[PD] a phase vocoder pitch shifter harmonizer in real time

Charles Henry czhenry at gmail.com
Tue Jan 10 17:08:51 CET 2012

On 1/10/12, Alexandre Torres Porres <porres at gmail.com> wrote:
> sorry, what dont you get?

I guess the shifter+mixer makes sense for the harmonizer--I just don't
see why it's running when I just want to hear the pitch shifting
effect by itself.  Is that just a mistake?

This is unrelated, but when I use [openpanel] under linux, it only
lets me select *.pd files.  I guess I'll mess with readsf~ by passing
messages so I can try it out with some sound files.

> you're supposed to first hear the beatings and then the shift up anyway.
> well, let me try with some oscilattors myself, that should be fun
> see ya
> 2012/1/9 Charles Henry <czhenry at gmail.com>
>> Hey Alex
>> I'm just trying this out.  I didn't have a sound file I particularly
>> wanted to try, so I just plugged in an osc~, and what I found on the
>> output:  a mixture of the original tone with the shifted one.
>> So, the shifted tone was clearly audible, but as I shifted the
>> frequency, I could hear first the beating of the tones then two tones.
>> And upon reading into the patch, that's clearly what you're doing in a
>> subpatch, but I don't get why?
>> Chuck
>> On 1/9/12, Alexandre Torres Porres <porres at gmail.com> wrote:
>> > Hi Folks,
>> >
>> > working with these phase vocoder stuff, I thought I'd try and do a
>> > simple
>> > shifter/harmonizer with it once and for all. The phase vocoder shifter I
>> > found in pdmtl doesn't work as a harmonizer, and the latency was pretty
>> > high and not constant, so I did this. It's all as a Vanila abstraction!
>> >
>> > I have 2 short buffers (arrays) and do crossfade between them, I got
>> > some
>> > phase issues trying out and building it, but they now seem reasonably
>> fine.
>> >
>> > I just did this, so I should work more on it to make it more stable and
>> > robust. I'm sure there are some bugs around, and it's still very dirty
>> and
>> > needs code cleaning. Maybe I should try and implement it with delay
>> > lines
>> > as in pdmtl, hmmm, I guess it'd be better, right? Hmm... Later on when I
>> > have the time...
>> >
>> > Anyway, this goes back to the Pd Shifting thread I started here a while
>> > ago. I really like the quality of the phase vocoder. Somehow I don't get
>> > interested so much on other techniques and such. Yes, I assume there are
>> > some advantages out there, so what exactly would I be missing?
>> >
>> > Well, Check this thing I did out, see what you think, let's talk some
>> more
>> > about pitch shifting....
>> >
>> > get it here: http://sites.google.com/site/porres/pvoc-shifter.zip
>> >
>> > I wish to officially release it along with some other tools I'm building
>> > for my PhD, soon to be over...
>> >
>> > by the way, I see this object is finally available
>> > http://www.katjaas.nl/pitchshift/pitchshift.html need to try it out.
>> >
>> > cheers alex
>> >

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