Speaker Directivity Control Using Microphone Delay Compensation
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Solution Overview
Problem
Conventional speaker systems fail to adjust directivity based on the listening position due to the absence of an exact measurement method for speaker driving, leading to inconsistent sound quality across different positions, and require special heat sink components which complicate installation.
Innovation Solution
A speaker system that uses multiple microphones to sense shock sounds at the listening position, measures signal delay values between channels, and applies compensation filter coefficients to input audio signals to control directivity, allowing for optimal sound reproduction by converting PCM signals to PWM and amplifying them using power switching units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If filters and amplifiers are integrated within each speaker unit, then power handling capability is improved, but heat management becomes difficult requiring special heat sink components
Solution Approach 1:
The patent extracts the amplifier from the speaker unit and places it in a separate location. The speaker unit contains only the speaker driver and associated components, while the amplifier is positioned remotely and connected via wiring. This separation removes the heat-generating amplifier from the speaker assembly, eliminating the need for heat sink components in the speaker unit while maintaining full power handling capability.
2Device complexity
If directivity is determined by physical construction and disposition of speaker units, then structural simplicity is maintained, but adaptability to different listening positions is lost
Solution Approach 1:
The patent introduces a movable or adjustable component that allows the speaker unit to change its orientation or directivity pattern dynamically. This could be an adjustable baffle, a rotatable speaker driver, or a movable reflector that redirects sound waves. The system transitions from a fixed physical construction to a dynamic configuration that can adapt to different listening positions without requiring complex multi-unit arrays.
3Power
If multiple speaker units are disposed in a linear array, then power handling is improved, but frequency quality becomes inconsistent across different listening positions
Solution Approach 1:
The patent incorporates feedback mechanisms that measure the acoustic output and adjust the system accordingly. This could involve microphones positioned at various locations that detect frequency imbalances, with the information fed back to the amplifier or speaker configuration to correct the distortion. The feedback loop continuously optimizes frequency quality across different listening positions, maintaining consistency even when multiple speaker units are used for high power handling.
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
Enables dynamic control of directivity based on the listening position, improving sound quality consistency and allowing for the installation of speakers and amplifiers together without heat-related complications.
Implementation Method 1
sensing in each channel a shock sound having an impulse pattern generated at a listening position
Implementation Method 2
a power switching unit amplifying the PWM audio signals converted by the controller and outputting the amplified PWM audio signals
Data Source
AI summary
A speaker system to control directivity of a speaker unit using a plurality of microphones, and a method thereof. The method includes sensing through a plurality of channels a shock sound with an impulse pattern generated at a listening position and measuring delay values between signals of the channels, reading a predetermined listening position compensation filter coefficient in accordance with the measured delay values, and controlling directivity of the speaker unit by granting the read compensation filter coefficient on input audio signals.