diff --git a/filter_ladder.cpp b/filter_ladder.cpp
index 4b141eba..d5a6494f 100644
--- a/filter_ladder.cpp
+++ b/filter_ladder.cpp
@@ -46,10 +46,24 @@
 #define MAX_FREQUENCY ((float)(AUDIO_SAMPLE_RATE_EXACT * 0.425f))
 
 
+float AudioFilterLadder::interpolation_coeffs[AudioFilterLadder::interpolation_taps] = {
+-14.30851541590154240E-6,  0.001348560352009071, 0.004029285548698377, 0.007644563345368599,
+0.010936856250494802, 0.011982063548666887, 0.008882946305001046, 826.6598116471556070E-6,
+-0.011008071930708746,-0.023014151355548934,-0.029736402750934567,-0.025405787911977455,
+-0.006012006772274640, 0.028729626071574525, 0.074466890595619062, 0.122757573409695370,
+0.163145421379242955, 0.186152844567746417, 0.186152844567746417, 0.163145421379242955,
+0.122757573409695370, 0.074466890595619062, 0.028729626071574525,-0.006012006772274640,
+-0.025405787911977455,-0.029736402750934567,-0.023014151355548934,-0.011008071930708746,
+826.6598116471556070E-6, 0.008882946305001046, 0.011982063548666887, 0.010936856250494802,
+0.007644563345368599, 0.004029285548698377, 0.001348560352009071,-14.30851541590154240E-6
+};
+
+#define I_NUM_SAMPLES  AUDIO_BLOCK_SAMPLES * INTERPOLATION
+
 void AudioFilterLadder::initpoly()
 {
 	if (arm_fir_interpolate_init_f32(&interpolation, INTERPOLATION, interpolation_taps,
-	   interpolation_coeffs, interpolation_state, NUM_SAMPLES)) {
+	   interpolation_coeffs, interpolation_state, AUDIO_BLOCK_SAMPLES)) {
 		Serial.println("Init of interpolation failed");
 		while (1);
 	}
@@ -219,7 +233,7 @@ void AudioFilterLadder::update(void)
 		for (int i=0; i < AUDIO_BLOCK_SAMPLES; i++) {
 			blockIn[i] = blocka->data[i] * overdrive * (float)INTERPOLATION / 32768.0f;
 		}
-		arm_fir_interpolate_f32(&interpolation, blockIn, blockOS, NUM_SAMPLES);
+		arm_fir_interpolate_f32(&interpolation, blockIn, blockOS, AUDIO_BLOCK_SAMPLES);
 
 		for (int i=0; i < AUDIO_BLOCK_SAMPLES; i++) {
 			if (FCmodActive) {
diff --git a/filter_ladder.h b/filter_ladder.h
index 2258d07f..bcd986f2 100644
--- a/filter_ladder.h
+++ b/filter_ladder.h
@@ -38,37 +38,12 @@
 #ifndef filter_ladder_h_
 #define filter_ladder_h_
 
-#define LINEAR 0
-#define FIR_POLY 1
 #include "Arduino.h"
 #include "AudioStream.h"
 #include "arm_math.h"
 #define LINEAR 0
 #define FIR_POLY 1
-#define INTERPOLATION  4
-#define INTERPOLATIONscaler  4
-#define I_SAMPLERATE  AUDIO_SAMPLE_RATE_EXACT * INTERPOLATION
-#define NUM_SAMPLES  128
-#define I_NUM_SAMPLES  NUM_SAMPLES * INTERPOLATION
 
-/*
-#define interpolation_taps 32
-static float interpolation_coeffs[interpolation_taps] = {
-444.8708144065367380E-6, 0.002132195798620151, 0.004238318820060649, 0.005517336264360800, 0.004277228394758379,-780.0288538232418890E-6,-0.009468419595216885,-0.019306296307004593,
--0.025555801376824804,-0.022415559173490765,-0.005152700802329096, 0.027575475722578378, 0.072230543044204509, 0.120566259375849666, 0.161676773663769008, 0.185322994251944373,
- 0.185322994251944373, 0.161676773663769008, 0.120566259375849666, 0.072230543044204509, 0.027575475722578378,-0.005152700802329096,-0.022415559173490765,-0.025555801376824804,
--0.019306296307004593,-0.009468419595216885,-780.0288538232418890E-6, 0.004277228394758379, 0.005517336264360800, 0.004238318820060649, 0.002132195798620151, 444.8708144065367380E-6
-};
-*/
-
-#define interpolation_taps 36
-static float interpolation_coeffs[interpolation_taps] = {
--14.30851541590154240E-6,  0.001348560352009071, 0.004029285548698377, 0.007644563345368599, 0.010936856250494802, 0.011982063548666887, 0.008882946305001046, 826.6598116471556070E-6,
--0.011008071930708746,-0.023014151355548934,-0.029736402750934567,-0.025405787911977455,-0.006012006772274640, 0.028729626071574525, 0.074466890595619062, 0.122757573409695370,
- 0.163145421379242955, 0.186152844567746417, 0.186152844567746417, 0.163145421379242955, 0.122757573409695370, 0.074466890595619062, 0.028729626071574525,-0.006012006772274640,
--0.025405787911977455,-0.029736402750934567,-0.023014151355548934,-0.011008071930708746, 826.6598116471556070E-6, 0.008882946305001046, 0.011982063548666887, 0.010936856250494802,
- 0.007644563345368599, 0.004029285548698377, 0.001348560352009071,-14.30851541590154240E-6
-};
 
 class AudioFilterLadder: public AudioStream
 {
@@ -83,10 +58,13 @@ class AudioFilterLadder: public AudioStream
 	void initpoly();
 	virtual void update(void);
 private:
-	float interpolation_state[(NUM_SAMPLES-1) + interpolation_taps / INTERPOLATION];
+	static const int INTERPOLATION = 4;
+	static const int interpolation_taps = 36;
+	float interpolation_state[(AUDIO_BLOCK_SAMPLES-1) + interpolation_taps / INTERPOLATION];
 	arm_fir_interpolate_instance_f32 interpolation;
-	float decimation_state[(I_NUM_SAMPLES-1) + interpolation_taps];
+	float decimation_state[(AUDIO_BLOCK_SAMPLES*INTERPOLATION-1) + interpolation_taps];
 	arm_fir_decimate_instance_f32 decimation;
+	static float interpolation_coeffs[interpolation_taps];
 	float LPF(float s, int i);
 	void compute_coeffs(float fc);
 	bool resonating();