butterworth problem with plot ??

    May 30 2017 | 6:03 pm
    I don't understantd what's happening at the low end, below 90 Hz in order 2.

    • May 30 2017 | 7:16 pm
      more gain change by phase than by actual filter damping?
    • May 31 2017 | 8:04 pm
      Strange knee !!
    • Jun 02 2017 | 9:48 am
      In the help patch, from [filterdesign], when setting highpass with butterworth in range 2 (and 3), i don't understand the low end, a big slope below 40 hz, with a big break, a big knee, ???
      i have a probleme with my first plot, not the good range i think...
    • Jun 03 2017 | 11:10 am
      that is just what the order 2 and 3 coefficients are capable of. order 2 (biquad) clean to -72 dB is pretty good. order 3 to -108 db very good. i mean, i cannot hear that quietly at that frequency. can you?
      choosing what settings you want is all about the task at hand.
    • Jun 12 2017 | 5:45 pm
      The "big knee" you see is simply due to the resolution of the display. When the plot~ object is doing a logarithmic display the first points are very far apart while the later points are very compressed together.