diff --git a/ProjectObsidian/ProjectObsidian.csproj b/ProjectObsidian/ProjectObsidian.csproj
index 6f42d64..462344f 100644
--- a/ProjectObsidian/ProjectObsidian.csproj
+++ b/ProjectObsidian/ProjectObsidian.csproj
@@ -3,7 +3,7 @@
     <RootNamespace>Project-Obsidian</RootNamespace>
     <AssemblyName>Project-Obsidian</AssemblyName>
     <TargetFramework>net48</TargetFramework>
-    <LangVersion>11</LangVersion>
+    <LangVersion>12</LangVersion>
     <Copyright>Copyright ©  2024</Copyright>
     <Product>Project-Obsidian</Product>
   </PropertyGroup>
diff --git a/ProjectObsidian/ProtoFlux/Math/FrequencyQuantize.cs b/ProjectObsidian/ProtoFlux/Math/FrequencyQuantize.cs
new file mode 100644
index 0000000..6f2be63
--- /dev/null
+++ b/ProjectObsidian/ProtoFlux/Math/FrequencyQuantize.cs
@@ -0,0 +1,162 @@
+using System;
+using ProtoFlux.Core;
+using ProtoFlux.Runtimes.Execution;
+using FrooxEngine.ProtoFlux;
+using FrooxEngine;
+using Elements.Assets;
+using Elements.Core;
+using System.Linq;
+using System.Collections.Generic;
+
+namespace ProtoFlux.Runtimes.Execution.Nodes.Obsidian.Math
+{
+    [DataModelType]
+    public enum NoteScale
+    {
+        Chromatic,
+        Major,
+        Minor,
+        Blues,
+        Dorian,
+        Phrygian,
+        Lydian,
+        Mixolydian,
+        Locrian
+    }
+
+    [NodeCategory("Obsidian/Math")]
+    public class FrequencyQuantize : VoidNode<FrooxEngineContext>
+    {
+        public readonly ValueInput<float> Frequency;
+        public readonly ValueInput<NoteScale> Scale;
+        public readonly ValueInput<bool> RoundToNearest;
+
+        public readonly ValueInput<int> Offset;
+
+        public readonly ValueOutput<float> QuantizedFrequency;
+        public readonly ValueOutput<bool> InScale;
+
+        public static readonly List<int> ChromaticScale = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
+        public static readonly List<int> MajorScale = [0, 2, 4, 5, 7, 9, 11];
+        public static readonly List<int> MinorScale = [0, 2, 3, 5, 7, 8, 10];
+        public static readonly List<int> BluesScale = [0, 3, 5, 6, 7, 10];
+        public static readonly List<int> DorianScale = [0, 2, 3, 5, 7, 9, 10];
+        public static readonly List<int> PhrygianScale = [0, 1, 3, 5, 7, 8, 10];
+        public static readonly List<int> LydianScale = [0, 2, 4, 6, 7, 9, 11];
+        public static readonly List<int> MixolydianScale = [0, 2, 4, 5, 7, 9, 10];
+        public static readonly List<int> LocrianScale = [0, 1, 3, 5, 6, 8, 10];
+
+        private static int FreqToNearestMidi(float freq)
+        {
+            var n = 12f * (float)System.Math.Log(freq / 440f, 2f) + 69f;
+            return (int)MathX.Round(n, MidpointRounding.AwayFromZero);
+        }
+
+        private static float MidiToFreq(int midi)
+        {
+            return 440f * MathX.Pow(2, (midi - 69f) / 12f);
+        }
+
+        protected override void ComputeOutputs(FrooxEngineContext context)
+        {
+            var freq = Frequency.Evaluate(context);
+            
+            var offset = Offset.Evaluate(context);
+            var rootNote = 69 + offset;
+
+            var midi = FreqToNearestMidi(freq);
+
+            bool inScale = false;
+            List<int> scaleList;
+            switch (Scale.Evaluate(context))
+            {
+                case NoteScale.Chromatic:
+                    scaleList = ChromaticScale;
+                    break;
+                case NoteScale.Major:
+                    scaleList = MajorScale;
+                    break;
+                case NoteScale.Minor:
+                    scaleList = MinorScale;
+                    break;
+                case NoteScale.Blues:
+                    scaleList = BluesScale;
+                    break;
+                case NoteScale.Dorian:
+                    scaleList = DorianScale;
+                    break;
+                case NoteScale.Phrygian:
+                    scaleList = PhrygianScale;
+                    break;
+                case NoteScale.Lydian:
+                    scaleList = LydianScale;
+                    break;
+                case NoteScale.Mixolydian:
+                    scaleList = MixolydianScale;
+                    break;
+                case NoteScale.Locrian:
+                    scaleList = LocrianScale;
+                    break;
+                default:
+                    scaleList = ChromaticScale;
+                    break;
+            }
+            foreach (var note in scaleList)
+            {
+                var scaleDegree = (midi - rootNote) % 12;
+                if (scaleDegree < 0) scaleDegree += 12;
+                if (note == scaleDegree)
+                {
+                    inScale = true;
+                    break;
+                }
+            }
+            if (!inScale)
+            {
+                if (RoundToNearest.Evaluate(context))
+                {
+                    int scaleDegree = (midi - rootNote) % 12;
+                    if (scaleDegree < 0)
+                        scaleDegree += 12;
+
+                    int closestSemitone = scaleList[0];
+                    int minDifference = int.MaxValue;
+
+                    foreach (int scaleSemitone in scaleList)
+                    {
+                        int difference = MathX.Abs(scaleDegree - scaleSemitone);
+                        if (difference < minDifference)
+                        {
+                            minDifference = difference;
+                            closestSemitone = scaleSemitone;
+                        }
+                    }
+
+                    int octave = (midi - rootNote) / 12;
+
+                    midi += closestSemitone - scaleDegree;
+
+                    //UniLog.Log($"midi: {midi} octave: {octave} rootNote: {rootNote} closestSemitone: {closestSemitone} scaleDegree: {scaleDegree}");
+
+                    inScale = true;
+                }
+            }
+            InScale.Write(inScale, context);
+            if (inScale)
+            {
+                var res = MidiToFreq(midi);
+                QuantizedFrequency.Write(res, context);
+            }
+            else
+            {
+                QuantizedFrequency.Write(0f, context);
+            }
+        }
+
+        public FrequencyQuantize()
+        {
+            QuantizedFrequency = new ValueOutput<float>(this);
+            InScale = new ValueOutput<bool>(this);
+        }
+    }
+}
\ No newline at end of file
diff --git a/ProjectObsidian/ProtoFlux/Math/MIDI_NoteFrequency.cs b/ProjectObsidian/ProtoFlux/Math/MIDI_NoteFrequency.cs
new file mode 100644
index 0000000..78e7f61
--- /dev/null
+++ b/ProjectObsidian/ProtoFlux/Math/MIDI_NoteFrequency.cs
@@ -0,0 +1,21 @@
+using System;
+using ProtoFlux.Core;
+using ProtoFlux.Runtimes.Execution;
+using FrooxEngine.ProtoFlux;
+using FrooxEngine;
+using Elements.Assets;
+using Elements.Core;
+
+namespace ProtoFlux.Runtimes.Execution.Nodes.Obsidian.Math
+{
+    [NodeCategory("Obsidian/Math")]
+    public class MIDI_NoteFrequency : ValueFunctionNode<FrooxEngineContext, float>
+    {
+        public readonly ValueInput<int> NoteNumber;
+        protected override float Compute(FrooxEngineContext context)
+        {
+            var note = NoteNumber.Evaluate(context);
+            return 440f * MathX.Pow(2, (note - 69f) / 12f);
+        }
+    }
+}
\ No newline at end of file