diff --git a/src/fvOptions/sources/derived/acousticDampingSource/acousticDampingSource.C b/src/fvOptions/sources/derived/acousticDampingSource/acousticDampingSource.C
index af3d504760bcc1f856785b2e3d39081903c45da5..8b5cad4be5939e7925289b9abded8bce1b2ce7a9 100644
--- a/src/fvOptions/sources/derived/acousticDampingSource/acousticDampingSource.C
+++ b/src/fvOptions/sources/derived/acousticDampingSource/acousticDampingSource.C
@@ -67,9 +67,9 @@ void Foam::fv::acousticDampingSource::setBlendingFactor()
         {
             blendFactor_[celli] = 0.0;
         }
-        else if ((d >= r1_) && (d <= (r1_ + r2_)))
+        else if ((d >= r1_) && (d <= r2_))
         {
-            blendFactor_[celli] = (1.0 - cos(pi*mag(d - r1_)/r2_))/2.0;
+            blendFactor_[celli] = (1.0 - cos(pi*mag(d - r1_)/(r2_ - r1_)))/2.0;
         }
     }