diff --git a/src/sfizz/Synth.cpp b/src/sfizz/Synth.cpp
index 3e7155d7..02e3ff27 100644
--- a/src/sfizz/Synth.cpp
+++ b/src/sfizz/Synth.cpp
@@ -253,15 +253,6 @@ struct Synth::Impl : public Voice::StateListener, public Parser::Listener {
      */
     void startDelayedReleaseVoices(Region* region, int delay, SisterVoiceRingBuilder& ring) noexcept;
 
-    /**
-     * @brief Check if a playing voice matches the release region
-     *
-     * @param releaseRegion
-     * @return true
-     * @return false
-     */
-    bool playingAttackVoice(const Region* releaseRegion) noexcept;
-
     /**
      * @brief Finalize SFZ loading, following a successful execution of the
      *        parsing step.
@@ -1401,24 +1392,6 @@ void Synth::Impl::startVoice(Region* region, int delay, const TriggerEvent& trig
     polyphonyGroups_[region->group].registerVoice(selectedVoice);
 }
 
-bool Synth::Impl::playingAttackVoice(const Region* releaseRegion) noexcept
-{
-    const auto compatibleVoice = [releaseRegion](const Voice* v) -> bool {
-        const TriggerEvent& event = v->getTriggerEvent();
-        return (
-            !v->isFree()
-            && event.type == TriggerEventType::NoteOn
-            && releaseRegion->keyRange.containsWithEnd(event.number)
-            && releaseRegion->velocityRange.containsWithEnd(event.value)
-        );
-    };
-
-    if (absl::c_find_if(voiceViewArray_, compatibleVoice) == voiceViewArray_.end())
-        return false;
-    else
-        return true;
-}
-
 void Synth::Impl::noteOffDispatch(int delay, int noteNumber, float velocity) noexcept
 {
     const auto randValue = randNoteDistribution_(Random::randomGenerator);
@@ -1433,7 +1406,7 @@ void Synth::Impl::noteOffDispatch(int delay, int noteNumber, float velocity) noe
 
     for (auto& region : noteActivationLists_[noteNumber]) {
         if (region->registerNoteOff(noteNumber, velocity, randValue)) {
-            if (region->trigger == SfzTrigger::release && !region->rtDead && !playingAttackVoice(region))
+            if (region->trigger == SfzTrigger::release && !region->rtDead && !voiceList_.playingAttackVoice(region))
                 continue;
 
             startVoice(region, delay, triggerEvent, ring);
@@ -1577,7 +1550,7 @@ void Synth::Impl::noteOnDispatch(int delay, int noteNumber, float velocity) noex
 
 void Synth::Impl::startDelayedReleaseVoices(Region* region, int delay, SisterVoiceRingBuilder& ring) noexcept
 {
-    if (!region->rtDead && !playingAttackVoice(region)) {
+    if (!region->rtDead && !voiceList_.playingAttackVoice(region)) {
         region->delayedReleases.clear();
         return;
     }
diff --git a/src/sfizz/VoiceList.h b/src/sfizz/VoiceList.h
index aae6f44f..0903c0bb 100644
--- a/src/sfizz/VoiceList.h
+++ b/src/sfizz/VoiceList.h
@@ -7,7 +7,9 @@
 #pragma once
 
 #include "Voice.h"
+#include "Region.h"
 #include <vector>
+#include <absl/algorithm/container.h>
 
 namespace sfz {
 
@@ -21,7 +23,7 @@ struct VoiceList
      */
     const Voice* getVoiceById(NumericId<Voice> id) const noexcept
     {
-        const size_t size = list.size();
+        const size_t size = list_.size();
 
         if (size == 0 || !id.valid())
             return nullptr;
@@ -30,10 +32,10 @@ struct VoiceList
         size_t index = static_cast<size_t>(id.number());
         index = std::min(index, size - 1);
 
-        while (index > 0 && list[index].getId().number() > id.number())
+        while (index > 0 && list_[index].getId().number() > id.number())
             --index;
 
-        return (list[index].getId() == id) ? &list[index] : nullptr;
+        return (list_[index].getId() == id) ? &list_[index] : nullptr;
     }
 
     Voice* getVoiceById(NumericId<Voice> id) noexcept
@@ -44,25 +46,43 @@ struct VoiceList
 
     void reset()
     {
-        for (auto& voice : list)
+        for (auto& voice : list_)
             voice.reset();
     }
 
-    typename std::vector<Voice>::iterator begin() { return list.begin(); }
-    typename std::vector<Voice>::const_iterator cbegin() const { return list.cbegin(); }
-    typename std::vector<Voice>::iterator end() { return list.end(); }
-    typename std::vector<Voice>::const_iterator cend() const { return list.cend(); }
-    typename std::vector<Voice>::reference operator[] (size_t n) { return list[n]; }
-    typename std::vector<Voice>::const_reference operator[] (size_t n) const { return list[n]; }
-    typename std::vector<Voice>::reference back() { return list.back(); }
-    typename std::vector<Voice>::const_reference back() const { return list.back(); }
-    size_t size() const { return list.size(); }
-    void clear() { list.clear(); }
-    void reserve(size_t n) { list.reserve(n); }
+    bool playingAttackVoice(const Region* releaseRegion) noexcept
+    {
+        const auto compatibleVoice = [releaseRegion](const Voice& v) -> bool {
+            const TriggerEvent& event = v.getTriggerEvent();
+            return (
+                !v.isFree()
+                && event.type == TriggerEventType::NoteOn
+                && releaseRegion->keyRange.containsWithEnd(event.number)
+                && releaseRegion->velocityRange.containsWithEnd(event.value)
+            );
+        };
+
+        if (absl::c_find_if(list_, compatibleVoice) == list_.end())
+            return false;
+        else
+            return true;
+    }
+
+    typename std::vector<Voice>::iterator begin() { return list_.begin(); }
+    typename std::vector<Voice>::const_iterator cbegin() const { return list_.cbegin(); }
+    typename std::vector<Voice>::iterator end() { return list_.end(); }
+    typename std::vector<Voice>::const_iterator cend() const { return list_.cend(); }
+    typename std::vector<Voice>::reference operator[] (size_t n) { return list_[n]; }
+    typename std::vector<Voice>::const_reference operator[] (size_t n) const { return list_[n]; }
+    typename std::vector<Voice>::reference back() { return list_.back(); }
+    typename std::vector<Voice>::const_reference back() const { return list_.back(); }
+    size_t size() const { return list_.size(); }
+    void clear() { list_.clear(); }
+    void reserve(size_t n) { list_.reserve(n); }
     template< class... Args >
-    void emplace_back(Args&&... args) { list.emplace_back(std::forward<Args>(args)...); }
+    void emplace_back(Args&&... args) { list_.emplace_back(std::forward<Args>(args)...); }
 private:
-    std::vector<Voice> list;
+    std::vector<Voice> list_;
 };
 
 } // namespace sfz