[PD] I wanna sing like Paris

[Roman Haefeli]

On Tue, 2010-08-17 at 13:59 +0200, Matteo Sisti Sette wrote:
> On 08/17/2010 01:39 PM, Roman Haefeli wrote:
> > On Tue, 2010-08-17 at 12:59 +0200, martin brinkmann wrote:
> >
> >> i will try this when i have found a way to extract
> >> single-cycle waves from audio input in pd...
> >
> > Not yet tried it myself, but what about writing live input to a table
> > (for instance with [tabwrite~]) in order to have access to the audio
> > data with message based objects? With those it should be fairly easy to
> > the detect the exact position of a zero crossing. For finding a single
> > cycle, it would be sufficient to find a positive crossing - for
> > instance-  and from there find the next one, so you have the exact end
> > points of one single cycle.
> >
> 
> How would you look for zero crossings? With message based objects such 
> as [until], a counter, [tabread] and comparing to zero?
> Is that feasible?
> 
> (sorry for hijacking the discussion, I am curious about that)

yeah, actually that's what I thought about. I guess, one would not
compare to zero, but compare to the previous sample and check whether
the sign has changed. One could even perform linear (or even polynomial
interpolation) to find the subsample accurate location of the crossing. 

Roman