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Re: 3D Audio -improving HRTF filtering

Hi  piotr,


thanks you very much for the info ..
>"You should zero-pad the signal to the 1024+128 to avoid time aliasing."

I wasn't doing this ...

now its working ..





On 4/5/06, Piotr Majdak <piotr@xxxxxxxxxx> wrote:
> Hi Sherin,
>
> sherin tech wrote:
>
> > the steps involved in my new implemantation are ...
> >
> > 1) take 1024 number of samples.
> > 2) Window those 1024 samples. (for this I am now using kaiser window of beta=16)
> > 3) Take 1024 point FFT the input
>
> You should zero-pad the signal to the 1024+128 to avoid time aliasing.
>
> > 4) Zero pad the 128 point HRTF filter to make it 1024 point.
>
> Then you must zero-pad the HRTF to 1024+128.
>
> > 5) Take 1024 FFT of HRTF Left ans Right data.
> > 6) Multiply the spectrum in frequency domain.
> > 7) Take 1024 point IFFT of the resultant spectrum.
> > 8) Do a 75 % overlap and add.
>
> The perfect reconstruction is given only if the resynthesis window is dual to
> the analysis window. I don't know it for the kaiser window, but you can try to
> change the resynthesis overlap factor in such a way, that the square sum of the
> kaiser windows is constant. This should give you an almost perfect resynthesis,
> I think...
>
> br, Piotr Majdak
>
>
> --
> Piotr Majdak
> Institut für Schallforschung
> Österreichische Akademie der Wissenschaften
> Reichsratsstr. 17
> A-1010 Wien
> Tel.: +43-1-4277-29511
> Fax: +43-1-4277-9296
> E-Mail: piotr@xxxxxxxxxx
> WWW: http://www.kfs.oeaw.ac.at
>
>
>