Directional Speaker Cavity Layout for Far-Field Sound Leakage
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Solution Overview
Problem
Existing acoustic output devices face limitations in reducing sound leakage, particularly in far-field scenarios, despite using sound sources with opposite phases to cancel each other out.
Innovation Solution
The acoustic output device employs a housing with speakers that output sound waves through front and rear cavities, utilizing phase and amplitude differences to create directional sound pressure distributions, and a processing circuit to modulate electrical signals with filter functions, adjusting sound pressure distributions based on constraint functions to minimize sound leakage in specific directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If two sound sources with opposite phases are used to cancel each other out, then far-field sound leakage is reduced, but sound leakage in other directions may increase and the solution has limitations
Solution Approach 1:
The acoustic output device is divided into multiple independent speaker units (first speaker, second speaker, etc.), each capable of emitting sound waves with controlled phase and amplitude. This segmentation allows independent control of sound sources to achieve more sophisticated sound field manipulation and directional sound pressure distribution.
Solution Approach 2:
The patent implements different phase and amplitude characteristics for different sound sources and different frequency ranges. By applying local quality control, the device creates directional sound pressure distributions that are optimized for specific directions and frequency bands, rather than uniform sound cancellation in all directions.
Solution Approach 3:
The processing circuit dynamically adjusts the phase and amplitude of electrical signals provided to different speakers based on frequency range and directional requirements. This dynamic control enables the device to adaptively create optimal sound pressure distributions for different operating conditions and frequency bands.
2Object-generated harmful factors
If multiple speakers with different cavity configurations are used, then directional sound pressure distribution is achieved, but device complexity increases
Solution Approach 1:
The device uses multiple speakers with distinct cavity configurations (front cavities, rear cavities, acoustic couplings to different holes) to segment the sound emission paths. Each speaker-unit combination acts as an independent sound source with controllable directional characteristics, enabling precise sound pressure distribution control.
Solution Approach 2:
The processing circuit serves multiple functions: it generates electrical signals for multiple speakers, applies frequency-range-specific phase and amplitude adjustments, and coordinates the operation of different speaker-cavity systems to achieve directional sound pressure distribution across various frequency bands.
3Object-generated harmful factors
If phase and amplitude differences are applied to electrical signals for different speakers, then sound pressure distribution is controlled, but processing complexity increases
Solution Approach 1:
The processing circuit applies different phase and amplitude characteristics to electrical signals based on frequency ranges and target directions. This local quality approach allows optimized sound pressure distribution for specific frequency bands and directions without requiring complex processing for all frequencies uniformly.
Solution Approach 2:
The processing circuit dynamically adjusts signal parameters (phase and amplitude) for different speakers based on the frequency range of the audio signal. This dynamic adaptation enables effective sound leakage reduction across varying frequency conditions while maintaining manageable processing complexity through frequency-based signal separation.
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 device achieves flexible sound leakage reduction by creating targeted sound pressure distributions, effectively minimizing sound leakage in desired directions, enhancing user privacy and reducing interference with others.
Implementation Method 1
the first front cavity and the first rear cavity are acoustically coupled to two holes disposed on the housing, respectively to output a first sound wave and a second sound wave with a phase difference
Implementation Method 2
the first front cavity and the first rear cavity are acoustically coupled to two holes disposed on the housing, respectively
Implementation Method 3
The processing circuit is capable of obtaining a plurality of filter function groups, each of the plurality of filter function groups includes a first filter function and a second filter function corresponding to the first electrical signal and the second electrical signal, respectively. The first electrical signal and the second electrical signal are modulated in response to the first filter function and the second filter function, respectively.
Implementation Method 4
In a target frequency range, there is an amplitude difference and/or a phase difference between the first electrical signal and the second electrical signal to make a far-field radiated sound from the acoustic output device exhibit at least one directional sound pressure distribution.
Data Source
AI summary
The present disclosure relates to an acoustic output device including: a housing; a first speaker disposed in the housing and acoustically coupled to two holes disposed in the housing, respectively, to output a first sound wave and a second sound wave with a phase differences; a second speaker disposed in the housing and acoustically coupled to a hole provided on the housing to output a third sound wave; a processing circuit configured to provide a first electrical signal to the first speaker and provide a second electrical signal to the second speaker. There is an amplitude difference and/or a phase difference between the first electrical signal and the second electrical signal in a target frequency range to make a far-field radiated sound of the acoustic output device exhibit at least one directional sound pressure distribution.