[PD] normalizing hann window

[Miller Puckette]

Hi all -

I believe the general formula for Hann is to divide by 
(3/8 * overlap * window size).

this assumes that the inout and output are both Hann windowed, therefore
you're really dindowing by the square of the Hann window whose average
over N points is 3/8.

cheers
Miller

On Fri, Oct 12, 2012 at 05:44:20PM -0500, Charles Henry wrote:
> On Fri, Oct 12, 2012 at 4:59 PM, Alexandre Torres Porres
> <porres at gmail.com> wrote:
> > hi there, in pd's examples, we need to divide by (3/2 * window size) in a 4
> > overlap on a hann window.
> >
> > what about other overlaps, what is the normalizing factor?
> >
> > and how about other windows?
> >
> > I looked for this info on books and google and stuff, found nothing.
> >
> > Engineers, please help.
> >
> > thanks
> > Alex
> 
> I'm not exactly sure why it's used either.  If you were using a
> overlap of 2 and used hann windows that cover each block, you would
> get back the exact signal after applying overlap-and-add with no
> additional normalization.
> 
> So, for the same scheme and overlap 4, it stands to reason that you'd
> only divide by 2 and recover the original signal as well.
> 
> What's the window size like relative to the block size?  same/different?
> 
> Some other engineer--please help.
> 
> Chuck
> 
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