Headphone Acoustic Interference Structure for Sound Leakage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing headphones struggle with sound leakage, particularly at high frequencies, due to phase differences and acoustic path variations that prevent effective cancellation of sound signals from opposite phases.
Innovation Solution
The design incorporates a first and second acoustic wave generation structure with a phase difference of 120°-240°, an acoustic transmission structure, and a filtering structure to absorb specific frequency ranges, reducing sound leakage by interference and resonance absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If two acoustic sources of opposite phases are used to reduce sound leakage, then sound leakage is reduced to a certain extent, but high-frequency sound leakage cannot be effectively canceled due to non-negligible distance between sources compared to wavelength
Solution Approach 1:
The patent changes the phase difference parameter from the conventional 180° to a range of 120°-240°, and adjusts the distance between acoustic sources to be less than one-tenth of the shortest wavelength. This parameter optimization enables effective phase cancellation across both low and high frequency ranges, resolving the contradiction between reducing sound leakage and maintaining cancellation precision.
Solution Approach 2:
The patent introduces a dynamic adjustment mechanism that modifies the phase difference between acoustic sources based on frequency. By making the phase relationship adjustable rather than fixed, the system can adapt to different frequency characteristics, ensuring effective cancellation across the entire audio spectrum including high frequencies where fixed 180° phase difference fails.
2Power
If acoustic transmission structure resonates, then sound transmission is enhanced, but phase difference between radiated sound and original acoustic wave causes cancellation failure
Solution Approach 1:
The patent incorporates a feedback mechanism that monitors the acoustic transmission structure's resonance state and dynamically adjusts the phase difference between acoustic sources accordingly. This feedback control ensures that even when resonance occurs and causes phase shifts, the system can compensate by adjusting the source phase relationship, maintaining effective sound leakage cancellation while preserving sound transmission power.
3Object-affected harmful factors
If distance between two acoustic sources is increased to improve sound cancellation in far field, then far-field sound leakage is reduced, but high-frequency cancellation effectiveness decreases due to wavelength considerations
Solution Approach 1:
The patent optimizes the distance parameter by setting it to be less than one-tenth of the shortest wavelength, which is a significant departure from conventional designs. This parameter change, combined with adjusting the phase difference to 120°-240°, creates a configuration where both far-field and high-frequency cancellation requirements are satisfied simultaneously, eliminating the need to trade off between these two objectives.
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 approach effectively reduces sound leakage in both near and far fields by canceling sound waves in certain frequency ranges and absorbing others, enhancing user experience with improved sound quality.
Implementation Method 1
The first acoustic wave transmitted to the spatial point may interfere with the second acoustic wave transmitted to the spatial point in a first frequency range, and the interference may reduce an amplitude of the first acoustic wave in the first frequency range
Implementation Method 2
The filtering structure may be configured to absorb, in a target frequency range, the first acoustic wave transmitted through the acoustic transmission structure to reduce an amplitude of an acoustic wave generated by the headphone at the spatial point
Implementation Method 3
The acoustic transmission structure may be configured to transmit the first acoustic wave and the second acoustic wave to a spatial point outside the headphone
Data Source
AI summary
Embodiments of the present disclosure disclose a headphone including a first acoustic wave generation structure, a second acoustic wave generation structure, an acoustic transmission structure, and a filtering structure. The first acoustic wave generation structure and the second acoustic wave generation structure respectively generate a first acoustic wave and a second acoustic wave. The acoustic transmission structure may be configured to transmit the first acoustic wave and the second acoustic wave to a spatial point outside the headphone. The first acoustic wave transmitted to the spatial point interferes with the second acoustic wave transmitted to the spatial point in a first frequency range, and the interference reduces an amplitude of the first acoustic wave in the first frequency range. The filtering structure may be configured to reduce an amplitude of an acoustic wave generated by the headphone in a second frequency range at the spatial point.