Loudspeaker Driver Nonlinear Control for Distortion and Bass Output
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Solution Overview
Problem
Conventional loudspeakers suffer from nonlinear audio distortion, which impairs sound quality and speech intelligibility, especially in smaller-sized systems where design constraints prioritize portability over sound quality.
Innovation Solution
A nonlinear control system for loudspeaker devices, including a vented box loudspeaker system and a passive radiator loudspeaker system, that uses a controller to determine target displacements and sound pressures based on input voltages and physical models, generating control voltages to control actual displacements and reduce distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional loudspeaker systems are designed to prioritize portability and compactness, then device size is reduced, but nonlinear audio distortion increases and sound quality deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the electrical parameters (voltage and current) supplied to the speaker driver based on real-time monitoring of driver displacement and acoustic output. The controller modifies these parameters to compensate for nonlinear distortion effects, effectively changing the operational parameters to maintain linear audio reproduction despite the compact physical constraints of the device.
2Power
If speaker driver displacement is increased to enhance bass output, then low frequency sound production is improved, but mechanical stress and overheating increase
Solution Approach 1:
The patent implements feedback control by continuously monitoring the actual displacement of the speaker driver using sensors and comparing it with the desired displacement trajectory. The controller uses this feedback information to adjust the electrical parameters in real-time, preventing excessive displacement that would lead to mechanical stress and overheating, while still allowing sufficient displacement for adequate bass output.
Solution Approach 2:
The system applies beforehand cushioning by predicting potential excessive displacement conditions through the physical model and compensating for them in advance. The controller uses the physical model of the loudspeaker system to anticipate when the speaker driver might exceed safe displacement limits and pre-adjusts the electrical parameters to prevent mechanical stress and overheating before they occur.
3Manufacturing precision
If electrical parameters are adjusted to compensate for nonlinear distortion, then sound quality is improved, but control system complexity increases
Solution Approach 1:
The patent replaces complex mechanical design modifications with an electronic control system. Instead of redesigning the physical structure of the loudspeaker to reduce distortion, the system uses electrical parameter adjustment through a controller to achieve the same goal. This substitution of mechanical solutions with electronic control reduces the need for complex physical modifications while maintaining improved sound quality.
4Measurement precision
If physical models are used to determine target displacement and control parameters, then distortion compensation accuracy is improved, but computational requirements increase
Solution Approach 1:
The system applies partial action by using a simplified physical model that captures the essential nonlinear behavior of the loudspeaker system without requiring complete mathematical accuracy. The controller uses this partial model to achieve sufficient distortion compensation for practical purposes, avoiding the excessive computational requirements that would result from more comprehensive models while still improving sound quality meaningfully.
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 nonlinear control system effectively compensates for nonlinear audio distortion, enhances bass output, and provides mechanical protection by preventing excessive displacements and overheating, resulting in improved sound quality and reduced distortion.
Implementation Method 1
A nonlinear control system for loudspeaker devices, including a vented box loudspeaker system and a passive radiator loudspeaker system, that uses a controller to determine target displacements and sound pressures based on input voltages and physical models, generating control voltages to control actual displacements
Data Source
Figure 1~2A
Figure 2B~3A
Figure 3B
AI summary
One embodiment provides a vented box loudspeaker system comprising a speaker driver and a controller configured to receive a source signal for reproduction via the driver, determine a target displacement of the driver and a target sound pressure based on a first physical model of the system, and generate a control voltage based on the target displacement, the target sound pressure, and a second physical model of the system. Another embodiment provides a passive radiator loudspeaker system comprising an active speaker driver and a controller configured to receive a source signal for reproduction via the driver, determine a target displacement of a component based on a first physical model of the system, and generate a control voltage based on the target displacement and a second physical model of the system. In both embodiments, an actual displacement of the driver during the reproduction is controlled based on the generated control voltage.