Axtell's Notes: June 11

Today has been massively productive. First off, the doFFT() method (from JASS) has been replaced with Sonogram's method because it does not write over the array that it is given, as the JASS method does.

It also returns a more accurate array of data without any negative values. Because there are no longer negative values, the graph has been reformatted to only show the positive x- and y-axises. On the graphing side of things, the FFT graph now displays the frequency in megahertz (MHz). I hope to set up a feature that will display the frequency of a peak in hertz when hovered over/clicked on.

I also discovered that the windowing functions have been working, but because the graphing class scales each set of data to fill the graph, the difference couldn't be seen. When called in comparison, the four FFTs (FFT and three different windowed FFTs of the same file) appear on top of each other in different colors and in the same scale.

Windowed FFT Comparison

(Click on the image for a larger version)

Red = unwindowed FFT
Blue = Bartlett window
Green = Hamming window
Yellow = Hanning window

I will be working on changing which window is in front through some buttons or clicking on the graph.

Another update to the graphs is that if multiple windows are open at once, closing one does not close all of them and does not end the program.

The next step will be to combine this now working code with Tayloe's wave splitting code to make FFTs (windowed or not) of much shorter sound files (512 samples so much shorter than one second).

Next week I will also continue update the GraphingData class, and work on adding a function that will plot the sound file given on a graph (x-axis as time, y-axis as amplitude). So if the sound file given were a single sustained note, it would graph a sine curve.