diff --git a/src/cpp/viper/utils/FIR.cpp b/src/cpp/viper/utils/FIR.cpp
index 996390b..b043e3b 100644
--- a/src/cpp/viper/utils/FIR.cpp
+++ b/src/cpp/viper/utils/FIR.cpp
@@ -1,7 +1,13 @@
+#include <cstring>
 #include "FIR.h"
 
 FIR::FIR() {
-
+    this->offsetBlock = nullptr;
+    this->coeffs = nullptr;
+    this->block = nullptr;
+    this->coeffsSize = 0;
+    this->blockLength = 0;
+    this->hasCoefficients = false;
 }
 
 FIR::~FIR() {
@@ -15,21 +21,63 @@ void FIR::FilterSamples(float *samples, uint32_t size) {
 }
 
 void FIR::FilterSamplesInterleaved(float *samples, uint32_t size, uint32_t channels) {
+    if (!this->hasCoefficients || size == 0) return;
 
+    for (uint32_t i = 0; i < size; i++) {
+        this->block[i] = samples[i * channels];
+    }
+
+    if (this->blockLength > size) {
+        memset(&this->block[size], 0, (this->blockLength - size) * sizeof(float));
+    }
+
+    memcpy(&this->offsetBlock[this->coeffsSize - 1], this->block, this->blockLength * sizeof(float));
+
+    for (uint32_t i = 0; i < this->blockLength; i++) {
+        float sample = 0.0f;
+
+        for (uint32_t j = 0; j < this->coeffsSize; j++) {
+            sample += this->coeffs[j] * this->offsetBlock[this->coeffsSize + i - 1 - j];
+        }
+
+        if (i < size) {
+            samples[channels * i] = sample;
+        }
+    }
+
+    if (this->coeffsSize > 1) {
+        memcpy(&this->offsetBlock[this->coeffsSize - 2], &this->block[this->blockLength - 1], this->blockLength - (this->coeffsSize - 1) * sizeof(float));
+    }
 }
 
-int FIR::GetBlockLength() {
+uint32_t FIR::GetBlockLength() {
     return this->blockLength;
 }
 
-int FIR::LoadCoefficients(const float *coeffs, uint32_t coeffsize, int blockLength) {
-    return 0;
+int FIR::LoadCoefficients(const float *coeffs, uint32_t coeffsSize, uint32_t blockLength) {
+    if (coeffs == nullptr || coeffsSize == 0 || blockLength == 0) return 0;
+
+    delete this->offsetBlock;
+    delete this->coeffs;
+    delete this->block;
+
+    this->offsetBlock = new float[coeffsSize + blockLength + 1];
+    this->coeffs = new float[coeffsSize];
+    this->block = new float[blockLength];
+
+    this->coeffsSize = coeffsSize;
+    this->blockLength = blockLength;
+
+    memcpy(this->coeffs, coeffs, coeffsSize * sizeof(float));
+
+    this->Reset();
+    this->hasCoefficients = true;
+
+    return 1;
 }
 
 void FIR::Reset() {
-    if (this->offsetBlock != nullptr && this->coeffsize + this->blockLength > -1) {
-        for (int i = 0; i < this->coeffsize + this->blockLength; i++) {
-            this->offsetBlock[i] = 0;
-        }
+    if (this->offsetBlock != nullptr && this->coeffsSize + this->blockLength > 0) {
+        memset(this->offsetBlock, 0, (this->coeffsSize + this->blockLength) * sizeof(float));
     }
 }
diff --git a/src/cpp/viper/utils/FIR.h b/src/cpp/viper/utils/FIR.h
index e8b8806..b73d102 100644
--- a/src/cpp/viper/utils/FIR.h
+++ b/src/cpp/viper/utils/FIR.h
@@ -9,18 +9,17 @@ public:
 
     void FilterSamples(float *samples, uint32_t size);
     void FilterSamplesInterleaved(float *samples, uint32_t size, uint32_t channels);
-    int GetBlockLength();
-    int LoadCoefficients(const float *coeffs, uint32_t coeffsize, int blockLength);
+    uint32_t GetBlockLength();
+    int LoadCoefficients(const float *coeffs, uint32_t coeffsSize, uint32_t blockLength);
     void Reset();
 
 private:
-    int *offsetBlock;
+    float *offsetBlock;
     float *coeffs;
     float *block;
-    int coeffsize;
-    int blockLength;
-    bool enabled;
-
+    uint32_t coeffsSize;
+    uint32_t blockLength;
+    bool hasCoefficients;
 };