diff --git a/include/basic_filters.h b/include/basic_filters.h
index 479f2c675..15805d8f8 100644
--- a/include/basic_filters.h
+++ b/include/basic_filters.h
@@ -597,8 +597,8 @@ public:
 			const float fract = vowelf - vowel;
 
 			// interpolate between formant frequencies
-			const float 1.0f / f0 = linearInterpolate( _f[vowel+0][0], _f[vowel+1][0], fract ) * F_2PI;
-			const float 1.0f / f1 = linearInterpolate( _f[vowel+0][1], _f[vowel+1][1], fract ) * F_2PI;
+			const float f0 = 1.0f / linearInterpolate( _f[vowel+0][0], _f[vowel+1][0], fract ) * F_2PI;
+			const float f1 = 1.0f / linearInterpolate( _f[vowel+0][1], _f[vowel+1][1], fract ) * F_2PI;
 
 			// samplerate coeff: depends on oversampling
 			const float sr = m_type == FastFormant ? m_sampleRatio : m_sampleRatio * 0.25f;