diff --git a/filter/iir.h b/filter/iir.h
index 744bb46..5a23fec 100644
--- a/filter/iir.h
+++ b/filter/iir.h
@@ -21,5 +21,5 @@ typedef struct {
     float y_prev;
 } TiltCorrectionFilter;
 
-void tilt_init(TiltCorrectionFilter *filter, float correction_strength);
-float tilt(TiltCorrectionFilter *filter, float input_sample);
+void tilt_init(TiltCorrectionFilter* filter, float cutoff_freq, float sample_rate);
+float tilt(TiltCorrectionFilter *filter, float input);