Today, fortunately, was much more productive than yesterday. In the morning, I wrote and tested WaveSplitter, a program that splits one wave file into many smaller ones, then runs an FFT on them. (Note: Code used to run FFT and draw graphs was from yesterday, still have to implement changes made to them by partners.) After doing research on the AudioInputStream class, I managed to get my code to read the buffered file and write it out again in chunks (rather than using nested loops, as I had originally planned). Each wave file can be successfully FFT'ed upon. Only problem I discovered was that, if one tried to split the wave file into larger chunks (the default that works is one second) it will only give one second to be analyzed, just space them out more and have fewer mini-files. I'm not quite sure how to fix it, so am waiting until Friday. There was another problem but I can't think of it right now.
This afternoon, I worked on a function to get the peaks from the FFT data generated. This involved a bit of trial-and-error with reading the files in (and the hope that the FFT file generation hasn't changed much today). I wrote a simple loop that goes through the data and gets rid of the smallest half (because they are obviously not large enough peaks to bother with). Running this "cleaner function" multiple times gives the peaks of the data. Comparing the graphs to the numbers, it appears fairly accurate. The only trick will be to translate the location of the peak to a frequency, in order to make this useful for analysis, and be able to write and append this data to a single file, then use the file to generate a graph for the song as a whole (with higher accuracy than taking an FFT of the entire song, as in the latter, small peaks would be lost in the noise, while in the former, smaller peaks are preserved).
Also, as a special tangential issue, I researched some information about logarithmic thinking. I first heard about this on a podcast, RadioLab, done through NPR. They did a special on numbers, and their first story was about how babies and toddlers "think" of numbers.
Found at RadioLab's website.
Basically, there was a study done on babies, children from two to three months old. They were hooked up to an electrode net and shown a series of eight identical pictures, in one case, ducks. They were measured on their reactions when the pictures changed to, say, eight trucks. Then, they changed from eight ducks to sixteen ducks. The babies' brains still showed a change, but in a different area. The study went on to show that babies can tell the difference between large differences of numbers, like ten and twenty, but not smaller ones, like nine and ten.
The reason for this is that, initially, our brains think of numbers logarithmically. The show goes on to tell about studies done among non-counting people living in the Amazon basin, who, when asked what is between one and nine, reply "Three." To us, it makes no sense, as the number directly between one and nine is five (four more than one and four less than nine). But the way they think of it is, one times three is three. Three times three is nine. Therefore, three is exactly between one and nine.
This way of thinking is not unique to infants and non-counters, either. Say, for example, there's a sale on a pair of pants. Normally, the pants cost twenty dollars, but today, they cost ten. That's a really great deal, isn't it? Now say that you find a jacket that's also on sale. It used to be a hundred dollars, but now it's only ninety. Is it as good a deal?
Thinking linearly about it, it seems both these deals are the same. However, half off is far better than ten percent off, and our gut reaction is to say that the pants are a better deal than the jacket. As a third example, if you were thinking of buying a ten thousand dollar car, the salesman knocking ten dollars off the price will probably not sway you much.
This relates to our project with the fact that steps on the western scales are arranged logarithmically. For example, going from middle C to high C doubles the frequency (and halves the wavelength). Now, this has something to do with the waves that make up sounds, as waves that have peaks at similar times will reinforce each other, creating a stronger sound. If wave 1 has half the frequency of wave 2, they will reinforce each other every other wave, whereas if wave A has a wavelength of a hundred less than wave B, there's no telling when they will reinforce each other. However, our brains prefer the reinforced waves, which in turn lead to our appreciation for things "in key." I'm fairly sure it's related to our thinking logarithmically, or perhaps we think logarithmically and like chordes due to some other facet of human nature. Regardless, it's pretty interesting.
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