Dynamic Volume Control for Consistent Tonal Balance
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Solution Overview
Problem
Conventional sound reproduction systems fail to accurately maintain tonal balance when sound is played at levels different from the reference level, leading to a degraded listening experience due to the inability to apply continuous and accurate equal loudness correction.
Innovation Solution
A dynamic volume control system using 2nd order biquad filters that continuously adjust sound characteristics to match the reference level, implemented in a surround sound system, ensuring that sound reproduced at any level maintains a consistent tonal balance by employing low and high-frequency boost shelves with adjustable parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fixed filters are used to boost bass or bass and treble, then tonal balance can be improved at specific volume levels, but the solution cannot continuously adapt to varying volume levels and cannot apply accurate equal loudness correction
Solution Approach 1:
The patent implements dynamic volume control that continuously adjusts filter characteristics based on the current playback level. The system transitions from fixed filters to dynamically adjustable filters that adapt their frequency response in real-time according to the volume setting, enabling accurate equal loudness correction at any playback level by calculating the difference between current and reference levels.
Solution Approach 2:
The system changes filter parameters (frequency, gain, Q-factor) dynamically based on the playback level. By continuously monitoring the volume control position and calculating the deviation from reference level, the system adjusts filter parameters to compensate for tonal imbalances, transforming static filter characteristics into adaptive ones that maintain accurate tonal balance across all volume settings.
2Ease of operation
If sound is reproduced at levels different from the reference level, then volume flexibility is improved, but tonal balance deteriorates due to inability to apply continuous equal loudness correction
Solution Approach 1:
The system employs feedback by continuously monitoring the current playback level and using this information to adjust filter characteristics. The volume control position serves as feedback input that drives the dynamic adjustment of equal loudness filters, creating a closed-loop system that automatically compensates for tonal imbalances caused by deviations from reference level playback.
Solution Approach 2:
The system performs preliminary calculation of the required filter adjustments based on the detected playback level deviation from reference. Before the user perceives any tonal imbalance, the system has already computed and applied the appropriate filter characteristics to pre-correct the frequency response, ensuring tonal accuracy is maintained proactively across all volume settings.
Data Source
AI summary
A constant balance volume control according to the present disclosure may provide a user with the ability to listen to program material originally mixed at a known “reference” level at any other suitable level without experiencing a substantial shift in tonal balance. A constant balance volume control may include two 2nd order biquad filters that are controlled in a continuous manner by the volume control of a system. The filters could be implemented in analog or digital form.