# Fourier transform

Discussion in 'Physics' started by gils, Oct 9, 2012.

1. ### gils Thread Starter New Member

Oct 9, 2012
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0
hello everybody, does anybody knows if the humen ear hears sound and in the same time we transmit the inverse sound (fft and ifft) the human brain interpret it to a silence???

2. ### MrChips Moderator

Oct 2, 2009
12,652
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10-9? Come again? I can't hear what you are saying.

Last edited: Oct 9, 2012
3. ### gils Thread Starter New Member

Oct 9, 2012
2
0
it's a bit hard to explain, but if human brain hear to opposite sounds (with inverse fourier transformation) in parallel it's sounds like silence

4. ### MrChips Moderator

Oct 2, 2009
12,652
3,461
I think you are off track. The human ear responds to a time variant signal.
The fft and ifft does not create any kind of inverse. In fact, the fft followed by the ifft would produce the same signal and sound.
(Incidentally, the cochlea performs its own fourier transform, i.e. it responds to frequencies.)

5. ### SPQR Member

Nov 4, 2011
379
48
Nope.
The human ear sends serial signals (amplitude and frequency) from the cochlear hair/nerve bundles to the auditory cortex. The auditory cortex processes those signals into "stuff" that the rest of the cortex recognizes.

The presence of two ears allows the cortex to spatially analyze the direction of sound.

I suppose that and FFT is an analog of the signal processing done in the cortex (a serial stream translated into a "cortical pattern" (the FFT graph).

But remember that the human ear came about a few million years before the FFT - so mathematical and physical science is far behind human biology.

And in terms of the "reverse FFT", no, there is no "cortical auditory pattern" that is shoved out our mouth.

6. ### MrChips Moderator

Oct 2, 2009
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3,461
Monsieur Fourier lived during the 18th century. He only formulated something that existed since the beginning of time.

7. ### THE_RB AAC Fanatic!

Feb 11, 2008
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Sound cancellation only works reasonably well at low frequencies at a relatively fixed single frequency. With higher frequencies your ears are 0.X waveform apart so you might cancel it on one ear but not on the other, also some of the sound you hear comes from bone conduction, room reflections etc which is at a different phase relationship too.

That whole concept of a "box that makes reverse sound and makes everything silent" is completely SciFi.