The filters have to be initialized with samplerate

src/sfizz/FilterPool.cpp

@@ -59,7 +59,7 @@ void sfz::FilterHolder::process(const float** inputs, float** outputs, unsigned
 
     lastGain = baseGain;
     for (auto& mod: description->gainCC) {
-        lastResonance += midiState.getCCValue(mod.first) * mod.second;
+        lastGain += midiState.getCCValue(mod.first) * mod.second;
     }
 
     filter.process(inputs, outputs, lastCutoff, lastResonance, lastGain, numFrames);
@@ -132,3 +132,14 @@ size_t sfz::FilterPool::setNumFilters(size_t numFilters)
 
     return filters.size();
 }
+
+void sfz::FilterPool::setSampleRate(float sampleRate)
+{
+    for (auto& filter: filters)
+        filter->setSampleRate(sampleRate);
+}
+
+void sfz::FilterHolder::setSampleRate(float sampleRate)
+{
+    filter.init(static_cast<double>(sampleRate));
+}

src/sfizz/FilterPool.h

@@ -47,6 +47,12 @@ public:
      * @return float
      */
     float getLastGain() const;
+    /**
+     * @brief Set the sample rate for a filter
+     *
+     * @param sampleRate
+     */
+    void setSampleRate(float sampleRate);
 private:
     /**
      * Reset the filter. Is called internally when using setup().
@@ -103,10 +109,16 @@ public:
      * @return size_t the actual number of filters in the pool
      */
     size_t setNumFilters(size_t numFilters);
+    /**
+     * @brief Set the sample rate for all filters
+     *
+     * @param sampleRate
+     */
+    void setSampleRate(float sampleRate);
 private:
     std::atomic<bool> givingOutFilters { false };
     std::atomic<bool> canGiveOutFilters { true };
-
+    float sampleRate { config::defaultSampleRate };
     const MidiState& midiState;
     std::vector<FilterHolderPtr> filters;
 };

src/sfizz/Synth.cpp

@@ -401,6 +401,8 @@ void sfz::Synth::setSampleRate(float sampleRate) noexcept
     this->sampleRate = sampleRate;
     for (auto& voice : voices)
         voice->setSampleRate(sampleRate);
+
+    resources.filterPool.setSampleRate(sampleRate);
 }
 
 void sfz::Synth::renderBlock(AudioSpan<float> buffer) noexcept