Bulbous Waveguide Tip Loudspeaker for High Frequency Distortion
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Solution Overview
Problem
Existing loudspeaker systems face challenges in achieving balanced sound quality due to destructive interference in high-frequency performance, leading to irregularities in frequency response and sound coloration, particularly in bipolar speaker systems where the interaction between front and rear sound fields disturbs Sound Pressure Level measurements and listener preferences for spaciousness and clarity.
Innovation Solution
The implementation of a bipolar loudspeaker system with identical bulbous-tip waveguide transducers, where the rear sound power is reduced by about 6 dB relative to the front sound power, maintaining a flat tonal balance and using separate crossovers for front and rear arrays to optimize the spectral balance, ensuring a 2:1 sound power ratio and improved linearity, thereby enhancing localization and spaciousness while minimizing sound coloration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If rear firing loudspeakers are used to enhance reflected sound field for spaciousness, then spaciousness is improved, but sound coloration and reduced localization clarity occur due to excessive reflected sound
Solution Approach 1:
The patent employs asymmetric sound power distribution between front and rear transducers, with the rear transducer array producing reduced sound power (by approximately 6 dB) compared to the front array. This asymmetric configuration allows the system to maintain spaciousness through rear-firing reflections while preventing excessive reflected sound from causing coloration and localization issues.
2Illumination intensity
If bipolar loudspeaker configuration is used to balance direct and reflected sound, then spaciousness is improved, but speech clarity and sound colorization are reduced
Solution Approach 1:
The patent applies local quality by differentiating the acoustic characteristics of front and rear transducer arrays. The rear array is specifically designed with reduced sound power output to provide sufficient reflected sound for spaciousness while maintaining speech clarity and avoiding excessive reflections that would cause coloration. This localized adjustment optimizes different frequency and spatial components separately.
3Reliability
If conventional waveguide with tapered tip is used, then high frequency performance is improved, but destructive interference from central diaphragm section causes irregularities in frequency response
Solution Approach 1:
The patent segments the waveguide structure into distinct functional zones: a tapered section for general acoustic guidance and a bulbous tip section specifically designed to address destructive interference from the central diaphragm area. This segmentation allows each zone to perform its specific function - the tapered portion manages overall sound guidance while the bulbous tip compensates for central section interference patterns.
Solution Approach 2:
The bulbous tip acts as an intermediary acoustic element between the central diaphragm section and the external environment. It mediates the destructive interference by providing an extended acoustic path that allows the central section's sound waves to integrate more smoothly with peripheral section waves, reducing frequency response irregularities in the high frequency range.
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 configuration results in a more enjoyable sound quality with improved high-frequency performance, greater clarity, and a balanced sound field that retains the spatial effects of bipolar systems without harshness or loss of clarity, effectively addressing the limitations of prior art by ensuring the rear sound field does not overpower the direct sound.
Implementation Method 1
an electrodynamic acoustic transducer which includes a diaphragm, a voice coil, and a magnet
Data Source
AI summary
An electrodynamic acoustic transducer has a diaphragm and a frame with a pole piece carrying a bulbous waveguide tip which reduces or eliminates high frequency distortions caused by destructive interference within the transducer. The bulbous-tip structure clears the moving parts of the transducer and minimizes diffraction of sound energy, extending forward approximately to the plane defined by the outer periphery of the diaphragm when the diaphragm and voice coil are at rest. The bulbous-tip waveguide member extends radially outward above the central radiating area of the transducer diaphragm or cone so as to obscure the center portion of the diaphragm.