HISE Logo Forum
    • Categories
    • Register
    • Login

    Oversampling

    Scheduled Pinned Locked Moved General Questions
    7 Posts 3 Posters 471 Views
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • C
      clumsybear
      last edited by

      I did some tests to see what oversampling method would get the best results.
      So I send a sine wave through the ShapeFX Module with 1x & 16x Oversampling. The results were as expected.

      But how can I get rid of the aliasing in the low end? Is there a way to oversample 32x?

      Screenshot 2019-09-12 at 18.33.51.png

      I have to be honest here, I understand the basic concept of oversampling but I'm no DSP guru.

      FortuneF 1 Reply Last reply Reply Quote 0
      • FortuneF
        Fortune @clumsybear
        last edited by

        @clumsybear What do you mean with low end aliasing? You can observe aliasing in only high frequencies, because it causes high frequency distortion.

        I suggest that do not analyse the that in Hise with this analyser. Export your plugin and select different oversampling modes.

        In Shaper fx, oversampling is up to x16. But in scriptnode, I think you can use much more than that.

        1 Reply Last reply Reply Quote 0
        • C
          clumsybear
          last edited by

          So you're saying the noise in the low end is not aliasing? @Fortune

          I did the same with plugin doctor, but the difference between 1x and 16x is very marginal. I can't really see it in the harmonic analysis

          1x:
          Screenshot 2019-09-12 at 18.57.37.png

          16x:
          Screenshot 2019-09-12 at 18.57.50.png

          1 Reply Last reply Reply Quote 0
          • FortuneF
            Fortune
            last edited by Fortune

            As you can see, between 0 and 500 Hz is very similar. There is no such thing like low aliasing. The noise is harmonic distortion.

            Did you give saturation or increased the gain of the Shape fx? When you increase, you will see the difference. :)

            1 Reply Last reply Reply Quote 0
            • C
              clumsybear
              last edited by

              I did not increase the gain on the the screenshots above It's just running through the shape fx. But I tried it right now.
              With the Gain at +15dB there is still no difference to see between 1x and 16x Oversampling.

              @Fortune said in Oversampling:

              As you can see, between 0 and 500 Hz is very similar.

              I feel like there is no difference at all, even above 500Hz. But, maybe that's why I'm no DSP Guru, I have no clue :D

              FortuneF 1 Reply Last reply Reply Quote 0
              • FortuneF
                Fortune @clumsybear
                last edited by Fortune

                @clumsybear I can see the difference with 6 dB.

                I suggest that: make a shape fx plugin with a gain knob and OS selection, export it and open it in Plugin Doctor ;)

                By the way are you sure that you are changing the OS in shape fx with the combobox that you add? :)

                1 Reply Last reply Reply Quote 0
                • Christoph HartC
                  Christoph Hart
                  last edited by

                  The aliasing will be more evident for higher frequencies or more harmonic content - if you use a saw, you'll see the "fold-back" of the harmonics into the audible spectrum.

                  I'd say forget about the low frequency noise, that's most likely some rounding error in the FFT (it's lurking around at -100dB so it's far from perceivable).

                  1 Reply Last reply Reply Quote 2
                  • First post
                    Last post

                  22

                  Online

                  1.7k

                  Users

                  11.8k

                  Topics

                  103.1k

                  Posts