Dynamic Audio Enhancement Using Headroom-Based Gain Control
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Solution Overview
Problem
Compact portable audio devices with limited dynamic range struggle to enhance bass and treble without causing distortion or damaging electro-dynamic systems, as existing algorithms require significant processing power and are not suited for low-cost, compact equipment.
Innovation Solution
An audio processor that splits the audio signal into frequency bands, calculates dynamic headroom, and applies a gain to enhance bass and/or treble, using a previous enhancement gain value to predict and avoid clipping, thus allowing for significant boost without distorting the sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a linear boost of bass and treble is applied, then the frequency response is improved, but distortion increases and the electro-dynamic system may be damaged
Solution Approach 1:
The patent applies dynamic gain adjustment where the enhancement gain is continuously adapted based on the available dynamic headroom calculated from the audio signal characteristics. This allows the system to provide frequency enhancement while dynamically preventing distortion by reducing gain when the signal approaches clipping levels.
Solution Approach 2:
The patent implements a feedback mechanism where the output signal is monitored to calculate the available dynamic headroom, which then feeds back to adjust the enhancement gain. This closed-loop control ensures that enhancement is applied without causing distortion or damage to the electro-dynamic system.
2Manufacturing precision
If complex algorithms are used for signal enhancement, then the enhancement quality is improved, but the processing power requirement increases making it unsuitable for compact low cost equipment
Solution Approach 1:
The patent segments the audio signal into different frequency bands (bass and treble) and applies enhancement separately to each band. This segmentation allows for simpler processing of each band independently while achieving overall high-quality enhancement suitable for compact devices.
Solution Approach 2:
The patent changes the parameter being controlled from fixed gain to dynamic gain based on available headroom. This parameter change simplifies the algorithm by using straightforward calculations based on signal level measurements rather than complex real-time optimization, reducing processing requirements while maintaining enhancement quality.
3Power
If the full dynamic range is utilized for enhancement, then the boost effect is maximized, but clipping distortion occurs due to response time delay in detecting and reducing the level
Solution Approach 1:
The patent calculates the available dynamic headroom in advance based on the current signal level and enhancement gain before applying the enhancement. This preliminary calculation allows the system to adjust the gain proactively to prevent clipping rather than reacting after clipping occurs, eliminating distortion caused by response time delay.
Data Source
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AI summary
An audio processor for generating an audio output signal (Y) with an enhanced spectral component compared to an audio input signal (X). The processor comprises a frequency splitter (FS) for splitting the input (X) into first and second parts (X1, X2) representing different frequency bands. A gain calculator (GC) estimates a level (LY) of the enhanced audio output signal (Y) for a case where the first signal part (X1) is gained by a previous enhancement gain value (LG). A dynamic headroom (HR) available is calculated based on the estimated level (LY). An enhancement gain (G) is then calculated based on the available dynamic headroom (HR), and this enhancement gain G is applied to the first signal part (X1), and finally the enhanced output signal (Y) is generate by combining the enhanced signal part (ESP) and the second signal part (X2). Preferably, the enhancement gain G calculation is updated for each signal sample, thus allowing fast adjustments of the gain G to avoid clipping distortion. The audio processor is suited to provide bass and/or treble enhancement and it provides a high utilization of the dynamic range available without audible artefacts. Still, the algorithm is simple to implement and is thus suited for enhancing audio performance of compact low cost devices.