Basic method to graph amplitude of a single frequency over time?

[mikejm]

If you have an audio clip of a simple modal instrument like a plucked guitar string and want to graph the amplitudes a given partials over time, how would you go about it?

Eg. This is a basic raw pluck response of a guitar string in Izotope RX:


Let's say I want to graph the amplitude of a given modal frequency over time.

I presume I need to run an FFT window centered around the target frequency. I think I can do this even from Izotope RX just by selecting everything away from the mode I want and deleting it:



Is this essentially the right approach? It's not perfect because you can never window perfectly I suppose without keeping some dirt or attenuating your desired freq, but it seems to do the job pretty well.

How might I next get the amplitude of this frequency range over time so I can graph it, eg. in Excel/Sheets?

I know some basic JUCE/C++ but mainly for building synths. I've never done anything like this. Thanks.

[mikejm]

I figured out I can just change the view which I think gives me what I want:

eg. Here is partial 7:

https://i.postimg.cc/50JJ8ZHP/7-large.png

Any other approach?