Passive Delay Network for Loudspeaker Beam Forming
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Solution Overview
Problem
Loudspeaker arrays struggle to create a consistent sound field due to inconsistencies in sound patterns generated by multiple drivers, which can be addressed by using digital delays or physical arrangements, but these solutions are often expensive and aesthetically unappealing.
Innovation Solution
A loudspeaker array with a delay network comprising multiple stages that introduce electrical delays to create a desired radiation pattern, allowing for an arc coverage pattern without the need for expensive digital time delay circuitry, using a ladder configuration of passive components like inductors and capacitors to simulate the effect of physical curving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital delay circuitry is used to create arc coverage pattern, then consistent sound field is achieved, but system cost increases
Solution Approach 1:
The patent replaces digital delay circuitry with an analog passive delay network composed of inductors and capacitors. This substitution eliminates the need for expensive digital processing while achieving the same acoustic delay effect through passive electrical components arranged in a ladder configuration.
Solution Approach 2:
The patent uses inexpensive passive components (inductors and capacitors) to replace costly digital delay circuitry. These passive components provide the necessary time delay function at a fraction of the cost of digital signal processing hardware, making the system more economically viable.
2Reliability
If physical curving of speaker array is implemented, then constant beam width is achieved, but aesthetic appeal and space efficiency deteriorate
Solution Approach 1:
Instead of physically curving the speaker array to achieve constant beam width, the patent inverts the approach by keeping the array straight and using passive delay networks to create the acoustic effect of curving. This allows the physical structure to remain simple and aesthetically pleasing while achieving the same acoustic performance.
Solution Approach 2:
The patent creates an acoustic copy of the curved array effect using passive delay networks. By introducing appropriate time delays to speakers along a straight array, the system reproduces the sound radiation pattern of a physically curved array without requiring the actual physical curvature.
3Measurement precision
If separate amp channel and digital time delay for each driver are provided, then precise beam forming is achieved, but system cost increases
Solution Approach 1:
The patent makes the passive delay network a universal solution that can be applied to multiple drivers simultaneously. Instead of requiring separate digital delay circuits for each driver, a single passive delay network topology can serve multiple speakers, reducing overall system complexity and cost while maintaining precise beam forming capability.
Solution Approach 2:
The patent combines the delay function with the speaker output stage by integrating passive delay networks directly at the speaker terminals. This merging of functions eliminates the need for separate delay circuits and amplifier channels, simplifying the system architecture while achieving precise temporal control for beam forming.
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 solution provides a cost-effective means to achieve a consistent sound field with a straight or flat speaker array, mimicking the performance of a curved array by adjusting delays and attenuation, resulting in a constant beam width and improved sound distribution across frequencies.
Implementation Method 1
A delay network is included, the delay network having a plurality of stages. Each stage has a stage input and a stage output. The stage output of each stage is coupled to the stage input of a next stage. Each stage output is also connected to at least one of the plurality of loudspeakers. The stage input of the first stage is coupled to an audio signal input. Each stage is configured to add an electrical delay of the audio signal at each subsequent stage.
Implementation Method 2
using a ladder configuration of passive components like inductors and capacitors to simulate the effect of physical curving
Data Source
AI summary
A loudspeaker array and methods for generating sound in an arc pattern. The loudspeaker array includes a plurality of loudspeakers. A delay network is included, the delay network having a plurality of stages. Each stage has a stage input and a stage output. The stage output of each stage is coupled to the stage input of a next stage. Each stage output is also connected to at least one of the plurality of loudspeakers. The stage input of the first stage is coupled to an audio signal input. Each stage is configured to add an electrical delay of the audio signal at each subsequent stage. The electrical delay is adjusted such that the plurality of loudspeakers generates sound in a desired radiation pattern.