker and the first impedance curve for the speaker
Implementation Method 5
setting, by the processing system, a gain of the amplifier based on the detected change in the resonance frequency for the speaker
Data Source
AI summary
Features described herein generally relate to detecting and correcting audible distortion due to speaker port occlusion. Particularly, an audio signal is output, an impedance curve for the audio signal is calculated, a change in a resonance frequency for the speaker based on an impedance curve model for the speaker and the impedance curve for the speaker is detected, and a gain of the amplifier is set based on the detected change in the resonance frequency for the speaker.