Partition Speaker Layout Using Helmholtz Resonance to Reduce Sound Leakage
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Solution Overview
Problem
Existing sound emitting devices suffer from significant sound leakage, particularly in low-frequency components, due to diffraction in directions other than the target direction, which compromises privacy and sound quality in semi-private settings.
Innovation Solution
A sound emitting apparatus with a speaker unit and an enclosure forming a Helmholtz resonator, where the resonance frequency is set equal to or higher than the reproducible lower limit frequency of the speaker, combined with a partition that acts as an acoustic blocker, effectively reducing sound leakage by canceling diffracted sounds through opposite phase output from a port.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional speaker is used without a Helmholtz resonator, then the structure is simple, but sound leakage occurs due to diffraction of low-frequency sound components in directions other than the target direction
Solution Approach 1:
A Helmholtz resonator is introduced as an intermediary acoustic element between the speaker and the environment. The resonator couples to the speaker's acoustic output and selectively attenuates diffracted low-frequency sound components through its resonance characteristics, reducing sound leakage without requiring complex active control systems or additional shielding structures.
Solution Approach 2:
The acoustic parameters of the speaker system are modified by adding the Helmholtz resonator, which changes the frequency response and directional characteristics of the system. The resonator's natural frequency is tuned to match the diffracted low-frequency components, transforming the speaker's acoustic field distribution to reduce leakage in non-target directions.
2Object-affected harmful factors
If the resonance frequency of the Helmholtz resonator is set below the reproducible lower limit frequency of the speaker unit, then low-frequency sound reinforcement is achieved, but sound leakage increases due to diffraction of low-frequency components
Solution Approach 1:
The critical parameter change is setting the Helmholtz resonator's resonance frequency Fr to be equal to or higher than the speaker unit's reproducible lower limit frequency Fmin. This parameter relationship Fr≥Fmin ensures that the resonator attenuates diffracted low-frequency components that would otherwise leak, while preserving the speaker's useful low-frequency output capability. The resonator selectively targets only the problematic diffracted components above Fmin for attenuation.
3Object-affected harmful factors
If a bass reflex port is used as a Helmholtz resonator, then low-frequency sound reinforcement is achieved, but sound leakage occurs because the resonator is designed to reinforce rather than suppress diffracted sound components
Solution Approach 1:
Instead of designing the Helmholtz resonator to reinforce low-frequency sound components (conventional bass reflex approach), the invention inverts the objective by designing the resonator to suppress and attenuate diffracted low-frequency components. The resonator is positioned and tuned so that its anti-phase acoustic output cancels the diffracted sound waves in non-target directions, transforming the resonator's role from sound reinforcement to sound leakage suppression.
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
Significantly reduces sound leakage from semi-private spaces, ensuring that only intended listeners can hear the sound while minimizing noise pollution for others, thereby enhancing privacy and sound quality.
Implementation Method 1
an enclosure of the speaker unit having an aperture configuring a Helmholtz resonator
Implementation Method 2
a low-frequency sound component that is easily diffracted in a direction other than a target direction
Data Source
AI summary
A partition system with a speaker includes a plurality of wall surfaces configuring an acoustic blocker that is partially open and partially blocked, in a plan view, and having a first wall surface and a second wall surface, and a directional speaker disposed on the first wall surface and having a sound emitting direction to the acoustic blocker. The directional speaker includes a speaker unit, an enclosure of the speaker unit, and an aperture configuring a Helmholtz resonator, wherein a resonance frequency Fr of a Helmholtz resonator is set to be equal to or higher than a reproducible lower limit frequency F min of the speaker unit.