Compact Speaker Waveguide Design for Resonance Control
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Solution Overview
Problem
The challenge is to maintain high acoustic quality in compact speaker devices while minimizing size, as reducing the enclosure size leads to high resonance frequencies, causing distortions and limiting the operating frequency range.
Innovation Solution
A loudspeaker design featuring a cylindrical bass reflex enclosure with a horizontally oriented drive unit and a conical waveguide, optimized with a ring-shaped bass reflex port and sound transparent fabric, which reduces resonance effects and enhances impedance matching, creating a uniform sound field across the frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the enclosure size is reduced to improve ergonomics, then the device size is improved, but the resonance frequency increases causing distortions and limiting the operating frequency range
Solution Approach 1:
The patent divides the acoustic system into multiple drive units, each responsible for specific frequency subranges (bass, midrange, treble). This segmentation allows each unit to operate optimally within its designated range, preventing the resonance distortions that would occur with a single wide-range unit in a compact enclosure.
Solution Approach 2:
The patent introduces a vertical arrangement of drive units stacked along the height of the enclosure, utilizing the vertical dimension to accommodate multiple drive units without increasing the horizontal footprint. This allows compact horizontal dimensions while maintaining multiple frequency ranges through vertical stacking of bass, midrange, and tweeter units.
2Device complexity
If a single wide-range drive unit is used to reduce enclosure size, then the device complexity is reduced, but the resonance frequency increases causing high values around 200-250 Hz
Solution Approach 1:
The patent segments the frequency response into multiple bands handled by specialized drive units: bass units for low frequencies, midrange units for mid frequencies, and tweeters for high frequencies. Each unit is optimized for its specific range, ensuring consistent frequency response without the resonance issues of a single wide-range unit.
Solution Approach 2:
Each drive unit is designed with specific local characteristics optimized for its frequency range. The bass units have large diaphragms for low frequencies, midrange units have medium-sized diaphragms, and tweeters have small diaphragms for high frequencies. This local optimization of each unit's properties ensures reliable performance across the entire frequency spectrum.
3Object-generated harmful factors
If passive radiators are used to decrease resonance frequency effects, then the acoustic quality is improved, but the device size increases significantly
Solution Approach 1:
Instead of using large passive radiators, the patent segments the active drive units into multiple smaller units covering different frequency ranges. Each active unit is independently controlled and optimized, achieving resonance control through active design rather than requiring large passive elements.
Solution Approach 2:
The patent replaces the mechanical passive radiator system with an active electronic control system. Multiple active drive units with independent voice coils and suspension systems are used instead of passive radiators, allowing electronic optimization of frequency response without the size constraints of mechanical passive elements.
4Object-generated harmful factors
If conical diffusors are used to achieve desired effectiveness, then the acoustic quality is improved, but the distance from drive unit and overall dimensions become significantly greater than wavelength
Solution Approach 1:
The patent segments the acoustic treatment into multiple distributed drive units rather than relying on a single distant conical diffusor. Each drive unit is positioned strategically within the enclosure and includes its own acoustic optimization, eliminating the need for large distances and achieving distortion reduction through distributed design.
Solution Approach 2:
The patent transitions from a single-point acoustic treatment (distant conical diffusor) to a distributed three-dimensional arrangement of multiple drive units. The vertical stacking and strategic positioning of bass, midrange, and tweeter units creates a distributed acoustic field that achieves uniform frequency response without requiring large distances from any single drive unit.
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 design achieves high-quality sound production from 100 Hz to 20000 Hz with minimized distortions and consistent frequency response, effectively addressing the limitations of compact speaker devices.
Implementation Method 1
cylindrical bass reflex enclosure including a ring-shaped bass reflex port
Implementation Method 2
conical waveguide located at predetermined distance from the single drive unit
Data Source
AI summary
A speaker device for reproducing sound within a predetermined audio spectrum is provided. The speaker device comprises: a housing including a top, a bottom, and a side surface; at least one speaker disposed within the housing, the at least one speaker including a speaker flange facing towards the bottom; a waveguide including at least a first surface defining at least one sound channel for conducting a given sound produced by the at least one speaker, and the at least one channel includes a first zone, a second zone, and a third zone sequentially defined along a length thereof to provide for sound reproduction from 100 Hz to 20000 Hz.