reply to post by CLPrime
Now, I know I disregarded the 7.4 Hz, but....
Before I do anything else, I want to take that frequency to a slightly greater precision. The period found was 0.135 seconds (that's about as precise
as we can get with that, from the provided graph alone). This gives a frequency of 7.40741 Hz. I know that teacher in high school who tried so hard to
pound the concept of significant digits into your heads would kick me in the knees for taking that past 7.407, but they're staying. I'm a rebel, I
know.
Also, if this actually does exist as a distinct frequency of the roaring sound, then it's probably the fundamental frequency, with all other
frequencies arising from it. This is particularly important.
As I said, the peak frequencies of the ringing sound were 948, 1008, 1185 and 1304 Hz.
After some more math, we find that the greatest common (non-integer) factor of these is ~59.27. That means, 59.27 is the greatest possible value of a
potential fundamental frequency of the ringing sound. Of course, it's possible that the ringing doesn't have a fundamental frequency, but, if it
does, this would either be it or some integer multiple of it...and the fact that this number even exists is significant.
So, if 59.27 is the fundamental frequency:
948 Hz is the 16th resonance
1008 Hz is the 17th resonance
1185 Hz is the 20th resonance
1304 Hz is the 22nd resonance
But, 59.27 still may not be the fundamental frequency. It could be some integer division of 59.27.
So, look what happens when you divide 59.27 by 8. You get 7.40875.
In that case:
948 Hz is the 128th resonance
1008 Hz is the 136th resonance
1185 Hz is the 160th resonance
1304 Hz is the 176th resonance
Also, for the roaring sound:
134 Hz is the 18th resonance
155 Hz is the 21st resonance
148-147 Hz is the 20th resonance
137-130 Hz is centered on the 18th resonance
In short...
- the fundamental frequency of the ringing could be 7.40875
- the fundamental frequency of the roaring could be 7.40741
And this is very close to the Earth's fundamental Schumann frequency (~7.44 Hz).