Electronic Measuring Device for Stringed Instrument Tuning

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Solution Overview

Problem

Stringed musical instruments often go out of tune due to atmospheric changes, particularly humidity, causing beating sounds from interference among harmonic frequencies, which existing tuning methods struggle to address effectively.

Innovation Solution

An electronic measuring device calculates the difference in harmonic frequencies of each string, providing feedback to adjust tensions and optimize tuning, using a mathematical model and Fast Fourier Transform to minimize beating effects by determining an optimal tuning curve based on individual string properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional tuning methods are used, then tuning process is simple, but beating sounds occur due to harmonic frequency interference

Engineering Contradiction:
Improvetuning process simplicityVSAvoidbeating sounds
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The system captures audio samples of the instrument strings, performs spectral analysis to identify harmonic frequencies, calculates beating effects between harmonics of different strings, and provides feedback to the tuner about optimal tuning adjustments. This closed-loop feedback mechanism enables precise elimination of beating sounds while maintaining ease of operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary spectral analysis and calculates optimal tuning targets before the actual tuning adjustment. By pre-calculating the ideal frequencies that will eliminate beating effects based on the instrument's specific characteristics, the system guides the tuning process to achieve optimal results without trial and error.

Inventive Principle:
Principle #10Preliminary action

2Object-generated harmful factors

If harmonic frequency alignment is optimized, then beating effects are reduced, but measurement and calculation complexity increases

Engineering Contradiction:
Improvebeating effectsVSAvoidmeasurement and calculation complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The system replaces complex manual measurement and calculation processes with automated electronic signal processing. A microphone captures acoustic signals, which are then processed through Fast Fourier Transform algorithms to automatically identify harmonic frequencies and calculate beating effects, eliminating the need for manual spectral analysis while achieving precise harmonic alignment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system automatically performs spectral analysis, identifies harmonic frequencies, calculates beating effects, and determines optimal tuning targets without requiring the tuner to manually perform these complex measurements. The instrument itself provides the test signals by being played, and the system self-calibrates based on the captured acoustic data.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If individual string properties are considered, then tuning precision is improved, but time required for tuning increases

Engineering Contradiction:
Improvetuning precisionVSAvoidtuning time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system captures audio samples continuously or in rapid succession, performing spectral analysis on each sample to track frequency drift over time. By continuously monitoring the instrument's acoustic properties and providing real-time feedback, the system achieves high precision tuning without requiring multiple separate measurement sessions, thereby reducing total tuning time.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system performs preliminary spectral analysis on individual strings to identify their specific harmonic characteristics and inharmonicity factors before calculating the overall tuning optimization. By pre-characterizing each string's properties, the system can quickly determine optimal tuning targets that account for individual string variations without time-consuming iterative adjustments.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The device effectively reduces audible beating by calculating and adjusting string frequencies to align harmonic components, ensuring precise tuning and adaptability to environmental changes, enhancing the stability and sound quality of stringed instruments.

Implementation Method 1

A Fast-Fourier Transform is provided to perform note detection, coupled to a frequency band based partial measurement.

Methodology Applied
Scientific EffectFast Fourier Transform:

Implementation Method 2

an interference among the harmonic frequencies of the multiple notes may cause a beating effect

Methodology Applied
Scientific EffectAcoustic interference: Interference

Implementation Method 3

A vibrating string produces vibrations at a number of frequencies above the fundamental pitch of the corresponding note. These vibrations may be referred to as overtones, or as harmonics when the overtones are at integer multiples

Methodology Applied
Scientific EffectHarmonic oscillation: Harmonic Oscillator

Data Source

PatentEP3350799B1Electronic measuring device
Publication Date: 2020.05.20 MULTIPITCH INC
  • EP3350799B1 patent drawingFigure 1
  • EP3350799B1 patent drawingFigure 2
  • EP3350799B1 patent drawingFigure 3A~3F

AI summary

An electronic measuring device captures a plurality of audio samples, wherein each audio sample corresponds to a different string of a musical instrument. The device further identifies a plurality of frequency components of each of the plurality of audio samples, calculates an optimal tuning curve based on the plurality of frequency components of each of the plurality of audio samples, and determines a deviation of the plurality of frequency components of each of the plurality of audio samples from the optimal tuning curve.