diff --git a/lib/averages/Dsma.cs b/lib/averages/Dsma.cs
index 93fbdede..98c7b7e3 100644
--- a/lib/averages/Dsma.cs
+++ b/lib/averages/Dsma.cs
@@ -50,8 +50,9 @@ public class Dsma : AbstractBase
         _buffer = new CircularBuffer(period);
 
         // SuperSmoother filter coefficients
-        _a1 = Math.Exp(-1.414 * Math.PI / (0.5 * period));
-        _b1 = 2 * _a1 * Math.Cos(1.414 * Math.PI / (0.5 * period));
+        double _a1 = Math.Exp(-1.414 * Math.PI / (0.5 * period));
+        double _b1 = 2 * _a1 * Math.Cos(1.414 * Math.PI / (0.5 * period));
+        
         _c2 = _b1;
         _c3 = -_a1 * _a1;
         _c1 = 1 - _c2 - _c3;