does ever sound wave have a positive and negative frequency?
Sure. Are you familiar with the Fourier transform?
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:
I know it is right for a sinwave, or you saying it is the same for sound wave? like someone talking or singing?
Yes, I believe so. It's mainly a mathematical artifact of the way the FT is calculated. Do you have some particular thing in mind?
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