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Using Sonic Visualiser (assign 3)

September 10, 2009

I chose the sounds of an ocarina, a typewriter, wind chimes, and an owl. (photos in photobucket)

For the spectrogram, I chose a window size that allowed me to see as many of the horizontal lines (representing the various frequencies) and the spacing between them as clearly as possible. Thus, my colours were usually default (green on black) and my scale set to “meter.” Window size 2048 generally gave the best compromise between line visibility and line thickness. For the spectrum, my main parameter/graphing decision involved choosing the plot type, which I set to “colors,” since such a method of display best helped me, personally, understand what was going on. Graphed this way, the spectrum is now the same as the spectrogram, just turned to the side, and from it, i can see every frequency present and its amplitude. Dragging the sound file so that the spectrum is recalculated for every point reveals, as expected, the fundamental frequency (if it is present)(since this is the frequency whose amplitude is rather great and relative consistent throughout the duration of the sound.)

Starting with the ocarina was a good idea, since it is the most straightforward. There is an obvious fundamental frequency and its multiples visible. The fundamental frequency does not change, reflected in the constant and unchanging pitch of the instrument within the time it is blown.
The owl sound has a sonic structure quite similar to that of the ocarina – a fundamental frequency and its multiples, all of which stay fairly consisten over time. The horizonal lines in the owl sound spectrometer were, of course, less “straight” than those in the ocarina diagram, a little more curved. Which is understandable because the owl is a breathing, living object, so its sound cannot be as mechanical and precise.
The typewriter was a clear stand-out, since it among the four lacked “pitch” and thus any real fundamental frequency. For the typewriter, all frequencies are at approx. equal volume (I can tell from the spectrum); no one frequency is distinct or consistently “reinforced.” Looking at the spectrometer in this case, the display of the time of the “entrance” of various frequencies is pristine. Because the typewriter’s sounds consists of brief, sharp, attacks, this makes sense. As expected, the frequency (the horizonal lines) are very blurry, simply because they are not there…the frequencies don’t last in a typewriter sound!
The graphs for the wind chime were interesting. Apparently, there is a fundamental frequency in the windchime, but it is relatively pure – most of its partials (or overtones) are not present at first, coming in one or two at a time later on, instead of all at once. And once a partial or multiple frequency settles in, it stays for the duration of the sound. This results in the ever-changing sound of a windchime; it gets “richer and richer.”

I’ll upload the pics of the graphs to our photobucket very very soon, since I can’t figure out how to post them here…


One Comment leave one →
  1. September 13, 2009 5:52 pm

    You should link the images, otherwise it is difficult to understand what you are talking about.


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