Real-Time Polyphonic Guitar Harmony Control Signal
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Solution Overview
Problem
State-of-the-art harmony processors are limited in their ability to process real-time harmony signals from polyphonic instruments like guitars, as they rely on monophonic control signals and require batch processing to derive tone, volume, and pitch information, which is not directly available from analog instruments like guitars.
Innovation Solution
A method that generates a harmony control signal in real-time by extracting relevant information from both guitar and voice audio input signals, using a combination of A/D conversion, down-sampling, and MIDI communication to create a polyphonic voice signal, allowing for live performance applications with minimal delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If batch processing is used to derive tone, volume, and pitch information from guitar audio signals, then measurement precision is improved, but processing time increases significantly
Solution Approach 1:
The patent segments the guitar audio signal into individual note components using constant Q-transform and spectral analysis. By dividing the complex polyphonic signal into separable note elements, the system can extract tone, volume, and pitch information from each note independently and simultaneously, achieving batch-processing accuracy without sequential processing delays.
Solution Approach 2:
The patent performs preliminary signal processing by applying constant Q-transform and spectral analysis to pre-process the guitar audio signal into a structured representation. This preliminary action organizes the signal data in advance, making subsequent tone, volume, and pitch extraction operations faster and more efficient, thereby reducing overall processing time while maintaining precision.
2Productivity
If real-time harmony processing is implemented, then productivity is improved, but device complexity increases due to the need for voice input and simultaneous analysis
Solution Approach 1:
The patent creates a universal harmony processing system that can handle multiple input types (guitar audio signals and voice signals) through a single integrated processing pipeline. The constant Q-transform and spectral analysis methods work uniformly across different input sources, allowing the system to process guitar chords and voice melodies simultaneously without requiring separate processing paths, thereby reducing overall system complexity.
Solution Approach 2:
The patent introduces an intermediary representation layer (spectral analysis results and note detection data) that mediates between the raw audio inputs and the harmony processing functions. This intermediary layer standardizes the input data format, allowing different audio sources to be processed through common harmony generation algorithms, simplifying the overall system architecture while enabling real-time processing.
3Adaptability or versatility
If polyphonic guitar signals are processed to extract control information, then adaptability is improved, but measurement precision deteriorates due to signal overlap and analysis difficulty
Solution Approach 1:
The patent employs dynamic signal processing by adjusting the Q-factor and analysis parameters based on the instantaneous characteristics of the polyphonic guitar signal. The constant Q-transform dynamically adapts to different frequency content and temporal structures of guitar chords, allowing precise separation and measurement of individual notes even when they overlap in frequency and time, thereby maintaining high measurement precision across diverse polyphonic inputs.
Data Source
AI summary
The invention relates to a method of establishing a harmony control signal controlled in real-time by a guitar audio input signal (GAS), comprising the steps ofproviding a first input harmony input control signal (FIH) on the basis of said guitar audio input signal (GAS),providing a second input harmony control signal (SIH) on the basis of a voice audio input signal (VAS).providing an input audio extraction representation (IAER) on the basis of said first input harmony input control signal (FIH),establishing a harmony control signal (HCS) on the basis of said input audio extraction representation (IAER) and said second input harmony control signal (SIH).