[Clam-devel] Spectral Analysis/Synthesis

[Karsten Krispin]

Am Mittwoch, 13. Februar 2008 18:17:11 schrieb Xavier Amatriain:
> Hope it helps. In any case I recommend that you feed to the process a
> pure sinusoid, or better still a sweep. This will give you an exact idea
> of what is going on in the process and you might be able to post a
> screenshot :-)

My Synth is now ready to oscillate what the processings are producing. 
So, here we go. (Screenshot is in atachment)

There are two Item. One is a sinus-producer, the other one is a filter which 
currently just does the Analysis/Synthesis and no transform.

Each drawn wave represent 512 samples. So actually it just draws an 
CLAM::Audio with size of 512, which has been pushed out by each item. 

What I corrected in the anal/synth-part with buffers, was creating a temporary 
buffer of WindowSize and copied the actualy buffer (512 samples), which is to 
analyse/synthesize, in the middle of the temporary buffer (like Synthesis is 
reconstructing the Spectrum to Audio).

In that example it's WindowSize is 2048 and FrameSize is 512.

Everything is fine now (the Sinus is not disorted anymore), except the fact 
that in each audio buffer the amplitude in the middle of the buffer is a way 
smaller than at the edges. This could be pretty good seen in the screenshot. 
So this results in an extra sinus wave... the same like a (acoustical) beat, 
obviously.

Perhaps you know the sympton of that and could tell me something about it.
I guess this has something todo with windowing, but I've got no clue. 
Window-Size and Window-Type are the same in Anal and Synth. 

Thanks and greetings from sunny but cold lower rhine,

Karsten
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