Exponentially Spaced Loudspeaker Array for Directional Sound
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Solution Overview
Problem
Existing directional sound transmission technologies, such as reflector-based and horn loudspeakers, face limitations in low-frequency response and require high intensity, which can be unsafe for human listeners, while line arrays with uniform spacing do not achieve optimal directionality across a wide band of frequencies.
Innovation Solution
A system utilizing a line array of directional loudspeakers with exponentially increasing spacing, where each loudspeaker receives a driving signal with an exponentially increasing time-delay, allowing for constructive interference in the desired direction and destructive interference elsewhere, enhancing directionality across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If reflector-based directional speakers are used, then sound directionality is improved, but low frequency response deteriorates due to reflector diameter limitations
Solution Approach 1:
The system divides a single loudspeaker source into multiple loudspeakers arranged in a linear array. By segmenting the sound source and coordinating their operation with specific time delays, the system achieves directional sound transmission without relying on a physical reflector, thereby maintaining low frequency response capability.
Solution Approach 2:
The invention replaces the mechanical reflector structure with an electronic control system that uses time-delayed signal processing. Instead of physically reflecting sound waves using a large diameter reflector, the system electronically controls the phase and timing of multiple loudspeakers to achieve the same directional effect, eliminating the low frequency limitation imposed by reflector size.
2Shape
If horn loudspeakers with large dimensions are used, then sound directionality is improved, but device size increases
Solution Approach 1:
The system replaces a single large horn loudspeaker with multiple smaller loudspeakers arranged in a linear array. By segmenting the sound source and using electronic time-delay control, the system achieves comparable or superior directionality without requiring large physical dimensions, thereby reducing overall device size.
Solution Approach 2:
The invention replaces the mechanical horn structure with an electronic time-delay system. Instead of relying on the physical geometry of large horn dimensions to achieve directionality, the system uses electronic signal processing to control the phase and timing of multiple loudspeakers, achieving the same effect with much smaller physical dimensions.
3Shape
If parametric arrays with high intensity ultrasonic carriers are used, then sound directionality is improved, but safety for human listeners deteriorates due to high intensity requirements
Solution Approach 1:
The system replaces the use of high intensity ultrasonic carriers with audible frequency loudspeakers operating at safe intensity levels. By using multiple audible loudspeakers with electronic time-delay control, the system achieves directional sound transmission without requiring the potentially harmful high intensity levels needed by parametric arrays.
Solution Approach 2:
The invention replaces the ultrasonic parametric array mechanism with audible frequency loudspeakers and electronic time-delay processing. Instead of relying on nonlinear acoustic effects at high ultrasonic intensities, the system uses linear acoustic superposition with controlled phase relationships, achieving directionality at safe audible intensity levels.
4Ease of manufacture
If line arrays with uniform spacing are used, then ease of manufacture is improved, but directionality across wide frequency range deteriorates
Solution Approach 1:
The system uses non-uniform spacing between loudspeakers in the linear array, with spacing that increases exponentially from one end to the other. This asymmetric spacing configuration optimizes the array's directional performance across a wide frequency range by ensuring that different frequency components are properly directed, overcoming the limitations of uniform spacing.
Solution Approach 2:
The invention changes the spacing parameter between adjacent loudspeakers from a constant value to an exponentially increasing value. This parameter change optimizes the array's performance across wide frequency ranges by ensuring that the spacing between elements is appropriate for different wavelengths, improving directionality for both low and high frequency sounds simultaneously.
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 focuses sound in any direction, improving low-frequency response and reducing the need for high intensity, enabling precise sound delivery for applications like theme park rides and performance areas without disturbing adjacent scenes.
Implementation Method 1
allowing for constructive interference in the desired direction and destructive interference elsewhere
Data Source
AI summary
A system and method for the directional transmission of sound is disclosed. In one embodiment, the system comprises an audio source configured to generate an audio signal, a control module configured to receive the audio signal and generate a driving signal, based at least in part on the audio signal, and an array comprising a plurality of loudspeakers, wherein the loudspeakers are linearly arranged such that the spacing between two adjacent loudspeakers increases along the array. In a particularly, embodiment, the spacing increases exponentially, and broadband dipole loudspeakers are used.