Sound wave -- positive and negative frequency?

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btb4198
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does ever sound wave have a positive and negative frequency?
 

Discussion

btb4198 said:
does ever sound wave have a positive and negative frequency?
Sure. Are you familiar with the Fourier transform?
 
berkeman said:
Sure. Are you familiar with the Fourier transform?
yes, I am. why do you ask ?
 
btb4198 said:
yes, I am. why do you ask ?
Because when you take the Fourier transform of a sine wave, you get a spectrum plot like this:

http://fweb.wallawalla.edu/class-wiki/upload/f/fa/Hw12b.jpg
Plot titled CFT of magnitude against frequency from -2 to 2, showing two sharp spikes of height about 1800 at frequencies of -1 and 1, with small side lobes near each spike and near zero elsewhere.
 
I know it is right for a sinwave, or you saying it is the same for sound wave? like someone talking or singing?
 

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