Bone Conduction Speaker Sound Leakage Reduction via Acoustic Interference
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Solution Overview
Problem
Bone conduction speakers experience sound leakage due to vibrations causing air displacement, which can compromise privacy and disturb others, and existing solutions like dual magnetic structures increase weight and cost without satisfactory sealing.
Innovation Solution
Incorporating sound guiding holes in the housing of the bone conduction speaker to guide sound waves inside the device outwards, where they interfere with leaked sound waves, reducing their amplitude and minimizing sound leakage without increasing the device's volume or weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If sound guiding holes are added to guide sound waves outwards for interference, then sound leakage is reduced, but device structure becomes more complex
Solution Approach 1:
The housing is segmented by incorporating sound guiding holes that create separate sound transmission paths. These holes divide the internal sound field into multiple paths that can be controlled independently, allowing sound waves to be guided outwards in specific directions to create interference patterns that reduce sound leakage.
Solution Approach 2:
The sound guiding holes act as intermediary structures that mediate between the internal sound field and the external environment. By controlling the phase and amplitude of sound waves passing through these holes, the system creates destructive interference with leaked sound waves, thereby reducing sound leakage without requiring complete sealing.
2Object-generated harmful factors
If dual magnetic structure is used to reduce sound leakage, then sealing is improved, but weight and cost increase
Solution Approach 1:
The invention extracts the sound leakage control function from the magnetic structure and relocates it to the housing design through sound guiding holes. This separates the sealing function from the magnetic components, allowing weight reduction while maintaining sound leakage control through acoustic interference mechanisms.
Solution Approach 2:
The mechanical sealing approach of dual magnetic structures is replaced with an acoustic interference approach using sound guiding holes. Instead of physically blocking sound leakage through additional magnetic components, the system uses phase-controlled sound wave interference to achieve the same effect with lighter housing materials.
3Object-generated harmful factors
If dual magnetic structure is used to reduce sound leakage, then sealing is improved, but manufacturing cost increases
Solution Approach 1:
The sound guiding holes are integrated directly into the housing structure, merging the sound leakage control function with the existing housing manufacturing process. This eliminates the need for separate dual magnetic structures and their associated assembly steps, reducing manufacturing complexity and cost while achieving effective sound leakage reduction.
4Reliability
If housing is made to vibrate synchronically with transducer, then sound transmission is improved, but sound leakage increases
Solution Approach 1:
The housing is designed with differentiated local qualities: certain portions are configured to vibrate synchronically with the transducer for effective sound transmission to the user, while other portions incorporate sound guiding holes that control and direct sound wave paths to create destructive interference with leaked sound waves. This local differentiation allows simultaneous optimization of both sound transmission and sound leakage control.
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 solution effectively reduces sound leakage by up to 20 dB in specific frequency ranges, maintaining the speaker's reliability and cost-effectiveness while improving user privacy and reducing disturbance.
Implementation Method 1
the air inside the housing is pushed out of the housing through the at least one sound guiding hole, interferes with the leaked sound wave, and reduces an amplitude of the leaked sound wave
Data Source
AI summary
A speaker comprises a housing, a transducer residing inside the housing, and at least one sound guiding hole located on the housing. The transducer generates vibrations. The vibrations produce a sound wave inside the housing and cause a leaked sound wave spreading outside the housing from a portion of the housing. The at least one sound guiding hole guides the sound wave inside the housing through the at least one sound guiding hole to an outside of the housing. The guided sound wave interferes with the leaked sound wave in a target region. The interference at a specific frequency relates to a distance between the at least one sound guiding hole and the portion of the housing.