Speaker Feedback Enclosure for Safe Adaptive Acoustic Output
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Solution Overview
Problem
Handheld communication devices face challenges in providing maximum acoustic output in non-ideal ambient environments without exceeding safe sound levels, particularly under low-leak conditions, where the user may not apply sufficient force for optimal sound transmission.
Innovation Solution
A feedback system that dynamically adjusts the speaker output based on real-time sound pressure levels detected by a microphone, using a feedback enclosure to monitor and moderate the sound levels, ensuring they remain within safe thresholds by reducing or boosting the output as necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the speaker is designed to provide maximum acoustic output under sealed conditions, then the sound level is sufficient in high ambient noise environments, but the sound level may exceed safe thresholds when the device is not properly sealed against the user's ear
Solution Approach 1:
The patent implements a feedback system using a microphone to detect sound pressure levels generated by the speaker. The system continuously monitors the acoustic output and adjusts the speaker gain dynamically based on the detected sound pressure, preventing excessive sound levels while maintaining sufficient output in high ambient noise environments. This closed-loop feedback mechanism resolves the contradiction by adapting the acoustic output to actual usage conditions rather than relying on fixed design parameters.
Solution Approach 2:
The system transitions from a static acoustic design to a dynamic one by continuously adjusting the speaker gain based on real-time sound pressure detection. The gain adjustment is dynamic and adaptive, changing according to the actual seal condition and ambient environment, thereby maintaining safe sound levels while preserving maximum output capability when needed.
2Reliability
If hard limits are defined for sound levels under worst case sealed conditions, then safety is ensured, but maximum acoustic output is compromised under normal or low seal conditions
Solution Approach 1:
The feedback system replaces fixed hard limits with adaptive soft limits that adjust based on actual usage conditions. The microphone detects sound pressure levels, and the system dynamically adjusts the speaker gain to maintain safe levels while maximizing output when conditions permit. This eliminates the need to design for worst-case sealed conditions only, as the system adapts to actual seal quality and ambient noise levels in real-time.
Solution Approach 2:
The system changes the operating parameters of the speaker dynamically by adjusting the gain based on detected sound pressure levels. Rather than maintaining a fixed conservative setting, the gain parameter is continuously modified to optimize both safety and acoustic output according to actual usage conditions, resolving the contradiction between reliability and power.
3Ease of manufacture
If the device is designed to work at 8 N force for standard loudness measurement, then compliance with standards is achieved, but maximum acoustic level is lower than what is allowed by standards under 13 N force
Solution Approach 1:
The system enables the speaker to operate at different power levels dynamically based on actual usage conditions rather than being constrained to a single design point. The feedback mechanism allows the speaker to achieve higher acoustic levels when the seal condition warrants it (approaching 13 N equivalent performance) while maintaining compliance at standard measurement forces (8 N), effectively bridging the gap between standard compliance and maximum permitted output.
Solution Approach 2:
The system changes the acoustic output parameter dynamically based on detected sound pressure and seal conditions. This allows the speaker to comply with standard measurement requirements at 8 N force while also being capable of achieving higher acoustic levels up to the standard limits when used under optimal sealing conditions, effectively allowing operation across a range of performance levels rather than being locked to a single conservative setting.
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
This solution ensures that the speaker output is optimized for both safety and effectiveness, maintaining sound quality while preventing damage from excessive noise levels, even under varying usage conditions.
Implementation Method 1
measuring sound pressure levels detected by a microphone located in an enclosure for the communication device
Data Source
AI summary
The disclosure recites a feedback system and method for adjusting output sounds generated by a communication device. The feedback system comprises: a transducer; a microphone; and an enclosure for the communication device defining a first location for the placement of the transducer, a second location for the placement of the microphone adjacent to the transducer, a first port connecting the first location to a cavity located on a top side of the enclosure, a second port connecting the second location to the cavity. For the system, the first port connects to the cavity beside the second port.