diff --git a/src/sfizz/FlexEnvelope.h b/src/sfizz/FlexEnvelope.h
index c33bf751..a72d280f 100644
--- a/src/sfizz/FlexEnvelope.h
+++ b/src/sfizz/FlexEnvelope.h
@@ -5,7 +5,6 @@
 // If not, contact the sfizz maintainers at https://github.com/sfztools/sfizz
 
 #pragma once
-#include "MidiState.h"
 #include <absl/types/span.h>
 #include <memory>
 
diff --git a/src/sfizz/Synth.cpp b/src/sfizz/Synth.cpp
index 46b9f52d..1e200b58 100644
--- a/src/sfizz/Synth.cpp
+++ b/src/sfizz/Synth.cpp
@@ -70,7 +70,7 @@ Synth::Impl::Impl()
     MidiState& midiState = resources_.getMidiState();
     genController_.reset(new ControllerSource(resources_, voiceManager_));
     genLFO_.reset(new LFOSource(voiceManager_));
-    genFlexEnvelope_.reset(new FlexEnvelopeSource(voiceManager_, midiState));
+    genFlexEnvelope_.reset(new FlexEnvelopeSource(voiceManager_));
     genADSREnvelope_.reset(new ADSREnvelopeSource(voiceManager_, midiState));
     genChannelAftertouch_.reset(new ChannelAftertouchSource(voiceManager_, midiState));
     genPolyAftertouch_.reset(new PolyAftertouchSource(voiceManager_, midiState));
diff --git a/src/sfizz/modulations/sources/FlexEnvelope.cpp b/src/sfizz/modulations/sources/FlexEnvelope.cpp
index 1a2698ad..347886aa 100644
--- a/src/sfizz/modulations/sources/FlexEnvelope.cpp
+++ b/src/sfizz/modulations/sources/FlexEnvelope.cpp
@@ -14,8 +14,8 @@
 
 namespace sfz {
 
-FlexEnvelopeSource::FlexEnvelopeSource(VoiceManager& manager, MidiState& midiState)
-    : voiceManager_(manager), midiState_(midiState)
+FlexEnvelopeSource::FlexEnvelopeSource(VoiceManager& manager)
+    : voiceManager_(manager)
 {
 
 }
diff --git a/src/sfizz/modulations/sources/FlexEnvelope.h b/src/sfizz/modulations/sources/FlexEnvelope.h
index 60cd5b14..81b7a2f7 100644
--- a/src/sfizz/modulations/sources/FlexEnvelope.h
+++ b/src/sfizz/modulations/sources/FlexEnvelope.h
@@ -7,14 +7,13 @@
 #pragma once
 #include "../ModGenerator.h"
 #include "../../VoiceManager.h"
-#include "../../MidiState.h"
 
 namespace sfz {
 class Synth;
 
 class FlexEnvelopeSource : public ModGenerator {
 public:
-    explicit FlexEnvelopeSource(VoiceManager& manager, MidiState& midiState);
+    explicit FlexEnvelopeSource(VoiceManager& manager);
     void init(const ModKey& sourceKey, NumericId<Voice> voiceId, unsigned delay) override;
     void release(const ModKey& sourceKey, NumericId<Voice> voiceId, unsigned delay) override;
     void cancelRelease(const ModKey& sourceKey, NumericId<Voice> voiceId, unsigned delay) override;
@@ -22,7 +21,6 @@ public:
 
 private:
     VoiceManager& voiceManager_;
-    MidiState& midiState_;
 };
 
 } // namespace sfz