pfft~ or delay~ bug or me


    Mar 06 2007 | 5:30 am
    Ok just finished installing the latest and greatest Cycling 74 programs. If one were to put a signal through a pfft~ of size 512 and then delay~ the same signal by 512~ shouldn't one expect silence from the subtraction of the two resultant signals. I get no sound for 448 delay~
    Windows Xp AMD Athlong 64 Dual Core Processor 4800+ 2.00GB of RAM
    here is the example patch
    here is the pfft patch "pfft_test"

    • Mar 06 2007 | 9:41 am
      On 06 Mar 2007, at 06:30, Tyler Nitsch wrote:
      > > Ok just finished installing the latest and greatest Cycling 74 > programs. If one were to put a signal through a pfft~ of size 512 > and then delay~ the same signal by 512~ shouldn't one expect > silence from the subtraction of the two resultant signals. I get > no sound for 448 delay~
      AFAIK the actual delay caused by pfft is fft-size minus signal vector size. i guess your sigvs is set to 64. try patch below.
      what makes me wonder though, is that i don't get complete silence using a blackman window. hanning and rectangle is fine. -volker.
    • Mar 07 2007 | 12:10 am
      I would of thought that the signal vector size would imply the same delay on both the delay object and the pfft~. Not sure why the sig vector needs to be accounted for with the delay? Thanks for the solution though!!
    • Mar 08 2007 | 1:23 pm
      Tyler Nitsch schrieb: > I would of thought that the signal vector size would imply the same > delay on both the delay object and the pfft~. Not sure why the sig > vector needs to be accounted for with the delay?
      imagine you have the same vector size as fft size, you'd calculate the whole within one frame and thus be ready at the same time. It's just the fastest way to do it... (and that's what we want... ;-)
      Stefan
      -- Stefan Tiedje------------x------- --_____-----------|-------------- --(_|_ ----|-----|-----()------- -- _|_)----|-----()-------------- ----------()--------www.ccmix.com
    • Mar 15 2007 | 6:23 am
      Blackman windowing doesn't work properly for pfft.
    • Mar 15 2007 | 6:32 am
      let me tone down the frustration in that last post haha
      "blackman windowing appears not to be working properly"
      and thanks Volker and Stefan for straightening me out over the delay~ object.