Sound wave -- positive and negative frequency?

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Sound waves can be analyzed using the Fourier transform, which reveals their frequency components. Each sound wave, including those produced by speech or music, can be represented in terms of positive and negative frequencies due to the mathematical nature of the Fourier transform. This duality is primarily a mathematical artifact rather than a physical property of sound waves. The discussion highlights the relationship between sine waves and sound waves, confirming that the principles of Fourier analysis apply to both. Understanding this concept is essential for analyzing sound in various applications.
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does ever sound wave have a positive and negative frequency?
 
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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
Hw12b.jpg
 
I know it is right for a sinwave, or you saying it is the same for sound wave? like someone talking or singing?
 
Thread 'Colors in a plasma globe'

Thread 'Colors in a plasma globe'

I have a common plasma globe with blue streamers and orange pads at both ends. The orange light is emitted by neon and the blue light is presumably emitted by argon and xenon. Why are the streamers blue while the pads at both ends are orange? A plasma globe's electric field is strong near the central electrode, decreasing with distance, so I would not expect the orange color at both ends.
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