Audio Volume Control Using Short- and Long-Term Level Correction
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Solution Overview
Problem
Audio devices struggle to maintain consistent volume levels when switching between different audio sources or formats, such as CDs, DVDs, radio tuners, and portable players, due to varying recording formats and volume settings, requiring frequent manual volume adjustments.
Innovation Solution
An acoustic processing device that generates both short-term and long-term signal level variation signals, allowing for rapid and slow variation corrections through combined control signals to maintain optimal volume levels independently of the audio encoding format or source type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different audio encoding formats are used for different media (CD, DVD, radio), then each format can be optimized for its specific medium, but the volume level varies significantly across formats requiring frequent manual adjustment
Solution Approach 1:
The audio device automatically detects the audio source type and encoding format, then autonomously adjusts volume parameters without requiring manual user intervention. The system serves itself by implementing automatic gain control and format identification algorithms that adapt the volume settings based on the detected source characteristics
Solution Approach 2:
The device dynamically changes volume parameters based on the detected audio format and source type. By monitoring audio signal characteristics and automatically adjusting gain parameters, the system maintains consistent perceived volume across different encoding formats while preserving format-specific audio quality
2Adaptability or versatility
If the category of music or video is changed, then the content variety is improved, but the volume control operation becomes more frequent and complex
Solution Approach 1:
The system pre-establishes volume profiles for different content categories (action movies, classical music, rock music, etc.). When a category change is detected, the device retrieves and applies the corresponding pre-configured volume parameters, eliminating the need for real-time manual adjustment and reducing user time loss
Solution Approach 2:
The device continuously monitors audio signal characteristics and provides feedback to automatically adjust volume settings. By detecting changes in content category through audio analysis, the system triggers automatic volume adjustments without requiring user input, creating a closed-loop control system that adapts to content changes
3Adaptability or versatility
If both portable audio player volume control and on-vehicle audio apparatus volume control are considered, then compatibility with external sources is improved, but the volume control operation requires multiple adjustments
Solution Approach 1:
The device merges the volume control functions of the portable audio player and on-vehicle audio apparatus into a unified control system. By implementing a master volume control mechanism that coordinates both devices, the system eliminates the need for separate adjustments and simplifies the overall control architecture
Solution Approach 2:
The on-vehicle audio apparatus acts as an intermediary device that receives audio signals from the portable player and applies centralized volume control. This mediator function allows the vehicle audio system to override or coordinate with the player's volume settings, ensuring consistent control and reducing the need for multiple adjustments
Data Source
Figure 1
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Figure 3(a)~3(b)
AI summary
There is provided an acoustic processing device capable of maintaining volume and reproducing audio signals with good sound quality independent of the media audio encoding format, sound source type or sound source volume setting. In the acoustic processing device (1), a limiter control signal generation section (5) generates a limiter control signal for applying rapid variation correction determined based on a short-term signal level variation of an audio signal of a sound source and slow variation correction determined based on a long-term signal level variation of the audio signal of the sound source, and volume control sections (7) and (8) apply the generated limiter control signal to the audio signal and control the volume of the sound source.