posted on Dec, 21 2011 @ 10:32 PM
I just did a frequency analysis of the entire file. Here's what I found:
First of all, there is absolutely no peak frequency at 7.4 Hz. Whatever we think we see in the 0.6-second analysis posted a couple pages ago, it's
not a peak frequency at 7.4 Hz. There is nothing of the sort in either the original file or the cleaned version (I analyzed both, of course, just in
case the "cleaning" of the second one happened to change anything...which it never).
The roaring sound is a wandering range of frequencies. At first, it hangs between 0 and 200 Hz, and then it expands slightly to between 0 and 250 Hz,
before expanding once more to include up to 300 Hz.
So, in general, over the course of the entire file, the sound is a collection of frequencies between 0 and 300 Hz.
Now, the peaks in that range... there are several (though they occur one at a time, so it's a relatively clean sound, it just jumps around a bit).
In the first half of the file, the first peak is at 134, and the second is at 155 Hz.
In the second half, for the time between the loud wind sound and the start of the ringing, the peak wanders from 148 to 147 Hz before vanishing.
Then, the ringing starts, which I'll get to in a sec.
Once the ringing stops, the sound gets louder up to the end, and this is a single peak which pans down from 137 to 130 Hz.
Now, the ringing. It's actually a simultaneous combination of 3, sometimes 4, peak frequencies. The 3 regular peaks are at 1008, 1185, and 1304 Hz.
The 4th peak frequency, which is intermittent, is at 948 Hz.
So, there you go. Frequency analysis. What it might mean, I have no idea, but there it is.