Portable Speaker Passive Diaphragm and Acoustic Absorption
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Solution Overview
Problem
Portable device speakers face challenges in maintaining audio performance due to limited space, which restricts bass response and overall sound quality.
Innovation Solution
The implementation of a speaker design that includes a separate passive diaphragm tuned to resonate with the active speaker at low frequencies, combined with the use of small sound absorbing particles in the back volume to increase the virtual back volume, enhancing bass output without increasing physical size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the physical size of the speaker is increased to improve bass response, then bass performance is improved, but the device size increases which is not acceptable for portable devices
Solution Approach 1:
The patent changes the physical parameters of the back volume cavity by introducing sound absorbing material, which modifies the acoustic properties without changing the physical dimensions. This allows the same physical space to provide enhanced bass response equivalent to a larger volume
Solution Approach 2:
Sound absorbing material is introduced as an intermediary substance within the back volume cavity. This material mediates between the limited physical space and the required acoustic volume, creating a 'virtual' larger back volume that improves bass performance without increasing device size
2Reliability
If sound absorbing material is added to increase virtual back volume, then bass response is improved, but the available space within the device is reduced
Solution Approach 1:
The patent utilizes porous sound absorbing material that can be packed into the existing back volume cavity. The porous structure allows the material to absorb acoustic energy while occupying minimal physical space, effectively increasing the acoustic volume without significantly reducing the available space for other components
3Reliability
If the back volume is enlarged to improve low frequency output, then bass output is enhanced, but the speaker thickness increases which conflicts with thin form factor requirements
Solution Approach 1:
The patent changes the acoustic parameters of the existing back volume by adding sound absorbing material, transforming the physical space into an acoustically larger volume. This allows enhanced low frequency output without increasing the speaker thickness, maintaining the thin form factor requirement
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 effectively boosts bass performance in portable device speakers, improving sound pressure levels at low frequencies while maintaining a compact form factor, thus enhancing user experience without compromising battery life or antenna efficiency.
Implementation Method 1
a separate passive diaphragm tuned to resonate with the active speaker at low frequencies
Implementation Method 2
the use of small sound absorbing particles in the back volume to increase the virtual back volume
Data Source
AI summary
Methods and apparatus to improve bass response of speakers in portable devices are disclosed. An example speaker includes a speaker box having a front face and a back face, a distance between the front face and the back face being less than 1 inch. The speaker box has a first portion of a back volume and a second portion of the back volume, the first portion of the back volume defined between the back face and a first region of the front face, the second portion of the back volume defined between the back face a second region of the front face. The example speaker further includes an active speaker driver including a first diaphragm, the first diaphragm coupled to the first region of the front face. The example speaker also includes a second diaphragm coupled to the second region of the front face, the second diaphragm being passive.