Loudspeaker Array Cabinet With Acoustic Lens Waveguide
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Solution Overview
Problem
Conventional guitar and bass guitar sound reinforcement systems with multiple cone drivers, such as a 4×12″ driver arrangement, are inadequate for signal chain modeling and live sound reinforcement due to directivity and frequency response deficiencies.
Innovation Solution
A loudspeaker system with a woofer section and a controlled-directivity horn section, featuring a waveguide and acoustic lens, is configured to provide a full-range response from 20 Hz to 20,000 Hz, ensuring coherent acoustic output and constant dispersion across horizontal and vertical planes, suitable for live sound applications and integration with professional amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional cone drivers (4×12″ arrangement) are used in guitar and bass guitar sound reinforcement systems, then the system structure is simple and easy to manufacture, but the directivity control and frequency response are inadequate
Solution Approach 1:
The loudspeaker system is segmented into distinct frequency ranges with dedicated drivers: subwoofer (20-200 Hz), woofer (200-2000 Hz), and mid-range horn (2000-20000 Hz). Each segment handles specific frequency bands, allowing optimized performance for each range while maintaining overall system coherence through controlled directivity.
Solution Approach 2:
An acoustic lens is introduced as an intermediary component between the mid-range loudspeaker driver and the waveguide. This acoustic lens shapes and directs the sound waves, enabling precise control over the dispersion pattern and frequency response in the mid-range section, thereby resolving the directivity control deficiency.
2Device complexity
If multiple cone drivers are stacked in conventional arrangements, then the system is easy to construct, but the acoustic output coherence and polar response are insufficient
Solution Approach 1:
The system divides acoustic output into coherent segments by frequency and direction. The subwoofer and woofer sections provide omnidirectional low-frequency output, while the mid-range horn section with acoustic lens provides controlled directional output. This segmentation ensures that each frequency range contributes coherently to the overall acoustic field without interference.
Solution Approach 2:
The system changes the directivity parameter across different frequency ranges. Low-frequency drivers operate with wide, omnidirectional dispersion, while the mid-range section transitions to controlled-directivity mode using the acoustic lens and waveguide. This parameter change optimizes acoustic coherence for each frequency band's characteristics.
3Use of energy by moving object
If conventional loudspeaker systems are used, then the system can be powered by simple amplifiers, but the system cannot provide sufficient acoustical power projection and suitable polar response
Solution Approach 1:
The system segments power distribution across three frequency sections, each optimized for its range. The subwoofer and woofer sections handle high-power low-frequency content with omnidirectional radiation, while the mid-range horn section handles high-frequency content with controlled directivity. This segmentation allows efficient power utilization and projection across the full frequency spectrum.
Solution Approach 2:
The system adds the dimension of controlled directivity to the traditional omnidirectional loudspeaker approach. The mid-range horn section with acoustic lens introduces directional control in the horizontal and vertical planes, creating a three-dimensional sound field structure that enhances power projection while maintaining coherence across different listening positions.
4Adaptability or versatility
If conventional cabinet designs are used, then the system is simple to integrate with existing equipment, but the system cannot reproduce instrument sounds without additional coloration
Solution Approach 1:
The system segments the frequency response into three distinct sections with carefully designed crossover points. The subwoofer (20-200 Hz), woofer (200-2000 Hz), and mid-range horn (2000-20000 Hz) sections are designed to blend seamlessly, reproducing the full frequency spectrum without coloration. Each section's frequency response and directivity are optimized to maintain signal fidelity.
Solution Approach 2:
The system changes the impedance and sensitivity parameters across different frequency sections to match optimal amplifier loading conditions. The subwoofer and woofer sections present appropriate impedance characteristics for high-power amplification, while the mid-range horn section is optimized for high-frequency response. These parameter changes enable accurate signal reproduction while maintaining compatibility with professional audio equipment.
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
The system delivers lower distortion, wider acoustic bandwidth, precise dispersion control, and faithful reproduction of instrument signals without additional coloration, making it suitable for live performances and signal chain modelers.
Implementation Method 1
an acoustic lens having a first side and an opposite second side, wherein the first side of the lens is coupled to a sound-projecting face of the second loudspeaker driver
Implementation Method 2
a waveguide coupled to the second side of the lens, wherein the waveguide comprises walls that follow arcuate paths in horizontal and vertical planes
Implementation Method 3
a controlled-directivity (or substantially constant-directivity) horn section configured to reproduce other audio signals in a different second frequency range
Data Source
AI summary
A substantially full-range loudspeaker system for acoustic sound reinforcement can include a woofer section with a first loudspeaker driver configured to reproduce audio signals in a first frequency range and a controlled-directivity horn section configured to reproduce other audio signals in a different second frequency range. In an example, the horn section includes a second loudspeaker driver comprising a cone-diaphragm transducer and a dust dome, an acoustic lens having a first side and an opposite second side, wherein the first side of the lens is coupled to a sound-projecting face of the second loudspeaker driver, and a waveguide coupled to the second side of the lens, wherein the waveguide comprises walls that follow arcuate paths in horizontal and vertical planes.