Digital Audio Processor for Calibrated Hearing Exposure Control
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Solution Overview
Problem
Users of earphones or headphones lack knowledge of actual sound levels, leading to potential hearing damage due to unsafe audio exposure, as existing volume limiters do not account for earphone sensitivity or exposure duration, and noise-isolating earphones disconnect users from ambient sound cues.
Innovation Solution
A digital audio processor that measures and displays time-weighted average sound levels, provides calibration-based audio level indications, and integrates a microphone to mix ambient sound, allowing for customizable equalization and limiting output to prevent excessive exposure, while calibrating earphone sensitivity and frequency response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a volume limiter is used to protect hearing, then the maximum output level is reduced, but the protection is arbitrary and does not account for earphone sensitivity or exposure duration
Solution Approach 1:
The system continuously monitors the actual sound output through a microphone and provides real-time feedback to the processor, which then adjusts the volume limiter dynamically based on measured exposure levels, earphone sensitivity, and duration to provide accurate hearing protection
Solution Approach 2:
The patent replaces the simple mechanical volume limiter with an intelligent system that uses a microphone, processor, and software algorithms to measure and control sound exposure, substituting physical mechanical control with electronic sensing and computational adjustment
2Loss of information
If noise-isolating earphones are used to block ambient sound, then listening clarity is improved, but the user loses awareness of ambient sound levels
Solution Approach 1:
The system introduces a microphone as an intermediary that captures ambient sound and converts it into an electrical signal, which is then processed and mixed with the audio output to provide the user with awareness of ambient levels without compromising the noise-isolating benefit
3Adaptability or versatility
If earphone sensitivity varies, then different earphones produce different sound levels at the same output, but users lack calibration information to know actual exposure levels
Solution Approach 1:
The system performs preliminary calibration by measuring the sensitivity of each earphone before use through a standardized process involving playing test tones and measuring the output, storing this calibration data for later use in accurate sound level calculation
Solution Approach 2:
The system enables users to self-calibrate their own earphones using the provided calibration process, eliminating the need for manufacturer-provided sensitivity data and allowing users to accurately determine their own exposure levels
Data Source
AI summary
An audio processor device and method is disclosed which measures and provides information relating to the audio level being applied to the ear of a user. The processor device uses a preset or calibrated sensitivity of the applied earphones in combination with an analysis of the audio stream to provide sound-pressure-level or time-weighted exposure information to the user or limit the output when preset levels have been achieved. Also disclosed is the use of microphones, internal or external, to combine an additional audio stream, typically the ambient environment, into the main audio channel.