Bone and Air Conduction Audio Timing for Stereo Synchronization
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Solution Overview
Problem
Existing acoustic devices using both bone conduction and air conduction methods suffer from sound deviation due to asynchronous emission of sound waves, leading to an unsatisfactory user experience, particularly in the mid-frequency range where the intensity of both sound types is comparable.
Innovation Solution
The acoustic device employs a signal processing method that delays the transmission of one of the driving signals relative to the other to ensure a time difference of less than or equal to 100 microseconds between the generation of bone conduction and air conduction sound waves, particularly in the mid-frequency band, thereby synchronizing the sound output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bone conduction and air conduction sound waves are emitted simultaneously without delay adjustment, then the device structure is simple and operation is easy, but sound deviation occurs due to asynchronous emission leading to unsatisfactory user experience
Solution Approach 1:
The signal processing circuit performs preliminary delay adjustment on one of the driving signals before emission to compensate for the inherent time delay difference between bone conduction and air conduction sound waves. This preliminary action ensures that both sound waves arrive at the user's ear simultaneously, eliminating sound deviation while maintaining a relatively simple device structure.
2Reliability
If delay processing is applied to synchronize bone conduction and air conduction sound waves, then sound deviation is avoided, but the signal processing complexity increases
Solution Approach 1:
The signal processing circuit automatically performs delay adjustment based on pre-calibrated parameters specific to each sound transmission path. The system self-regulates the timing without requiring manual intervention or complex user operations, achieving sound synchronization while keeping the operation simple and intuitive for users.
3Adaptability or versatility
If bone conduction sound component is used for mid-high frequencies and air conduction for mid-low frequencies, then frequency coverage is improved, but asynchronous emission causes sound deviation in mid-frequency range where both intensities are comparable
Solution Approach 1:
The signal processing circuit applies different delay adjustments specifically tailored to each frequency component and transmission path. By treating the mid-frequency range (where both bone conduction and air conduction intensities are comparable) with special delay compensation, the system maintains sound synchronization in the critical mid-frequency range while preserving the expanded frequency coverage benefits.
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 synchronization effectively avoids sound deviation, providing a better listening experience by ensuring synchronized sound waves across various frequency ranges, including mid-low and mid-high frequencies, and reduces overall power consumption.
Implementation Method 1
a bone conduction sound component, configured to generate a first time delay when converting a first driving signal into a bone conduction sound wave
Implementation Method 2
an air conduction sound component, configured to generate a second time delay when converting a second driving signal into an air conduction sound wave
Implementation Method 3
one of the first driving signal and the second driving signal is delayed relative to the other, so that at least at partial frequencies the bone conduction sound wave is generated at a first time, the air conduction sound wave is generated at a second time, and a time difference between the first time and the second time is less than or equal to 100 microseconds
Data Source
AI summary
To provide an acoustic output device which utilizes a combination of an air-transmitted sound with a bone-transmitted sound produced through bone transmission, and therefore can reproduce a more natural and realistic stereophonic sound regardless of the shapes of ears, the differences among individuals or the faultiness in a recording system or a regeneration system. [Solution] An acoustic output device is provided, which is equipped with an air-transmitted sound display unit for displaying an air-transmitted sound and a bone-transmitted sound display unit for displaying a bone-transmitted sound, wherein the bone-transmitted sound display unit is located at a position which is not in the vicinity of an ear of a user when the user puts on the acoustic output device. According to the acoustic output device, a stereophonic sound can be regenerated regardless of the shapes of ears, the differences among individuals or the faultiness in a recording system or a regeneration system.