Multi-Driver Amplifier Output Circuit to Eliminate Circulating Currents
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Solution Overview
Problem
Passive multi-band loudspeaker systems suffer from inferior sound quality due to isolation of loudspeaker drivers from the amplifier's low output impedance feedback point, causing driver interaction and audible distortion, unlike bi-amped systems which provide cleaner sound but at the expense of additional amplifiers.
Innovation Solution
An amplifier circuit with separate output connectors for each driver, incorporating independent damping output inductors and optional components like common mode filters, ensuring direct control over each driver and minimizing circulating currents, effectively extending the bi-wiring principle to the feedback point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive multi-band loudspeaker systems use a single amplifier output for multiple drivers, then device complexity is reduced, but driver interaction causes circulating currents and audible distortion
Solution Approach 1:
The patent divides the single amplifier output into multiple separate output connectors (first output connector and second output connector), each independently connected to different loudspeaker drivers. This segmentation eliminates the shared impedance path that causes circulating currents, allowing each driver to be controlled independently without electrical interaction through the amplifier output.
2Object-generated harmful factors
If bi-amped systems are used to eliminate driver interaction, then sound quality improves, but device complexity and cost increase due to additional amplifiers
Solution Approach 1:
The patent segments the output stage to provide separate output connectors for different drivers, achieving the electrical isolation benefits of bi-amping without requiring separate amplifier channels. This allows a single amplifier to function effectively as multiple independent outputs.
Solution Approach 2:
The amplifier circuit is designed to provide multiple independent output connections from a single amplifier stage, making the amplifier serve multiple functions simultaneously - driving different drivers independently while maintaining low output impedance control over each connection.
3Reliability
If damping output inductors are used in passive systems, then driver protection is improved, but sound quality deteriorates due to isolation of the feedback point
Solution Approach 1:
The patent places separate damping output inductors in each output branch (first damping output inductor in the first output branch, second damping output inductor in the second output branch), allowing each driver to be protected independently while maintaining separate electrical paths that prevent circulating currents and preserve feedback point control.
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 configuration improves sound quality by eliminating circulating currents and ensuring the amplifier's feedback point directly controls each driver, achieving cleaner sound without the need for additional amplifiers, thus mimicking bi-amping without the added expense.
Implementation Method 1
The output stage is configured to provide a low output impedance at a controlled output and further configured to limit current flow to protect the loudspeaker driver from excessive power and back electromotive force (EMF)
Implementation Method 2
The amplifier circuit includes a feedback loop that feeds back a portion of the output signal to the input
Data Source
AI summary
An amplifier circuit is disclosed suitable for feeding a loudspeaker system having plural drivers. The amplifier circuit has an output stage and plural output connectors such that there is an output connector for each driver, wherein the output stage is connected separately to each output connector for independent connection to each driver. A method of feeding a loudspeaker system having plural drivers with an amplifier circuit having an output stage is also disclosed.