[sdiy] Fourier Analysis Question

[Richard Wentk]

You can, but FFTs are almost useless for analysing fast attacks, because the window size isn't small enough to capture the partial movement within the attack. 

Also, pianos - like most instruments - include inharmonic partials. The whole point of a piano is the phasing and movement you can hear if you hold down a chord, and that's created by deliberate detuning of the strings. 

This means no single waveform is exactly identical to any other cycle. 

Discrete stepped timbre-frame synthesis won't capture that.

You can use stepped timbres for conventional synthetic wavetable synthesis, but there's no advantage to using FFTs instead of ROM wavetables unless you're recalculating them dynamically. And if you're doing that you may as well build a system with N DCOs controlled by partial track information that can be calculated, interpolated and modulated with a decent refresh rate of - say a few kHz.

For that approach you use FFT analysis to create a database of partial sets that varies with time, frequency and velocity, and then interpolate between partial sets dynamically as the note evolves. 

I think the Hartmann Neuron used to do something like this. 

R

On 17 Dec 2010, at 15:09, Tom Wiltshire wrote:

> </background>
> 
> So the question is this:
> 
> Can you break one long fourier analysis result into an approximate copy based on a series of lower resolution fourier analyses without going back to the time domain?
> 
> Any clues or comments appreciated.
> Thanks,
> Tom
> 
> 
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