Time-Frequency Audio Mixing for Clear Priority Signals
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Solution Overview
Problem
Conventional mixing devices struggle to achieve a finely adjusted mixing process on both time and frequency domains, leading to inadequate clearness of sound sources and causing stress for listeners due to volume fluctuations.
Innovation Solution
A mixing device that converts input signals from the time domain to the frequency domain, allowing for a mixing process on a time-frequency plane, where signal data is processed with priority operations on amplitude and phase to enhance the clearness of priority signals without burying non-priority signals, using techniques like short-time Fourier Transform and sound presence judgment distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If linear filter is used to attenuate frequency band of one sound source, then clearness of that sound source is improved, but energy of other sound sources in same frequency band is reduced causing damage to music quality
Solution Approach 1:
The patent applies local quality by selectively processing only specific time-frequency regions where masking occurs. Instead of globally attenuating entire frequency bands, the system identifies and processes only the specific time-frequency points where the priority sound source is masked by non-priority sources, preserving energy in other regions while improving clearness where needed.
Solution Approach 2:
The patent segments the audio signal into multiple frequency bands using filter banks and processes each band independently in the time-frequency domain. This segmentation allows selective attenuation of masked components in specific frequency bands without affecting other bands, resolving the contradiction between improving clearness and preserving overall energy.
2Measurement precision
If ducker is used to attenuate volume of non-priority sound sources, then clearness of priority sound source is improved, but listener feels stress due to instantaneous volume changes
Solution Approach 1:
The patent implements dynamic control of attenuation amounts based on the degree of masking detected in each time-frequency region. Rather than applying fixed or instantaneous attenuation, the system dynamically adjusts attenuation levels according to the actual masking conditions, smoothing out abrupt volume changes while maintaining clearness of priority sources.
Solution Approach 2:
The patent performs preliminary analysis of the time-frequency characteristics of both priority and non-priority sound sources before applying attenuation. By pre-identifying masking regions and calculating appropriate attenuation amounts in advance, the system avoids instantaneous volume changes that cause listener stress while still achieving clearness improvement.
3Ease of operation
If conventional mixing process is used without time-frequency domain processing, then device complexity is reduced, but finely adjusted mixing process on both time and frequency domains cannot be achieved
Solution Approach 1:
The patent replaces conventional mechanical/analog mixing methods with digital signal processing in the time-frequency domain. By using digital filter banks and computational algorithms to analyze and process signals, the system achieves fine adjustment capabilities that would be impossible with traditional mixing consoles, accepting increased computational complexity for superior mixing precision.
Data Source
AI summary
A mixing device includes a signal data generation unit that generates signal data on a time-frequency plane composed of a time-axis and a frequency-axis from each of two or more input signals derived from a time domain, a signal processing unit that receives the signal data for the two or more input signals, and performs a mixing process that includes an adding operation of the signal data for each corresponding point on the time-frequency plane of the signal data for each of the input signals, and an output signal generation unit that receives the operation result of the signal processing unit and outputs an output signal formed by converting the inputted signal into a signal of a predetermined format.