[PD] OT: Windowing

[J. Scott Hildebrand]

i've done a TINY bit of granular synthesis in csound, and i don't remember
doing any FFTs or windowing. i don't remember very well how it all worked
though. i'm pretty familiar with overlap'n'add because i've had to use
that for convolution externals. i do it in 'externals' though and not in
pd. if i saw a patch that does all the shit that i do in my convolution
external it would make my head spin.


On Thu, 3 Jul 2003, matthew jones wrote:

> Hi,
> quick OT question for any of the granular synthesis brains out there...
> I want to reconstruct a signal from multiple overlapped segments.  To use an
> overlapp-add method that perfectly reconstructs the original waveform I
> would need to window the segments... now thats fine as long as the overlap
> amount is less than 50 percent.  I can use a Hanning window on the
> overlapping parts and sum them..... Hanning windows satisfy the sum to unity
> criterion.  however, when the overlap is more than 50%, the half-Hanning
> windows applied to the start and end of the segments windows begin to
> overlap.... see this link:
> http://www.loopit.org/images/overlap.jpg
>
> Now multiplying the overlapped half-Hanning windows together creates a new
> window function for the segments that suddenly does not satisfy the
> 'sum-to-unity' criterion....
> The question is (if anybody can is at all interested):- WHAT window function
> should be used given ANY arbitrary overlap amount???
>
> Any answers would really help me, though I'd be surprised if this gets a
> response.... ;)
> sorry 2 b so off topic, though for me it's pd related anyway(!). cheers
>
> matt
>
> -=-=-=-=-=-=-=-=-=-=-=-=-
> http://www.loopit.org/
> -=-=-=-=-=-=-=-=-=-=-=-=-
>
>
> _______________________________________________
> PD-list mailing list
> PD-list at iem.at
> http://iem.at/cgi-bin/mailman/listinfo/pd-list
>




--------------------------------------------------------------------

	"640K ought to be enough for anybody." -- Bill Gates, 1981

--------------------------------------------------------------------