Wind Instrument Mute Signal Processor for Frequency Distortion Correction

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Solution Overview

Problem

Conventional sound systems for wind instruments with mutes distort sound characteristics, causing unnatural operation noise, uncomfortable noise, and high-frequency disturbances when players listen through earphones, as they fail to correct changes in frequency characteristics caused by the mute.

Innovation Solution

A signal processor that converts and processes electric signals from a wind instrument played with a mute to cancel changes in frequency characteristics, using a FIR filter and filtering coefficients to simulate the sound characteristics of the instrument without the mute, allowing players to hear sounds similar to those produced without the mute.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a mute is attached to the wind instrument to reduce volume, then the volume of sounds emitted to the outside is reduced, but the frequency characteristics of the sound change causing unnatural operation noise and high-frequency disturbances

Engineering Contradiction:
Improvesound volumeVSAvoidfrequency characteristic distortion
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

A signal processor is introduced as an intermediary between the microphone and the player's earphones. This signal processor applies filtering coefficients to correct the frequency characteristics of the sound signal, removing the harmful distortions caused by the mute while preserving the volume reduction benefit

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The signal processor changes the frequency distribution parameters of the sound signal by applying filtering coefficients. These coefficients are designed to compensate for the specific frequency changes caused by the mute, restoring natural sound characteristics despite the presence of the mute

Inventive Principle:
Principle #35Parameter changes

2Loss of information

If conventional signal processing is used to control sound image position, then the localization of sound image is improved, but the frequency characteristic changes caused by the mute are not corrected

Engineering Contradiction:
Improvesound localizationVSAvoidfrequency characteristic accuracy
Core Design Contradiction:
Loss of informationVSManufacturing precision

Solution Approach 1:

The signal processing function is segmented into two independent components: sound image localization processing and frequency characteristic correction processing. The filtering coefficient processing specifically targets frequency characteristic accuracy, while separate processing maintains sound localization, allowing both functions to optimize their respective goals

Inventive Principle:
Principle #1Segmentation

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 signal processor effectively cancels frequency changes caused by the mute, enabling players to comfortably listen to sounds similar to those produced without the mute, reducing operation noise and high-frequency disturbances.

Implementation Method 1

the signal processing circuit processes the electric signal on the basis of a transfer function

Methodology Applied
Scientific EffectConvolution operation:

Data Source

PatentEP2713365B1Signal processor for musical performance of wind instrument using a mute
Publication Date: 2018.01.31 YAMAHA CORP
  • EP2713365B1 patent drawingFigure 1~2
  • EP2713365B1 patent drawingFigure 3(A)~3(C)
  • EP2713365B1 patent drawingFigure 4(A)~4(C)

AI summary

A mute unit 20 is attached to a trumpet. Inside the mute unit 20, a microphone 21 is mounted, so that a sound collected by the microphone 21 is converted to an electric signal. The electric signal is supplied to a signal processor 30. The signal processor 30 processes the electric signal converted by the microphone 21 such that changes in frequency characteristic of the sound caused by the mute unit 20 are cancelled. The signal processor 30 then outputs the processed signal.