Adaptive Amplifier Gain for Preserving Audio Dynamics
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Solution Overview
Problem
Existing audio amplification systems struggle to maintain dynamic sound levels, often resulting in artifacts like pumping or distorted musical content, as they aim to keep the average sound level constant across varying audio signals, failing to differentiate between quiet dialogues and action scenes.
Innovation Solution
A method and amplifier system that calculates a normalized total slow sound level and peak sound level to determine adaptive volume gains, allowing the sound level to evolve within pleasant proportions by adjusting the slow and peak volume gains based on desired settings, ensuring listening quality and dynamics are maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If automatic gain control is applied to maintain constant average sound level, then sound level stability is improved, but audio signal dynamics are distorted and artifacts are introduced
Solution Approach 1:
The patent applies dynamics by making the gain control adaptive rather than static. The system dynamically adjusts the gain based on the detected sound level, using different gain values for different input levels. This allows the system to maintain stability for quiet signals while preserving the dynamic range for louder signals, thus resolving the contradiction between stability and dynamics preservation.
Solution Approach 2:
The patent changes the gain parameter based on the detected sound level characteristics. By monitoring the sound level and adjusting the gain parameter accordingly, the system maintains constant average sound level for stability while adapting the gain to preserve the natural dynamics of the audio signal, avoiding the distortion introduced by fixed gain control.
2Ease of operation
If aggressive gain adjustment is used to maintain constant sound level, then sound level control is improved, but musical content and scene differentiation are lost
Solution Approach 1:
The patent applies partial action by using gentle, progressive gain adjustments rather than aggressive corrections. The gain modification is applied gradually and proportionally to the detected sound level deviations, which maintains effective sound level control while preserving the musical content and scene differentiation that would be lost with aggressive adjustment.
3Ease of operation
If simple gain reduction is applied during loud passages, then peak level control is improved, but overall listening quality deteriorates
Solution Approach 1:
The patent applies local quality by applying gain adjustment selectively based on the local characteristics of the audio signal. Instead of uniform gain reduction, the system adjusts gain locally according to the detected sound level at each moment, preserving listening quality during loud passages while maintaining peak level control. This localized approach ensures that only necessary adjustments are made, preserving overall audio fidelity.
Data Source
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AI summary
The invention relates to a method for adapting the volume gain (GVolume appliqué) to be applied by an amplifier to at least one audio signal (SAudio 1 to SAudio N) to be reproduced, according to the desired volume gain (GVolume désiré) selected by a user, said method comprising the steps of: calculating a standardised total slow sound level (NSLTN) from the at least one signal (SAudio 1 to SAudio N) to be reproduced; calculating a maximum slow volume gain (GVolLentMax) and a minimum slow volume gain (GVolLentMin) as the quotient of the product of the desired volume gain (GVolume désiré) by dividing a maximum slow gain (GLentMax) or respectively a minimum slow gain (GLentMin) by the standardised total slow sound level NSLTN); determining a first minimum out of the desired volume gain (Gvolume désiré) and the maximum slow volume gain (GVolLentMax); determining a second minimum out of the desired volume gain (GVolume désiré) multiplied by a maximum volume gain (GmaxVolume) and the minimum slow volume gain (GvolLentMin); determining, as a slow volume gain (GVolume Lent), the maximum of the first and second previously determined minima; and calculating the volume gain applied (GVolume appliqué) according to the slow volume gain (GVolume Lent).