Coaxial Centerbody Horn Speaker Directivity Control
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Solution Overview
Problem
Multi-driver horn loudspeakers face issues such as power response disparity between mid-range and high-frequency drivers, inefficient acoustic coupling, increased distortion, mechanical fatigue, wavefront interference, and loss of directivity at lower frequencies, which limit their effectiveness in professional applications.
Innovation Solution
The integration of mid-range drivers within the centerbody of the horn, allowing efficient acoustic coupling and phase-accurate summation with high-frequency drivers, reducing external footprint, and enabling directivity control across all frequencies through a novel annular acoustic lens horn profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If mid-range drivers are injected through outer horn wall apertures using band-pass chambers, then acoustic power can be introduced into the horn, but significant cancellation nulls occur at fundamental 1/2-wave frequencies limiting upper bandwidth
Solution Approach 1:
The patent extracts the mid-range driver injection point from the outer horn wall and relocates it to the inner surface of the horn, specifically at the centerbody termination. This removes the source of the cancellation nulls by eliminating the path that caused fundamental frequency cancellation, thereby extending the usable bandwidth without sacrificing acoustic power injection capability.
Solution Approach 2:
Instead of injecting sound from the exterior through band-pass chambers as in conventional designs, the patent inverts the approach by placing the injection point on the interior surface of the horn at the centerbody termination. This reversal eliminates the acoustic cancellation issues while maintaining effective power transfer to the horn air mass.
2Power
If band-pass aperture is used to inject mid-range acoustic power into horn air mass, then acoustic coupling is established, but large acoustic impedance discontinuity reduces coupling efficiency at higher frequencies
Solution Approach 1:
The patent removes the band-pass aperture chamber structure entirely and replaces it with direct injection through the centerbody termination into the horn air mass. This eliminates the acoustic impedance discontinuity that occurred at the band-pass aperture, improving coupling efficiency and enabling reliable operation across the full frequency range including high frequencies.
3Stress or pressure
If HF compression driver operates at high sound pressure levels to compensate for mid-range driver limitations, then sound pressure level is maintained, but air turbulence and non-linear heating increase producing acoustic distortion
Solution Approach 1:
The patent segments the frequency response by enabling the mid-range driver to operate efficiently up to high frequencies through direct injection at the centerbody termination. This eliminates the need for the HF compression driver to compensate for mid-range limitations, allowing each driver to operate in its optimal range and reducing overall distortion even at high sound pressure levels.
4Stability of the object's composition
If multiple drivers are integrated within single horn to improve wavefront coherence, then wavefront coherence is enhanced, but power response disparity remains between mid-range and high-frequency drivers
Solution Approach 1:
The patent extracts the mid-range driver injection point from the conventional outer wall location and positions it at the centerbody termination on the inner surface. This strategic repositioning ensures that mid-range and high-frequency drivers both inject acoustic power at the same location, eliminating power response disparity while maintaining the wavefront coherence benefits of integrated multi-driver design.
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 solution enables mid-range drivers to operate up to higher frequencies, reduces distortion and mechanical stress, improves wavefront coherence, and maintains uniform directivity across the frequency range, enhancing the loudspeaker's performance and reliability for professional applications.
Implementation Method 1
the annular acoustic channel forms into a unified flow
Implementation Method 2
controlled acoustic directivity at wavelengths larger than the nominal wavelength supported by the horns' mouth circumference
Data Source
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AI summary
The invention relates a horn-based multi-driver wide-bandwidth loudspeaker with a flat-frequency response having the property of controlled acoustic directivity at wavelengths larger than the nominal wavelength supported by the horns' mouth circumference which is provided by means of a centerbody fitted with acoustic drivers that are acoustically coupled to the walls of the horn enclosure.