diff --git a/inc/Renderer.h b/inc/Renderer.h
index fccd7a6..c3906ad 100644
--- a/inc/Renderer.h
+++ b/inc/Renderer.h
@@ -1,4 +1,5 @@
 #pragma once
+#include "Filter.h"
 #include "ADSR.h"
 #include "Synth.h"
 #include "SynthGuiState.h"
@@ -19,7 +20,8 @@ class Renderer {
     void draw_signal(Synth& synth, SynthGuiState& synth_gui);
     void draw_adsr_panel(ADSR* adsr, ADSRGuiState& gui_adsr,
                          const Rectangle& panel_bounds, float panel_y_offset);
-
+    void draw_second_panel(Rectangle& bounds);
+    float draw_filter_panel(Filter* filter, FilterGuiState& gui_filter, const Rectangle& panel_bounds);
   public:
     Renderer(/* args */);
     ~Renderer();
diff --git a/inc/Synth.h b/inc/Synth.h
index eb12ea0..4c1ffbd 100644
--- a/inc/Synth.h
+++ b/inc/Synth.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "ADSR.h"
+#include "Filter.h"
 #include "Adder.h"
 #include "Effect.h"
 #include "Note.h"
@@ -32,4 +33,5 @@ class Synth {
     const std::vector<Oscillator*>& GetOscillators() { return m_oscillators; }
     const bool& GetIsNoteTriggered() { return is_note_triggered; }
     ADSR* GetADSR() { return (ADSR*)m_effects[0]; }
+    Filter* GetFilter() { return (Filter*)m_effects[1]; }
 };
\ No newline at end of file
diff --git a/inc/SynthGuiState.h b/inc/SynthGuiState.h
index f07a21d..778e1b7 100644
--- a/inc/SynthGuiState.h
+++ b/inc/SynthGuiState.h
@@ -18,7 +18,14 @@ struct ADSRGuiState {
     float release;
 };
 
+struct FilterGuiState {
+    float freq;
+    float res;
+    //todo: type
+};
+
 struct SynthGuiState {
     std::vector<OscillatorGuiState*> oscillators;
     ADSRGuiState adsr;
+    FilterGuiState filter;
 };
\ No newline at end of file
diff --git a/src/Filter.cpp b/src/Filter.cpp
index 7fcde3d..a841796 100644
--- a/src/Filter.cpp
+++ b/src/Filter.cpp
@@ -1,4 +1,5 @@
 #include "Filter.h"
+#include "Settings.h"
 
 Filter::Filter(/* args */) {
 }
@@ -37,7 +38,7 @@ void Filter::Process(std::vector<float>& samples) {
 }
 
 void Filter::SetParameters(float freq, float res, float q) {
-    m_freq = freq;
+    m_freq = freq / SAMPLE_RATE;
     m_q = res;
     m_order = q;
 }
diff --git a/src/Renderer.cpp b/src/Renderer.cpp
index e3db365..1360e62 100644
--- a/src/Renderer.cpp
+++ b/src/Renderer.cpp
@@ -185,6 +185,57 @@ void Renderer::draw_adsr_panel(ADSR* adsr, ADSRGuiState& gui_adsr,
                         gui_adsr.release);
 }
 
+void Renderer::draw_second_panel(Rectangle& bounds) {
+    bounds.x += bounds.width;
+    GuiPanel(bounds, "");
+}
+
+float Renderer::draw_filter_panel(Filter* filter, FilterGuiState& gui_filter, const Rectangle& panel_bounds) {
+    float panel_y_offset = 0;
+
+    // Draw Filter Panel
+    const int osc_panel_width = panel_bounds.width - 20;
+    const int osc_panel_height = 120;
+    const int osc_panel_x = panel_bounds.x + 10;
+    const int osc_panel_y = panel_bounds.y + 50;
+    panel_y_offset += osc_panel_height + 5;
+    GuiPanel((Rectangle){(float)osc_panel_x, (float)osc_panel_y,
+                         (float)osc_panel_width, (float)osc_panel_height},
+             "Filter");
+
+    const float slider_padding = 50.f;
+    const float el_spacing = 5.f;
+    Rectangle el_rect = {.x = (float)osc_panel_x + slider_padding + 30,
+                         .y = (float)osc_panel_y + 10,
+                         .width = (float)osc_panel_width - (slider_padding * 2),
+                         .height = 25.f};
+
+    // Frequency slider
+    float freq = gui_filter.freq;
+    char freq_slider_label[32];
+    snprintf(freq_slider_label, 10, "%.1f hz", freq);
+    freq = GuiSlider(el_rect, freq_slider_label, "", freq, 0.0f, 16000.f);
+    gui_filter.freq = freq;
+    el_rect.y += el_rect.height + el_spacing;
+
+    // Resonance slider
+    float res = gui_filter.res;
+    char res_slider_label[32];
+    snprintf(res_slider_label, 7, "%.1f u", res);
+    res = GuiSlider(el_rect, res_slider_label, "", res, 0.0f, 1.0f);
+    gui_filter.res = res;
+    el_rect.y += el_rect.height + el_spacing;
+
+    // todo: filter type
+
+    // apply values to real one
+    // todo: thrid (order) parameter
+    // todo: why resonance changing does not work?
+    filter->SetParameters(gui_filter.freq, 0.707, 0);
+
+    return panel_y_offset;
+}
+
 void Renderer::draw_ui(Synth& synth, SynthGuiState& synth_gui) {
     Rectangle panel_bounds = {.x = 0,
                               .y = 0,
@@ -200,4 +251,7 @@ void Renderer::draw_ui(Synth& synth, SynthGuiState& synth_gui) {
     draw_adsr_panel(synth.GetADSR(), synth_gui.adsr, panel_bounds,
                     panel_y_offset);
     draw_oscillators_shape_inputs(oscillators, gui_oscillators);
+
+    draw_second_panel(panel_bounds);
+    draw_filter_panel(synth.GetFilter(), synth_gui.filter, panel_bounds);
 }
diff --git a/src/Synth.cpp b/src/Synth.cpp
index b924043..1ea0484 100644
--- a/src/Synth.cpp
+++ b/src/Synth.cpp
@@ -1,5 +1,4 @@
 #include "Synth.h"
-#include "ADSR.h"
 #include "KeyBoard.h"
 #include "Logger.h"
 #include "OscillatorType.h"