Localized Speaker Pair Layout Using Opposite-Phase Sound
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Solution Overview
Problem
Conventional earphones or headphones for listening to audio in aircraft cause discomfort and are cumbersome, and synthesizing a virtual sound field with a large-scale speaker array is not practical.
Innovation Solution
A speaker system using at least two sets of speakers, each comprising a first speaker emitting an acoustic signal and a second speaker emitting an opposite phase signal, to create a sound field audible only in the vicinity of the speakers and not to surrounding users.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a speaker is used for sound reproduction, then the user can listen to audio without wearing earphones or headphones, but the reproduced sound reaches the periphery and causes disturbance to other users
Solution Approach 1:
The speaker system is divided into multiple independent speaker units (first speaker and second speaker) that can be controlled separately. Each speaker unit emits sound waves that can be individually phased to create directional sound patterns, allowing the sound to be confined to a specific region in front of the user without disturbing surrounding areas.
Solution Approach 2:
The patent creates a localized sound field with specific acoustic properties in front of the user by controlling the phase and amplitude of each speaker unit. The sound energy is concentrated in a narrow angular range (approximately ±30 degrees) directly in front of the speakers, while sound propagation to the sides and rear is minimized through destructive interference patterns.
2Object-generated harmful factors
If a large-scale speaker array is used to synthesize a virtual sound field, then the sound can be directed to the user, but the system complexity and cost increase significantly
Solution Approach 1:
Instead of using a complete large-scale speaker array for full 360-degree sound field synthesis, the patent employs a simplified configuration with only two speaker units. This partial implementation is sufficient to create the necessary directional sound pattern in the critical forward direction, achieving the primary goal without the complexity of a full array system.
Solution Approach 2:
The patent achieves sound directionality by changing the phase parameter of the acoustic signals emitted by each speaker unit. By setting the second speaker to emit sound in opposite phase to the first speaker, destructive interference is created in directions other than directly in front, while constructive interference occurs in the forward direction, creating a directional sound beam without requiring complex physical structures.
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 system reproduces sound that can be heard only in a very limited narrow range, eliminating the need for earphones or headphones and reducing disturbance to others.
Implementation Method 1
a first speaker that emits an acoustic signal, and a second speaker that emits the acoustic signal in a phase opposite to the first speaker
Implementation Method 2
emits an acoustic signal that is audible to a user in the vicinity of a speaker and not audible to a user outside the vicinity of the speaker
Data Source
AI summary
A sound that cannot be heard by surrounding users is reproduced. A reproduction device (110) includes an n-th reproduction unit that outputs a 2n−1th acoustic signal (n=1, . . . , N) that is an acoustic signal obtained on the basis of a reproduction target and a 2n-th acoustic signal that is an acoustic signal having a phase opposite to that of the 2n−1th acoustic signal. A speaker system (120) includes at least two or more sets of an n-th speaker unit pair (122) including a positive speaker unit (1221) that emits a 2n−1th acoustic signal-based sound and a negative speaker unit (1222) that emits a 2n-th acoustic signal-based sound, the n-th speaker unit pair being installed at a position close to a user's head.