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    Distortion Whiz required...

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    • griffinboyG
      griffinboy @DanH
      last edited by griffinboy

      @DanH
      Yes use a snex node.
      I don't recommend using the shapeFX, it's not precice for designing this type of effect, not to mention that you want to use scriptnode anyway, because more goes into distortion than just wave shapers.
      You have filters, multiple shapers with different gain stages, and logic to change the curve depending on the input gain.

      Edit* you say you want to use the node to 'simply' boost the fundamental, but to choose specific harmonics to boost, you'll have to use either trial and error, or Chebyshev polynomials.
      Look into Chebyshev polynomial waveshaping.

      1 Reply Last reply Reply Quote 0
      • griffinboyG
        griffinboy @DanH
        last edited by griffinboy

        @DanH

        I might have solved this if you are still looking for a solution.
        The first harmonic is the sine wave, the second is generated by my algorithm.

        This algorithm only boosts the first harmonic, no matter how high the gain is.

        16afa3e1-3e5d-40d1-bf52-3d5367cf8e32-image.png

        Let me know if you want the algorithm, if this is what you meant when you made the post.

        Edit: if you were in fact referring to the fundamental needing boosting, rather than the first harmonic needing boosting, then that's even easier and I can solve that for you in a simple step.

        DanHD 1 Reply Last reply Reply Quote 0
        • DanHD
          DanH @griffinboy
          last edited by

          @griffinboy ah amazing! Yes mainly the fundamental - but a small boost to the first harmonic is also really useful!

          DHPlugins / DC Breaks | Artist / Producer / DJ / Developer
          https://dhplugins.com/ | https://dcbreaks.com/
          London, UK

          griffinboyG 1 Reply Last reply Reply Quote 0
          • griffinboyG
            griffinboy @DanH
            last edited by griffinboy

            @DanH

            To make the fundamental louder, you simply need to mix the original signal with the saturated signal, that way you can control how loud the original fundamental is, compared to the generated saturation harmonics.
            Having less distortion mixed in, means that the fundamental, by comparison, is louder.

            Now, for the first harmonic, here is the snex code.
            You will need to create a snex shaper node, create a new file inside the snex node and call it firstorder, then paste in the code at the bottom of this post.

            694d901a-a34a-44eb-875e-6e5ba6cf9087-image.png

            You will also want to place this filter afterwards, it gets rid of subsonic frequencies.
            Create a wet / dry matrix (there is a template node for this) and a simple gain. Gain staging will allow you to control the loudness of the harmonic.

            Code:

            template <int NV> struct firstorder
            {
                SNEX_NODE(firstorder);
                
                // USE VERY HIGH INPUT AND OUTPUT GAIN (390 input gain)
                    // Generates first order harmonic only
                
                // Front end variables
                    float drive = 2.0f;    // Controls saturation
                    float mix = 0.5f;      // Dry/Wet Mix
                    float bias = 0.6f;     // Dynamic bias (if we need it)
                    float tone = 0.7f;     // Tone control for filtering (if we need it)
                    
                    float outGain = 0.7f; // (Control the volume of the whole signal after processing)
                    float preGain = 390.0f; // (an pre-gain for gain staging)
                
                        // Operating point and tube model parameters
                        float E = 250.0f; // Anode voltage in Volts
                        float Rp = 100000.0f; // Plate resistance in Ohms
                        float Rk = 1000.0f; // Cathode resistance in Ohms
                        float Ck = 10e-6f; // Cathode capacitance in Farads
                    
                        // Quadric surface model coefficients
                        float kp = 1.014e-5f;  // Coefficient for Vpk
                        float kp2 = 5.498e-8f; // Coefficient for Vpk squared
                        float kpg = 1.076e-5f; // Cross-product coefficient for Vgk * Vpk
                    
                        // Internal state variables
                        float Vk0 = 0.0f;  // Initial cathode voltage
                        float Vp0 = 0.0f;  // Initial plate voltage
                
                    float getSample(float input)
                    {
                         // Apply pre-gain to the input
                        float Vgk = input * preGain;
                
                        // Compute plate-to-cathode voltage
                        float Vpk = E - Vgk;
                
                        // Compute the current through the plate using the quadric surface model
                        float ip = kp2 * Vpk * Vpk + kpg * Vgk * Vpk + kp * Vpk;
                
                        // Apply the output gain
                        float output = ip * outGain;
                
                        return output;
                    }
                
                    // Process each sample of the data
                    template <typename T> void process(T& data)
                    {
                        for (auto ch : data)
                        {
                            for (auto& s : data.toChannelData(ch))
                            {
                                s = getSample(s);
                            }
                        }
                    }
                
                    // Process each sample for a single frame of data
                    template <typename T> void processFrame(T& data)
                    {
                        for (auto& s : data)
                            s = getSample(s);
                    }
                
                    void reset()
                    {
                 
                    }
                
                    // Set up Stereo processing 
                    static const int NUM_CHANNELS = 2;
                    // Get the project sampleRate
                    double sr = 0.0;
                    void prepare(PrepareSpecs ps)
                    {
                        sr = ps.sampleRate;
                    }
                    
                    
                    void recomputeConstants()
                     {
                         // Calculate constants based on initial conditions
                         float k1 = kpg / (2.0f * kp2) + Rp / Rk + 1.0f;
                         float k2 = k1 * (kp / kp2 + 2.0f * E) * kp2;
                         float k3 = Rk * k2 + 1.0f;
                         
                         Vk0 = (k3 - Math.sqrt(k3 * k3 - 1.0f)) / (2.0f * Rk * k1 * k1 *kp2);
                         
                         Vp0 = E - Rp / Rk * Vk0;
                     }
                    
                    
                    void prepareToPlay(double sampleRate)
                       {
                           recomputeConstants();
                       }
                       
                      
                
                
                    void setExternalData(const ExternalData& d, int index)
                    {
                        // Optional: External data setting
                    }
                
            
                
            
            
            
                
                // Process the MIDI events here
                void handleHiseEvent(HiseEvent& e)
                {
                    
                }
                
                
                
                // Set the parameters here
                template <int P> void setParameter(double v)
                {
                    
                }
            };
            
            
            DanHD 1 Reply Last reply Reply Quote 1
            • DanHD
              DanH @griffinboy
              last edited by

              @griffinboy Thank you! Will give this a try asap :)

              DHPlugins / DC Breaks | Artist / Producer / DJ / Developer
              https://dhplugins.com/ | https://dcbreaks.com/
              London, UK

              griffinboyG 1 Reply Last reply Reply Quote 1
              • griffinboyG
                griffinboy @DanH
                last edited by griffinboy

                @DanH
                If there are any problems let me know.
                Copying and pasting snex can be a little weird sometimes... Surprise errors and such

                Edit*
                Realised that this code might produce a silent output.
                If you do want it fixed, I can do that for you just let me know.
                I tried to simplify it a bit but I think removing the controls impacted the functionality

                DanHD 1 Reply Last reply Reply Quote 0
                • DanHD
                  DanH @griffinboy
                  last edited by DanH

                  @griffinboy just got round to testing and it works well for boosting 2nd / 4th / 6th etc harmonics - all the even ones (My understanding is that the fundamental and the first harmonic are the same frequency). Sounds quite good in tandem with a distortion module and also good for adding a harmonic to sub bass :) So a big thanks for putting this together!

                  Were there meant to be some controls in the SNEX Shaper? Because nothing appears when the code is compiled...

                  I'm not sure I get your method of increasing the level of the fundamental. I need the mix to be at full anyway (unless I've misunderstood your suggestion). The picture below is a 50hz tone run through the distortion I'm trying to emulate and my own emulation layered on top. The key difference which I'm trying to emulate right now is the obvious increased level of the original distortion at 50hz (or the fundamental of any signal running through it).

                  DIZ.png

                  DHPlugins / DC Breaks | Artist / Producer / DJ / Developer
                  https://dhplugins.com/ | https://dcbreaks.com/
                  London, UK

                  Matt_SFM 1 Reply Last reply Reply Quote 0
                  • Matt_SFM
                    Matt_SF @DanH
                    last edited by Matt_SF

                    @DanH said in Distortion Whiz required...:

                    Were there meant to be some controls in the SNEX Shaper? Because nothing appears when the code is compiled...

                    Click on the 3 dots on the top-left corner of the SNEX node, select "Add Parameter" and give it a name.

                    Here you can then specify which variable you want to change using the knob :

                        // Set the parameters here
                    	template <int P> void setParameter(double v)
                        	{
                        		if(P == 0)
                        		{	
                        			drive= (float)v;
                        		}
                        		if(P == 1)
                        		{	
                        			mix= (float)v;
                        		}
                        		if(P == 2)
                        		{	
                        			bias= (float)v;
                        		}
                                    // etc...
                        	}
                    

                    Develop branch
                    Win10 & VS17 / Ventura & Xcode 14. 3

                    DanHD 1 Reply Last reply Reply Quote 0
                    • DanHD
                      DanH @Matt_SF
                      last edited by

                      @Matt_SF thanks!

                      DHPlugins / DC Breaks | Artist / Producer / DJ / Developer
                      https://dhplugins.com/ | https://dcbreaks.com/
                      London, UK

                      griffinboyG 1 Reply Last reply Reply Quote 0
                      • griffinboyG
                        griffinboy @DanH
                        last edited by griffinboy

                        @DanH

                        If I'm honest, those controls were removed because the algorithm was acting up. I wrote this one when I had much less understanding of distortion. It was meant to be a chebyshev waveshaper but it went wrong!

                        In the following months I've been developing a much more accurate method for designing distortions. I shall be sharing it when it is ready.

                        1 Reply Last reply Reply Quote 0
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