Added boundary states for correct resonances

Core/SoundProcessor.cs

@@ -0,0 +1,23 @@
+namespace FluidSim.Core
+{
+    /// <summary>
+    /// Mixes multiple audio samples and applies a soft‑clipping tanh.
+    /// </summary>
+    public static class SoundProcessor
+    {
+        /// <summary>Overall gain applied after mixing (before tanh).</summary>
+        public static float MasterGain { get; set; } = 0.01f;
+
+        /// <summary>
+        /// Mixes an array of raw audio samples and returns a single sample in [‑1, 1].
+        /// </summary>
+        public static float MixAndClip(params float[] samples)
+        {
+            float sum = 0f;
+            foreach (float s in samples)
+                sum += s;
+            sum *= MasterGain;
+            return sum;
+        }
+    }
+}