Confined-Space Audio Modulation for Low-Frequency Noise Cancellation
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Solution Overview
Problem
Existing sound-modulating devices fail to effectively address the issue of low-frequency noise and discomfort in confined spaces, such as elevators, and lack a practical solution to improve indoor sound quality in densely populated areas.
Innovation Solution
A sound-modulating device equipped with an event detector, audio module, low-frequency noise detector, and automatic actuator that plays music segments or generates audio signals to eliminate low-frequency noise and repel individuals, using frequencies ranging from 20 Hz to 20000 Hz and intensities up to 75 dB, and high-frequency repellent signals above 8000 Hz to create an uncomfortable environment for unwanted individuals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If no sound-modulating device is installed, then the confined space remains quiet and comfortable, but low-frequency noise cannot be eliminated and people cannot be repelled when needed
Solution Approach 1:
The sound-modulating device is designed to perform multiple functions: it can eliminate low-frequency noise using anti-phase sound waves, repel people using high-frequency sounds, and play music segments to relieve discomfort. This multi-functionality allows a single device to address various acoustic needs in confined spaces without requiring separate systems for each function.
Solution Approach 2:
The device changes the frequency and intensity parameters of emitted sounds based on the detected event type. For low-frequency noise elimination, it generates anti-phase waves at matching frequencies; for repelling people, it uses high-frequency sounds at intensities not greater than 60 dB; for comfort relief, it plays music segments with frequencies from 20 Hz to 20000 Hz and intensities up to 75 dB. This dynamic parameter adjustment resolves the contradiction by adapting the device's output to specific needs.
2Object-affected harmful factors
If high-frequency repellent audio signals are generated, then people can be repelled effectively, but the device complexity and energy consumption increase
Solution Approach 1:
The device uses an event detector to automatically detect when repelling is needed and triggers the audio module accordingly. The system serves itself by monitoring the environment and activating the high-frequency repellent signals only when the predetermined state is met, such as detecting a moving object within a specific region or when a timer detects a specific period of time has elapsed. This automatic activation based on detected events reduces unnecessary energy consumption compared to continuous operation.
Solution Approach 2:
The device employs periodic action through the timer component, which issues the second modulating signal if a specific period of time is met. This allows the repelling function to be activated at predetermined intervals or durations, reducing overall energy consumption while still achieving the repelling effect when needed.
3Object-affected harmful factors
If the audio module plays music segments continuously, then client comfort is improved, but energy consumption and device complexity increase
Solution Approach 1:
The event detector provides feedback about the presence of clients and the state of the confined space to the audio module. When the event detector detects that a client is present or that the door closing time exceeds a predetermined time period, it generates a trigger signal that activates the music segment playback. This feedback mechanism ensures the device only operates when needed, reducing complexity compared to continuous operation systems.
Solution Approach 2:
The device dynamically adjusts its operation based on real-time detection. The audio module plays music segments only when triggered by the event detector, and stops playing when the event ends. This dynamic on-demand operation reduces the need for complex continuous control mechanisms while still improving client comfort when needed.
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 device effectively reduces low-frequency noise through destructive interference and uses high-frequency signals to deter people, improving indoor sound quality and providing a comfortable environment in confined spaces by eliminating unwanted noise and occupants.
Implementation Method 1
The audio module generates a low-frequency audio signal for eliminating the low-frequency noise and generates a high-frequency repellent audio signal
Implementation Method 2
The first modulating signal generated by the low-frequency noise detector and the low-frequency noise have similar waveforms in antiphase
Implementation Method 3
The motion detector detects whether a client is present in the confined space
Data Source
AI summary
A sound-modulating device used in a confined space is provided. The sound-modulating device includes an event detector and an audio module in communication with each other. The event detector detects an event and generates a trigger signal in response to the detected event. The audio module plays a music segment in response to the trigger signal. The frequencies of the music segment range from 20 Hz to 20000 Hz. The intensities of the music segment are smaller than or equal to 75 dB.