Open Earphone Acoustic Layout for High-Frequency Leakage Control
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Solution Overview
Problem
Open acoustic output devices suffer from unsatisfactory far-field sound leakage reduction and interference due to varying sound wave phases at high frequencies, particularly in headphones with open designs.
Innovation Solution
A headphone design featuring a core housing with two speakers, each with distinct resonant frequencies, and separate sound outlets to output sounds of different frequency bands, ensuring a phase difference of at least 2000 Hz, thereby reducing sound leakage and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sound guide hole and pressure relief hole are used to cancel sound waves, then far-field sound leakage is reduced for low frequencies, but sound wave phase alignment fails at high frequencies causing interference and amplified leakage
Solution Approach 1:
The patent divides the sound output function into two independent channels: a first sound guide hole for low-frequency sound waves and a second sound guide hole for high-frequency sound waves. This segmentation allows each hole to be optimized for its specific frequency range, preventing phase alignment failures that occur when a single hole handles all frequencies. The separation ensures that low-frequency cancellation remains effective while high-frequency sound delivery is maintained without interference.
Solution Approach 2:
The patent applies different acoustic characteristics to different parts of the system by providing separate sound guide holes with different properties for different frequency ranges. The first sound guide hole is designed with characteristics suitable for low-frequency wave propagation, while the second sound guide hole is designed for high-frequency waves. This local quality differentiation ensures optimal performance for each frequency band without compromising the other.
2Ease of operation
If open acoustic output design is used, then comfort and breathability are improved, but sound leakage into surrounding environment increases
Solution Approach 1:
The patent segments the sound output into multiple frequency bands handled by separate sound guide holes, allowing the open design to maintain comfort while controlling sound leakage through frequency-specific acoustic pathways. The first sound guide hole handles low frequencies with cancellation capabilities, while the second handles high frequencies with directional control, together achieving comprehensive sound leakage management in an open design.
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 design effectively minimizes sound leakage and interference by utilizing speakers with specific frequency differences and separate sound outlets, enhancing auditory experience and stability.
Implementation Method 1
two sounds with opposite phases can be emitted from a sound guide hole in a front cavity and a pressure relief hole in a rear cavity of the acoustic output device. Under far-field conditions, an acoustic path difference between these two sounds with opposite phases reaching a certain point in the far field is essentially negligible. As a result, the two sounds can cancel each other out, reducing far-field sound leakage.
Implementation Method 2
The first front cavity includes a first resonant frequency, the first rear cavity includes a second resonant frequency, and the second speaker includes a third resonant frequency.
Data Source
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AI summary
The present disclosure relates to a headphone, and specifically relates to the technical field of electronic devices. A first speaker includes a first diaphragm. The first speaker cooperates with a core housing to form a first front cavity and a first rear cavity located at two sides of the first diaphragm. The core housing is provided with a first sound outlet for communicating with the first front cavity. The first front cavity includes a first resonant frequency. The first rear cavity includes a second resonant frequency. The second speaker includes a third resonant frequency. A difference between the third resonant frequency and the first resonant frequency and a difference between the third resonant frequency and the second resonant frequency are not less than 2000 Hz.