Audio Dynamics Control Signal Shaping to Reduce Pumping
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Solution Overview
Problem
Existing dynamics processors in audio mixing desks face issues such as 'pumping' and inter-harmonic modulation due to fixed release waveforms, which are not suitable for all audio inputs, leading to unnatural audio envelopes and missed signal transients.
Innovation Solution
A method for generating a control signal using a signal dynamics processor with a sample and hold circuit, shape selector, and release time selector, allowing for customizable attack and release waveforms, particularly enabling an inverse exponential release shape to reduce distortion and erratic level changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fixed release waveforms (linear, exponential) are used in dynamics processors, then the device structure remains simple, but the audio quality deteriorates due to pumping and inter-harmonic modulation effects
Solution Approach 1:
The patent implements dynamic release waveforms that adapt their shape based on the input signal characteristics and selected presets. The release waveform generator dynamically adjusts the release curve between linear and exponential shapes, and can vary the release time based on signal level, thereby eliminating the harmful pumping and inter-harmonic modulation effects while maintaining operational simplicity through automated adaptation.
Solution Approach 2:
The system changes the release waveform parameters (shape and time) based on different operating conditions. Multiple release waveform shapes are available including linear, exponential, and custom shapes, with release times that can be adjusted independently. This parameter variability allows optimization of audio quality for different input types while keeping the device structure manageable through software-based waveform generation.
2Speed
If faster release times are used to improve responsiveness to signal transients, then the device becomes more responsive, but audio quality deteriorates due to unnatural envelopes and pumping effects
Solution Approach 1:
The release waveform generator dynamically adapts the release curve shape and time based on the instantaneous signal level and characteristics. During fast transients, the system can employ shorter release times to maintain responsiveness, while automatically adjusting the waveform shape to prevent pumping. The dynamic nature of the release waveform allows it to optimize between speed and naturalness in real-time.
Solution Approach 2:
The system uses periodic analysis of the input signal to determine appropriate release parameters. By continuously monitoring signal characteristics and adjusting release waveforms in periodic intervals, the system maintains responsiveness to transients while preventing the buildup of unnatural envelopes and pumping effects that occur with fixed release settings.
3Device complexity
If linear fixed gradient release is used, then the device structure remains simple, but the release time varies with signal level causing inconsistent audio behavior
Solution Approach 1:
The system implements release time parameter changes based on signal level detection. Different release times are assigned to different signal level ranges, ensuring that the release behavior remains consistent and predictable across varying input levels. This parameter adaptation is managed through software algorithms that automatically select appropriate release parameters, maintaining stability without requiring complex hardware circuitry.
Solution Approach 2:
The release waveform generator incorporates feedback from the signal level detector to continuously monitor input amplitude and adjust release parameters accordingly. This feedback mechanism ensures that release time remains consistent relative to the signal level, preventing the inconsistent audio behavior associated with fixed gradient releases while maintaining manageable device complexity through software-based control.
4Manufacturing precision
If customizable release waveforms are implemented to improve audio quality, then audio processing quality improves, but device complexity increases
Solution Approach 1:
The patent replaces complex hardware circuitry with software-based waveform generation and processing. The release waveform generator, sample and hold circuits, and signal level detection functions are implemented through digital signal processing algorithms rather than dedicated analog circuits. This substitution maintains high audio processing quality through precise software control while reducing overall device complexity and improving flexibility for future updates.
Solution Approach 2:
The control signal generation system is designed with multi-functionality, where a single integrated release waveform generator can produce multiple waveform shapes (linear, exponential, custom) and adapt to different signal types and applications. This universal approach consolidates what would otherwise require separate hardware circuits for each waveform type, thereby improving audio processing quality while keeping the device structure manageable through software-based multi-functionality.
Data Source
AI summary
Components may modify an audio input signal to produce an output audio signal. The audio input signal is firstly rectified and sent to the peak detector as an input control signal. The peak detector produces a peak value which correlates to the level of the input control signal. The control signal is then sent from the peak detector to a dynamic curve module, which has two user selectable inputs: a threshold level and a knee/dynamic angle. The control signal is then sent from the dynamic curve module to the signal dynamics processor. This processor is then configurable to modify the control signal by applying an attack and release phase waveform to elements of the signal which exceed the threshold set by the user. The user will have selected the release time and the release phase shape prior to use of the processor. The release shape is selected by the user.