[sharing] that phase vocoder


    Mar 05 2008 | 9:54 pm
    This patch reflects the conclusions of a search for a proper sounding phase vocoder. It's built using standard max objects and includes convolution and a spectral filter a la forbidden planet. Therefor the thing is called pv-c-fp and can be found at the bottom of the page:
    www.jvkr.nl/shelves
    It has some great features that make it fun to play with. Enjoy it. If the patch don't work, there's a collective too.
    _
    johan

    • Mar 06 2008 | 2:53 am
      Looks like you have some other useful tools there too. Index is gonna come in handy for me. Thanks for sharing.
    • Mar 06 2008 | 5:51 am
      Quote: jvkr wrote on Wed, 05 March 2008 13:54
      ----------------------------------------------------
      > It has some great features that make it fun to play with. Enjoy it.
      I'm enjoying it. It's great, thank you! I've been meaning to learn more about phase vocoding. This will help.
    • Mar 06 2008 | 9:44 pm
      > I'm enjoying it. It's great, thank you! I've been meaning to learn more about phase vocoding. This will help.
      From here it's possible to do some useful additions, like cepstrum analysis in order to acquire more insight into e.g. noisyness of the signal. That would lead to more meaningfull ways of resynthesis. I'm attempting such things right now.
      Good to hear it's working.
      _
      johan
    • Mar 08 2008 | 11:02 am
      This is a nice patch. Open some doors for experimentation. I'm looking forward to see the new additions.
      Thanks for sharing.
    • Mar 13 2008 | 5:54 pm
      Concerning the filer. Today I tried to make it "usable".
      I mean, it would be great to have it in log mode (like the spectrogram in log mode).
      Here we only have 20 sliders to cover 1000 Hz, and 200+ sliders to cover the rest. The problem is that I'm more interested in the first sliders than the others...
      I first thought I would make an interface for it.
      A multislider with bigger sliders than others...
      But I think it's more an internal problem.
      Maybe there's no way to change it, I don't know.
    • Mar 13 2008 | 10:23 pm
      Quote: Bertrand Fraysse wrote on Thu, 13 March 2008 18:54
      ----------------------------------------------------
      > Concerning the filer. Today I tried to make it "usable".
      >
      > I mean, it would be great to have it in log mode (like the spectrogram in log mode).
      >
      > Here we only have 20 sliders to cover 1000 Hz, and 200+ sliders to cover the rest. The problem is that I'm more interested in the first sliders than the others...
      >
      > I first thought I would make an interface for it.
      > A multislider with bigger sliders than others...
      > But I think it's more an internal problem.
      >
      > Maybe there's no way to change it, I don't know.
      ----------------------------------------------------
      This is an interesting problem. One approach I tried is to use a filtergraph. In log display on the horizontal axis, it is possible to define a evenly spaced curve that can be queried in terms of bins. This approach doesn't allow though to select single bins on the lower bin side, although it works on the higher bin side. Maybe a combination of the two would be something.
      It is a problem inherent to Fourier analysis: lots of definition where you don't hear it (in terms of individual bins) and a few where they matter most. To my understanding, the wavelet transform fixes this to some degree.
      _
      johan
    • Mar 14 2008 | 1:31 pm
      I tried to put a [log~] between the FFT Bin Index and the sample index of [index~].
      And it works very well !
      -------------------------- PFFT Patch --------------------------
      SAVE AS "log_fft_filter.pat"
      -------------------------- Main Patch --------------------------
      -----------------------------------------------------------------
      [*~ 0.0625] in the PFFT patch is here to reduce the number of sliders (but the precision too).
      The log factor can be tweaked to best feat the spectrogram but I don't know the spectrogram log coefficient.
      If you have any idea...
      Have fun.
    • Mar 14 2008 | 10:10 pm
      > And it works very well !
      Good idea. I modified it slightly, choosing a pow function (output values are easier to control) and incorporated it into the pv-c-fp patch: jvkr.nl/shelves.
      _
      johan