Ceiling Reflection Speaker Audio Processing Time Lag Compensation
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Solution Overview
Problem
Ceiling reflection type speakers cause a time lag difference between low and high frequency audio, leading to a loss of sense of localization and connection with other audio channels due to differing arrival routes.
Innovation Solution
An audio processing device delays the low frequency component and extracts the high frequency component using high-pass filtering, then combines and outputs them as an analog signal to the ceiling reflection type speaker, calculating and compensating for the time lag difference between direct and reflected routes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ceiling reflection type speaker is used to reproduce audio, then cost is reduced compared to ceiling-mounted speaker, but time lag difference between low and high frequency audio occurs
Solution Approach 1:
The audio signal is segmented into low frequency component and high frequency component using a low-pass filter and high-pass filter respectively. This segmentation allows independent processing of each frequency component to compensate for the time lag difference caused by direct and reflected routes.
Solution Approach 2:
The low frequency component is delayed in advance by a delay processing unit before being combined with the high frequency component. This preliminary delay action compensates for the time lag difference that would otherwise occur during audio reproduction, ensuring synchronized arrival of both frequency components at the listener's position.
2Adaptability or versatility
If ceiling reflection type speaker is used, then installation flexibility is improved, but sense of localization and connection with other channels is lost
Solution Approach 1:
The audio signal is divided into low frequency and high frequency components, allowing separate processing paths. The low frequency component is routed through delay processing while the high frequency component is processed differently, enabling precise control over the timing and spatial characteristics of each frequency band to preserve localization information.
Solution Approach 2:
Different processing treatments are applied to different frequency components: low frequency components receive delay processing to match the reflected route timing, while high frequency components are handled differently. This local quality approach ensures that each frequency component arrives at the listener's position with appropriate timing characteristics, maintaining sense of localization.
3Device complexity
If direct route and reflected route audio are combined without delay compensation, then audio reproduction is simplified, but frequency band separation occurs between low and high frequency
Solution Approach 1:
The audio signal is segmented into low frequency and high frequency components through filtering. This segmentation enables independent timing adjustment of each frequency band, ensuring that despite the different path lengths of direct and reflected routes, both components arrive synchronized at the listener's position, maintaining stable frequency band composition.
Solution Approach 2:
The time delay parameter of the low frequency component is changed (increased) to match the additional path length of the reflected route. By adjusting this temporal parameter, the system compensates for the route difference and maintains proper frequency band composition without requiring complex hardware modifications.
Data Source
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AI summary
PROBLEM: To resolve a problem that a listener feels that sense of localization and sense of connecting with the other channels are lost in case that the listener listens to an audio that is output from a ceiling reflection type speaker in an audio processing device that outputs an analog audio signal to speakers including the ceiling reflection type speaker that makes the audio reflect at a ceiling. SOLUTION: A DSP (5) performs low-pass filter processing that extracts low frequency component from a digital audio signal, high-pass filter processing that extracts high frequency component from the digital audio signal, delay processing that delays the low frequency component of the digital audio signal that is extracted by the low-pass filter processing, and composition processing that composes the low frequency component of the digital audio signal that is delayed by the delay processing and the high frequency component of the digital audio signal that is extracted by the high-pass filter processing as audio signal processing.