Frequency-Subband Reverberator With Variable Loop Delays
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Solution Overview
Problem
Current reverberation algorithms primarily function in the time domain, making them impractical for applications that require frequency domain processing, and they lack flexibility in designing frequency-dependent reverberation times essential for human spatial perception.
Innovation Solution
A feedback delay loop processor that delays and combines different frequency subband signals with varying loop delays to produce reverberated signals, allowing for flexible control of reverberation times and energy decay, while maintaining computational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If time domain reverberation algorithms are used, then reverberation can be achieved, but they are impractical for frequency domain processing applications and lack flexibility in frequency-dependent reverberation times
Solution Approach 1:
The audio signal is divided into multiple frequency subbands using a filter bank, with each subband processed independently through its own feedback delay loop. This segmentation allows frequency-dependent reverberation control while maintaining computational efficiency, as each subband can have customized loop delays and feedback gains tailored to specific frequency ranges.
Solution Approach 2:
The invention transitions from time domain processing to frequency domain processing by applying a filter bank decomposition. This dimensional change enables independent control of reverberation parameters across different frequency dimensions, allowing frequency-dependent reverberation times and avoiding the limitations of uniform time domain approaches.
2Ease of operation
If uniform loop delays are applied to all frequency subbands, then implementation is simple, but repetition effects occur that degrade audio quality
Solution Approach 1:
Different loop delays are assigned to different frequency subbands based on their specific characteristics. Lower frequency subbands may use longer delays while higher frequency subbands use shorter delays, creating locally optimized reverberation for each frequency region. This local quality approach prevents the repetition effects that occur with uniform delays while maintaining manageable complexity through systematic variation.
Data Source
AI summary
A reverberator for reverberating an audio signal includes a feedback delay loop processor for delaying at least two different frequency subband signals representing the audio signal by different loop delays to obtain reverberated frequency subband signals.