This is a program that can compare two sounds by finding an envelope of the frequency waveform of each of the two sounds and subtracting them from each other. Up to 4 pairs of sounds can be checked simultaneously.
Summary
This program is to find out what the difference between two sounds is in terms of frequency. In common sense, you can calculate the frequency waveforms of two sounds and then perform the subtraction operation. However, in reality, the frequency waveform is too complex and error-prone, so practical use is almost impossible. To solve this problem, this program uses the method of finding the envelope of the frequency waveform and then calculating the difference (subtraction operation) between the two envelopes.
When there are two sounds, A and B, an analysis method that checks the difference between A and B by obtaining an envelope of the frequency waveforms of A and B and then performing a subtraction operation between them is a method that no one has tried yet. Therefore, since the term referring to the subtraction result graph also does not exist yet, the envelope subtraction result graph of these frequency waveforms is named 《HIS Graph》 and the characteristic shown in the 《HIS Graph》 is named 《HIS Characteristic》.
I first tried this method as a graduation thesis when I was attending the Cremona violin making school. At that time, the main purpose was to determine the realization or applicability of this analysis method, so it was produced as a simple CLI (Command Line Interface) program. However, since the CLI program is difficult to use, it has been improved as a GUI (Graphical User Interface) program that can be used more easily.
To briefly explain the technical process, when there are two sounds A and B,
Obtain the frequency waveform (FFT: Fast Fourier Transform) of A.
Find the envelope(LPC Spectral Envelope) of the frequency waveform of A obtained above.
B does the same.
Subtract the envelope of the frequency waveform of B from the envelope of the frequency waveform of A to find the difference between the two.
They are calculated in this order. There are several methods such as LPC and MFCC to obtain the envelope of the frequency waveform, but the well-known LPC method is used here.
Usage
You can use both if you need to compare two sounds, or if you want to know the change or difference between two sounds.
For example, in the case of a violin,
Change of sound according to position of the sound post
Change of sound according to shape change of bridge
Change of sound according to string replacement
etc., and can be applied in various ways if sound comparison is necessary.
In addition, the purpose of the development of this program and the most important use is a case of finding the acoustic characteristics of violin body (excluding strings)
In other words, it is to find out how the vibration of the strings is amplified (or attenuated) as it passes through the violin body, in other words, what acoustic (amplification) characteristics the violin body has. (This study was the subject of my graduation thesis, so it will be reorganized and published later.)
There are several ways to check the acoustic characteristics of a violin, but each has a big problem. Among them, the tap-tone method checks the resonance of the instrument, so it cannot explain other frequency bands than the resonant frequency. For example, if we assume that resonance is confirmed in the 1kHz band, we can predict that the sound will be loud in that band, but we cannot know what happens in other frequency bands. The way to analyze the actual sound of a violin is that the sound changes depending on the type of string, so it is difficult to say that it is the original acoustic characteristics of the violin. Solving the problems of these existing methods is the most important purpose and use of this program.
I have listed only a few uses for the violin, but depending on the idea, it can be said that the uses are limitless. It can be used wherever you want to compare the sound of not only the violin, but also other instruments such as guitar, piano, and harp.
Install
Since this program is a portable version, no installation work is required.
After unpacking, double-click the 《Sound_Comparing_Analyzer_v.X.X.X.exe》 file in the 《Sound_Comparing_Analyzer_v.X.X.X》 folder to run the program immediately. However, it may take a long time to run depending on the specifications of your computer.
HIS Graph and HIS Characteristics
The characteristics appearing in the 《HIS Graph》 can be classified into the following 5 types. (Details will be explained in a separate report later)
Division Name Discrimination Explanation
Section Live Zone Value > 0 Amplification section
Suspended Zone Value ≒ 0 No change section
Dead Zone Value < 0 Attenuation section
Point Live Spot Pointed up Point of local amplification
Dead Spot Pointed down Point of local attenuationFor Live/Suspended/Dead Zone, if the value of the section is positive, it is Live, if it is close to 0, it is Suspended, and if it is negative, it is judged as Dead Zone. Live/Dead Spot is determined by whether the shape of the curve is pointed upward or downward.
(See picture below)
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