Open Audio Device Acoustic Cavity Resonance Matching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Open audio devices experience increased sound spillage due to unbalanced front and rear acoustic resonance frequencies, leading to higher sound radiations at frequencies above the resonant frequencies, which detracts from their usefulness and desirability.
Innovation Solution
The design of an open audio device with acoustically coupled front and rear acoustic cavities, where the fundamental resonance frequencies are matched by adjusting the volumes and lengths of the cavities and their respective openings, and incorporating resistive elements to dampen resonances and direct sound effectively, thereby reducing sound spillage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If open audio devices are used to allow environmental awareness and social interaction, then user awareness and social cues are improved, but sound spillage increases and can be heard by others
Solution Approach 1:
The patent applies parameter changes by adjusting the resonance frequencies of the front and rear acoustic cavities to be equal. This is achieved by modifying the volumes and lengths of the cavities and their openings, which changes the acoustic parameters to minimize sound spillage while maintaining open audio device functionality.
Solution Approach 2:
The patent uses resistive elements (such as resistive screens or porous materials) in the acoustic cavities and transmission lines. These composite acoustic structures help dampen resonances and control sound radiation, reducing spillage while allowing the device to remain open.
2Ease of operation
If the acoustic transducer is spaced from the ear in open audio devices, then environmental awareness is improved, but sound spillage increases compared to on-ear headphones
Solution Approach 1:
The patent changes the acoustic parameters by equalizing the resonance frequencies of front and rear cavities. This parameter adjustment allows the acoustic transducer to be spaced from the ear while minimizing sound spillage through controlled acoustic resonance matching.
Solution Approach 2:
The patent introduces resistive elements as intermediary components within the acoustic cavities and transmission lines. These intermediaries dampen the acoustic resonances and control sound radiation, reducing spillage without requiring the transducer to be in direct contact with the ear.
3Device complexity
If the resonance frequencies of front and rear acoustic cavities are unbalanced, then device simplicity is maintained, but sound spillage increases at frequencies above resonance
Solution Approach 1:
The patent resolves the contradiction by changing the acoustic parameters of the cavities - specifically adjusting volumes and lengths to achieve equal resonance frequencies. This parameter optimization reduces sound spillage while maintaining a relatively simple overall device structure.
Solution Approach 2:
The patent applies dynamic principles by using resistive elements that can be adjusted or configured to dampen resonances. This allows the acoustic system to dynamically control sound radiation characteristics, reducing spillage at frequencies above resonance while maintaining structural simplicity.
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 minimizes sound spillage by ensuring that the front and rear acoustic resonance frequencies are nearly equal, maintaining low spillage up to the resonance frequencies while ensuring appropriate sound delivery to the ear, thereby enhancing user experience and device desirability.
Implementation Method 1
an acoustic radiator that emits front-side acoustic radiation from a front side of the acoustic radiator and emits rear-side acoustic radiation from a rear side of the acoustic radiator
Implementation Method 2
incorporating resistive elements to dampen resonances and direct sound effectively
Implementation Method 3
the fundamental resonance frequencies are matched by adjusting the volumes and lengths of the cavities and their respective openings
Data Source
AI summary
An open audio device that includes an acoustic radiator that emits front-side acoustic radiation from its front side and emits rear-side acoustic radiation from its rear side, a front acoustic cavity that receives front-side acoustic radiation, a front transmission line that is acoustically coupled to the front acoustic cavity and comprises a first front sound-emitting opening, and a rear acoustic cavity that receives rear-side acoustic radiation and comprises at least a first rear sound-emitting opening.