diff --git a/src/lib/mathlib/math/filter/LowPassFilter2p.hpp b/src/lib/mathlib/math/filter/LowPassFilter2p.hpp
index 2ecc17f652..fd3a531e03 100644
--- a/src/lib/mathlib/math/filter/LowPassFilter2p.hpp
+++ b/src/lib/mathlib/math/filter/LowPassFilter2p.hpp
@@ -72,7 +72,7 @@ public:
 		_cutoff_freq = math::constrain(cutoff_freq, 5.f, sample_freq / 2); // TODO: min based on actual numerical limit
 		_sample_freq = sample_freq;
 
-		const float fr = sample_freq / _cutoff_freq;
+		const float fr = _sample_freq / _cutoff_freq;
 		const float ohm = tanf(M_PI_F / fr);
 		const float c = 1.f + 2.f * cosf(M_PI_F / 4.f) * ohm + ohm * ohm;
 
diff --git a/src/lib/mathlib/math/filter/NotchFilter.hpp b/src/lib/mathlib/math/filter/NotchFilter.hpp
index 0049022a72..5bf99a7119 100644
--- a/src/lib/mathlib/math/filter/NotchFilter.hpp
+++ b/src/lib/mathlib/math/filter/NotchFilter.hpp
@@ -201,8 +201,8 @@ void NotchFilter<T>::setParameters(float sample_freq, float notch_freq, float ba
 	_bandwidth = math::constrain(bandwidth, 5.f, sample_freq / 2);
 	_sample_freq = sample_freq;
 
-	const float alpha = tanf(M_PI_F * bandwidth / sample_freq);
-	const float beta = -cosf(2.f * M_PI_F * notch_freq / sample_freq);
+	const float alpha = tanf(M_PI_F * _bandwidth / _sample_freq);
+	const float beta = -cosf(2.f * M_PI_F * _notch_freq / _sample_freq);
 	const float a0_inv = 1.f / (alpha + 1.f);
 
 	_b0 = a0_inv;