Audio fun with Fourier transform

[Xzu Rukneg]

Hi there.
Note: I'm not developer at all, now I'm only a musician!
(And I use google translate to improve my english!)

But, before, I've worked with IRM http://en.wikipedia.org/wiki/Magnetic_resonance_imaging.
With this technology, we got a signal with an antenna, and "put" it in Fourier transform http://en.wikipedia.org/wiki/Fourier_transform.
Then, with a 2d projection, we obtains an image.

Fourier transform can extract all the harmonics components of a signal (maybe it needs other mathematics tools, I'm just a user!! ).

What I would like to do is to do that with any audio signal.
I would like to obtains all the perfect sinusoids and the plays with their gain or just select one of them (and mute the others).
That will be very fun!

Does it already exist?

[varpa]

Fourier analysis is the basis of many audio plugins such as equalizers, multiband compressors, or "exciters" which amplify harmonics as you would like to do. So the answer is a large number of plugins which you already know about use Fourier analysis.

[Xzu Rukneg]

Fourier analysis is the basis of many audio plugins

Sure.
But can I get direcly the composition of a spectre, harmonics one by one?

[Xzu Rukneg]

For example:

A- I make a perfect sinusoidal wave: the plug give me only one result

B- another Casi-perfect one: the plug give me the fundamental and the harmonics. Now I can shut the harmonics to transform the signal into perfect wave.

C- an audio signal: the plug give me a lot of results, the fundamental can be guessed by there big amplitudes, i can transform the signal by amplification of harmonics, or by muting some big component.

An Eq can't do this (event if that looks like).
I'm looking to a tool that don't show the spectrum analysis by a scale (like EQ) but by composition of perfect sinusoidal wave in the signal.
And i would like to modify their amplitude.

Does this exist?
I don't found it.

[StudioDave]

Greetings !

I believe that Csound has a set of audio functions based on the phase vocoder that will let you do just what you want.

You should consider learning how to use environments such as Csound, SuperCollider3, and Pure Data :

http://www.csounds.com/

http://puredata.info/

http://supercollider.sourceforge.net/

Look into the manuals of those environments for more information.

You might also consider reading The Audio Programming Book and/or Charles Dodge's Computer Music :

http://mitpress.mit.edu/books/audio-programming-book

http://www.amazon.com/Computer-Music-Sy ... 0028646827

Best regards,

dp

[Xzu Rukneg]

Thanks for your response.

I'll look Csound.

Supercollider and pure data, well, they afraid me!

Pure data can do some thing like this?

Hmm, I guess there is no easy tool like this:



But I've try, some times what you're looking for is just ready and near you.

[SeeLook]

http://miracle.otago.ac.nz/tartini/

Try this Excellent application to analyse pitch of sound, its harmonics and other aspects.
You can really look into sound.

[Xzu Rukneg]

Thank you SeeLook for the answer!

Harmonic structure of a note describing timbre

I think it's what I'm looking for, but I don't know if I can change this structure (amplitude of each harmonics, or add some).