diff --git a/src/sfizz/PolyphonyGroup.h b/src/sfizz/PolyphonyGroup.h
new file mode 100644
index 000000000..8f6a8c409
--- /dev/null
+++ b/src/sfizz/PolyphonyGroup.h
@@ -0,0 +1,40 @@
+#pragma once
+#include "Region.h"
+#include "Voice.h"
+#include "absl/algorithm/container.h"
+
+namespace sfz
+{
+class PolyphonyGroup {
+public:
+    void setPolyphonyLimit(unsigned limit)
+    {
+        polyphonyLimit = limit;
+        voices.reserve(limit);
+    }
+    unsigned getPolyphonyLimit() const { return polyphonyLimit; }
+    void registerVoice(Voice* voice)
+    {
+        if (absl::c_find(voices, voice) == voices.end())
+            voices.push_back(voice);
+    }
+    void removeVoice(const Voice* voice)
+    {
+        auto it = absl::c_find(voices, voice);
+        if (it == voices.end())
+            return;
+
+        auto last = voices.end() - 1;
+        if (it != last)
+            std::iter_swap(it, last);
+
+        voices.pop_back();
+    }
+    const std::vector<Voice*>& getActiveVoices() const { return voices; }
+    std::vector<Voice*>& getActiveVoices() { return voices; }
+private:
+    unsigned polyphonyLimit { config::maxVoices };
+    std::vector<Voice*> voices;
+};
+
+}
diff --git a/src/sfizz/Region.cpp b/src/sfizz/Region.cpp
index e772b734c..5d33d5ab3 100644
--- a/src/sfizz/Region.cpp
+++ b/src/sfizz/Region.cpp
@@ -158,6 +158,10 @@ bool sfz::Region::parseOpcode(const Opcode& rawOpcode)
             DBG("Unkown off mode:" << std::string(opcode.value));
         }
         break;
+    case hash("polyphony"):
+        if (auto value = readOpcode(opcode.value, Default::polyphonyRange))
+            polyphony = *value;
+        break;
     case hash("note_polyphony"):
         if (auto value = readOpcode(opcode.value, Default::polyphonyRange))
             notePolyphony = *value;
diff --git a/src/sfizz/Region.h b/src/sfizz/Region.h
index e363116b0..b5bf56f46 100644
--- a/src/sfizz/Region.h
+++ b/src/sfizz/Region.h
@@ -23,6 +23,9 @@
 #include <vector>
 
 namespace sfz {
+
+class RegionSet;
+
 /**
  * @brief Regions are the basic building blocks for the SFZ parsing and handling code.
  * All SFZ files are made of regions that are activated when a key is pressed or a CC
@@ -272,7 +275,8 @@ struct Region {
     uint32_t group { Default::group }; // group
     absl::optional<uint32_t> offBy {}; // off_by
     SfzOffMode offMode { Default::offMode }; // off_mode
-    absl::optional<uint32_t> notePolyphony {};
+    absl::optional<uint32_t> notePolyphony {}; // note_polyphony
+    unsigned polyphony { config::maxVoices }; // polyphony
     SfzSelfMask selfMask { Default::selfMask };
 
     // Region logic: key mapping
@@ -357,6 +361,8 @@ struct Region {
     // Effects
     std::vector<float> gainToEffect;
 
+    // Parent
+    RegionSet* parent { nullptr };
 private:
     const MidiState& midiState;
     bool keySwitched { true };
diff --git a/src/sfizz/RegionSet.h b/src/sfizz/RegionSet.h
new file mode 100644
index 000000000..539e3eca4
--- /dev/null
+++ b/src/sfizz/RegionSet.h
@@ -0,0 +1,74 @@
+#pragma once
+#include "Region.h"
+#include "Voice.h"
+#include <vector>
+
+namespace sfz
+{
+
+class RegionSet {
+public:
+    void setPolyphonyLimit(unsigned limit)
+    {
+        polyphonyLimit = limit;
+        voices.reserve(limit);
+    }
+    unsigned getPolyphonyLimit() const { return polyphonyLimit; }
+    void addRegion(Region* region)
+    {
+        if (absl::c_find(regions, region) == regions.end())
+            regions.push_back(region);
+    }
+    void addSubset(RegionSet* group)
+    {
+        if (absl::c_find(subsets, group) == subsets.end())
+            subsets.push_back(group);
+    }
+    void registerVoice(Voice* voice)
+    {
+        if (absl::c_find(voices, voice) == voices.end())
+            voices.push_back(voice);
+    }
+    void removeVoice(const Voice* voice)
+    {
+        auto it = absl::c_find(voices, voice);
+        if (it == voices.end())
+            return;
+
+        auto last = voices.end() - 1;
+        if (it != last)
+            std::iter_swap(it, last);
+
+        voices.pop_back();
+        DBG("Active voices size " << voices.size());
+    }
+    static void registerVoiceInHierarchy(const Region* region, Voice* voice)
+    {
+        auto parent = region->parent;
+        while (parent != nullptr) {
+            parent->registerVoice(voice);
+            parent = parent->getParent();
+        }
+    }
+    static void removeVoiceFromHierarchy(const Region* region, const Voice* voice)
+    {
+        auto parent = region->parent;
+        while (parent != nullptr) {
+            parent->removeVoice(voice);
+            parent = parent->getParent();
+        }
+    }
+    RegionSet* getParent() const { return parent; }
+    void setParent(RegionSet* parent) { this->parent = parent; }
+    const std::vector<Voice*>& getActiveVoices() const { return voices; }
+    const std::vector<Region*>& getRegions() const { return regions; }
+    const std::vector<RegionSet*>& getSubsets() const { return subsets; }
+private:
+    RegionSet* parent { nullptr };
+    std::vector<Region*> regions;
+    std::vector<RegionSet*> subsets;
+    std::vector<Voice*> voices;
+    unsigned polyphonyLimit { config::maxVoices };
+};
+
+}
diff --git a/src/sfizz/Synth.cpp b/src/sfizz/Synth.cpp
index 5fa4827b3..be9e173bf 100644
--- a/src/sfizz/Synth.cpp
+++ b/src/sfizz/Synth.cpp
@@ -49,14 +49,31 @@ void sfz::Synth::onVoiceStateChanged(NumericId<Voice> id, Voice::State state)
 {
     (void)id;
     (void)state;
-    DBG("Voice " << id.number << ": state " << static_cast<int>(state));
+    if (state == Voice::State::idle) {
+        auto voice = getVoiceById(id);
+        DBG("Removing voice " << id.number << " from hierarchies");
+        RegionSet::removeVoiceFromHierarchy(voice->getRegion(), voice);
+        polyphonyGroups[voice->getRegion()->group].removeVoice(voice);
+    }
+
 }
 
 void sfz::Synth::onParseFullBlock(const std::string& header, const std::vector<Opcode>& members)
 {
+    const auto newRegionSet = [&](RegionSet* parentSet) {
+        ASSERT(parentSet != nullptr);
+        sets.emplace_back(new RegionSet);
+        auto newSet = sets.back().get();
+        parentSet->addSubset(newSet);
+        newSet->setParent(parentSet);
+        currentSet = newSet;
+    };
+
     switch (hash(header)) {
     case hash("global"):
         globalOpcodes = members;
+        currentSet = sets.front().get();
+        lastHeader = Header::Global;
         groupOpcodes.clear();
         masterOpcodes.clear();
         handleGlobalOpcodes(members);
@@ -67,11 +84,19 @@ void sfz::Synth::onParseFullBlock(const std::string& header, const std::vector<O
         break;
     case hash("master"):
         masterOpcodes = members;
+        newRegionSet(sets.front().get());
         groupOpcodes.clear();
+        lastHeader = Header::Master;
+        handleMasterOpcodes(members);
         numMasters++;
         break;
     case hash("group"):
         groupOpcodes = members;
+        if (lastHeader == Header::Group)
+            newRegionSet(currentSet->getParent());
+        else
+            newRegionSet(currentSet);
+        lastHeader = Header::Group;
         handleGroupOpcodes(members, masterOpcodes);
         numGroups++;
         break;
@@ -103,6 +128,8 @@ void sfz::Synth::onParseWarning(const SourceRange& range, const std::string& mes
 
 void sfz::Synth::buildRegion(const std::vector<Opcode>& regionOpcodes)
 {
+    ASSERT(currentSet != nullptr);
+
     int regionNumber = static_cast<int>(regions.size());
     auto lastRegion = absl::make_unique<Region>(regionNumber, resources.midiState, defaultPath);
 
@@ -126,6 +153,13 @@ void sfz::Synth::buildRegion(const std::vector<Opcode>& regionOpcodes)
     if (octaveOffset != 0 || noteOffset != 0)
         lastRegion->offsetAllKeys(octaveOffset * 12 + noteOffset);
 
+    // There was a combination of group= and polyphony= on a region, so set the group polyphony
+    if (lastRegion->group != Default::group && lastRegion->polyphony != config::maxVoices)
+        setGroupPolyphony(lastRegion->group, lastRegion->polyphony);
+
+    lastRegion->parent = currentSet;
+    currentSet->addRegion(lastRegion.get());
+
     regions.push_back(std::move(lastRegion));
 }
 
@@ -140,6 +174,9 @@ void sfz::Synth::clear()
     for (auto& list : ccActivationLists)
         list.clear();
 
+    sets.clear();
+    sets.emplace_back(new RegionSet);
+    currentSet = sets.front().get();
     regions.clear();
     effectBuses.clear();
     effectBuses.emplace_back(new EffectBus);
@@ -160,17 +197,38 @@ void sfz::Synth::clear()
     masterOpcodes.clear();
     groupOpcodes.clear();
     unknownOpcodes.clear();
-    groupMaxPolyphony.clear();
-    groupMaxPolyphony.push_back(config::maxVoices);
+    polyphonyGroups.clear();
+    polyphonyGroups.emplace_back();
+    polyphonyGroups.back().setPolyphonyLimit(config::maxVoices);
     modificationTime = fs::file_time_type::min();
 }
 
+void sfz::Synth::handleMasterOpcodes(const std::vector<Opcode>& members)
+{
+    for (auto& rawMember : members) {
+        const Opcode member = rawMember.cleanUp(kOpcodeScopeGlobal);
+
+        switch (member.lettersOnlyHash) {
+        case hash("polyphony"):
+            ASSERT(currentSet != nullptr);
+            if (auto value = readOpcode(member.value, Default::polyphonyRange))
+                currentSet->setPolyphonyLimit(*value);
+            break;
+        }
+    }
+}
+
 void sfz::Synth::handleGlobalOpcodes(const std::vector<Opcode>& members)
 {
     for (auto& rawMember : members) {
         const Opcode member = rawMember.cleanUp(kOpcodeScopeGlobal);
 
         switch (member.lettersOnlyHash) {
+        case hash("polyphony"):
+            ASSERT(currentSet != nullptr);
+            if (auto value = readOpcode(member.value, Default::polyphonyRange))
+                currentSet->setPolyphonyLimit(*value);
+            break;
         case hash("sw_default"):
             setValueFromOpcode(member, defaultSwitch, Default::keyRange);
             break;
@@ -185,7 +243,7 @@ void sfz::Synth::handleGlobalOpcodes(const std::vector<Opcode>& members)
 void sfz::Synth::handleGroupOpcodes(const std::vector<Opcode>& members, const std::vector<Opcode>& masterMembers)
 {
     absl::optional<unsigned> groupIdx;
-    unsigned maxPolyphony { config::maxVoices };
+    absl::optional<unsigned> maxPolyphony;
 
     const auto parseOpcode = [&](const Opcode& rawMember) {
         const Opcode member = rawMember.cleanUp(kOpcodeScopeGroup);
@@ -195,7 +253,7 @@ void sfz::Synth::handleGroupOpcodes(const std::vector<Opcode>& members, const st
             setValueFromOpcode(member, groupIdx, Default::groupRange);
             break;
         case hash("polyphony"):
-            setValueFromOpcode(member, maxPolyphony, Range<unsigned>(0, config::maxVoices));
+            setValueFromOpcode(member, maxPolyphony, Default::polyphonyRange);
             break;
         }
     };
@@ -206,8 +264,14 @@ void sfz::Synth::handleGroupOpcodes(const std::vector<Opcode>& members, const st
     for (auto& member : members)
         parseOpcode(member);
 
-    if (groupIdx)
-        setGroupPolyphony(*groupIdx, maxPolyphony);
+    if (groupIdx && maxPolyphony) {
+        setGroupPolyphony(*groupIdx, *maxPolyphony);
+    } else if (maxPolyphony) {
+        ASSERT(currentSet != nullptr);
+        currentSet->setPolyphonyLimit(*maxPolyphony);
+    } else if (groupIdx && *groupIdx > polyphonyGroups.size()) {
+        setGroupPolyphony(*groupIdx, config::maxVoices);
+    }
 }
 
 void sfz::Synth::handleControlOpcodes(const std::vector<Opcode>& members)
@@ -434,8 +498,10 @@ void sfz::Synth::finalizeSfzLoad()
             keyswitchLabels.push_back({ *region->keyswitch, *region->keyswitchLabel });
 
         // Some regions had group number but no "group-level" opcodes handled the polyphony
-        while (groupMaxPolyphony.size() <= region->group)
-            groupMaxPolyphony.push_back(config::maxVoices);
+        while (polyphonyGroups.size() <= region->group) {
+            polyphonyGroups.emplace_back();
+            polyphonyGroups.back().setPolyphonyLimit(config::maxVoices);
+        }
 
         for (auto note = 0; note < 128; note++) {
             if (region->keyRange.containsWithEnd(note) || (region->hasKeyswitches() && region->keyswitchRange.containsWithEnd(note)))
@@ -803,6 +869,8 @@ void sfz::Synth::noteOffDispatch(int delay, int noteNumber, float velocity) noex
 
             voice->startVoice(region, delay, noteNumber, velocity, Voice::TriggerType::NoteOff);
             ring.addVoiceToRing(voice);
+            RegionSet::registerVoiceInHierarchy(region, voice);
+            polyphonyGroups[region->group].registerVoice(voice);
         }
     }
 }
@@ -814,8 +882,8 @@ void sfz::Synth::noteOnDispatch(int delay, int noteNumber, float velocity) noexc
 
     for (auto& region : noteActivationLists[noteNumber]) {
         if (region->registerNoteOn(noteNumber, velocity, randValue)) {
-            unsigned activeNotesInGroup { 0 };
-            unsigned activeNotes { 0 };
+            unsigned notePolyphonyCounter { 0 };
+            unsigned regionPolyphonyCounter { 0 };
             Voice* selfMaskCandidate { nullptr };
 
             for (auto& voice : voices) {
@@ -823,12 +891,12 @@ void sfz::Synth::noteOnDispatch(int delay, int noteNumber, float velocity) noexc
                 if (voiceRegion == nullptr)
                     continue;
 
-                if (voiceRegion->group == region->group)
-                    activeNotesInGroup += 1;
+                if (voiceRegion == region)
+                    regionPolyphonyCounter += 1;
 
                 if (region->notePolyphony) {
                     if (voice->getTriggerNumber() == noteNumber && voice->getTriggerType() == Voice::TriggerType::NoteOn) {
-                        activeNotes += 1;
+                        notePolyphonyCounter += 1;
                         switch (region->selfMask) {
                         case SfzSelfMask::mask:
                             if (voice->getTriggerValue() < velocity) {
@@ -848,10 +916,30 @@ void sfz::Synth::noteOnDispatch(int delay, int noteNumber, float velocity) noexc
                     noteOffDispatch(delay, voice->getTriggerNumber(), voice->getTriggerValue());
             }
 
-            if (activeNotesInGroup >= groupMaxPolyphony[region->group])
+            // FIXME: Do something for the polyphony limit
+            if (polyphonyGroups[region->group].getActiveVoices().size()
+                == polyphonyGroups[region->group].getPolyphonyLimit())
+                continue;
+
+            // FIXME: Do something for the polyphony limit
+            if (regionPolyphonyCounter >= region->polyphony)
                 continue;
 
-            if (region->notePolyphony && activeNotes >= *region->notePolyphony) {
+            // FIXME: Do something for the polyphony limit
+            auto parent = region->parent;
+            bool polyphonyReached { false };
+            while (parent != nullptr) {
+                if (parent->getActiveVoices().size() >= parent->getPolyphonyLimit()) {
+                    polyphonyReached = true;
+                    break;
+                }
+
+                parent = parent->getParent();
+            }
+            if (polyphonyReached)
+                continue;
+
+            if (region->notePolyphony && notePolyphonyCounter >= *region->notePolyphony) {
                 if (selfMaskCandidate != nullptr)
                     selfMaskCandidate->release(delay);
                 else // We're the lowest velocity guy here
@@ -864,6 +952,8 @@ void sfz::Synth::noteOnDispatch(int delay, int noteNumber, float velocity) noexc
 
             voice->startVoice(region, delay, noteNumber, velocity, Voice::TriggerType::NoteOn);
             ring.addVoiceToRing(voice);
+            RegionSet::registerVoiceInHierarchy(region, voice);
+            polyphonyGroups[region->group].registerVoice(voice);
         }
     }
 }
@@ -911,6 +1001,8 @@ void sfz::Synth::hdcc(int delay, int ccNumber, float normValue) noexcept
 
             voice->startVoice(region, delay, ccNumber, normValue, Voice::TriggerType::CC);
             ring.addVoiceToRing(voice);
+            RegionSet::registerVoiceInHierarchy(region, voice);
+            polyphonyGroups[region->group].registerVoice(voice);
         }
     }
 }
@@ -1073,6 +1165,16 @@ const sfz::EffectBus* sfz::Synth::getEffectBusView(int idx) const noexcept
     return (size_t)idx < effectBuses.size() ? effectBuses[idx].get() : nullptr;
 }
 
+const sfz::RegionSet* sfz::Synth::getRegionSetView(int idx) const noexcept
+{
+    return (size_t)idx < sets.size() ? sets[idx].get() : nullptr;
+}
+
+const sfz::PolyphonyGroup* sfz::Synth::getPolyphonyGroupView(int idx) const noexcept
+{
+    return (size_t)idx < polyphonyGroups.size() ? &polyphonyGroups[idx] : nullptr;
+}
+
 const sfz::Region* sfz::Synth::getRegionById(NumericId<Region> id) const noexcept
 {
     const size_t size = regions.size();
@@ -1112,6 +1214,11 @@ const sfz::Voice* sfz::Synth::getVoiceView(int idx) const noexcept
     return (size_t)idx < voices.size() ? voices[idx].get() : nullptr;
 }
 
+unsigned sfz::Synth::getNumPolyphonyGroups() const noexcept
+{
+    return polyphonyGroups.size();
+}
+
 const std::vector<std::string>& sfz::Synth::getUnknownOpcodes() const noexcept
 {
     return unknownOpcodes;
@@ -1209,8 +1316,10 @@ void sfz::Synth::setOversamplingFactor(sfz::Oversampling factor) noexcept
     if (factor == oversamplingFactor)
         return;
 
-    for (auto& voice : voices)
+    for (auto& voice : voices) {
+
         voice->reset();
+    }
 
     resources.filePool.emptyFileLoadingQueues();
     resources.filePool.setOversamplingFactor(factor);
@@ -1322,8 +1431,8 @@ void sfz::Synth::allSoundOff() noexcept
 
 void sfz::Synth::setGroupPolyphony(unsigned groupIdx, unsigned polyphony) noexcept
 {
-    while (groupMaxPolyphony.size() <= groupIdx)
-        groupMaxPolyphony.push_back(config::maxVoices);
+    while (polyphonyGroups.size() <= groupIdx)
+        polyphonyGroups.emplace_back();
 
-    groupMaxPolyphony[groupIdx] = polyphony;
+    polyphonyGroups[groupIdx].setPolyphonyLimit(polyphony);
 }
diff --git a/src/sfizz/Synth.h b/src/sfizz/Synth.h
index 00372288b..9dcfd0790 100644
--- a/src/sfizz/Synth.h
+++ b/src/sfizz/Synth.h
@@ -9,6 +9,8 @@
 #include "Parser.h"
 #include "Voice.h"
 #include "Region.h"
+#include "RegionSet.h"
+#include "PolyphonyGroup.h"
 #include "Effects.h"
 #include "LeakDetector.h"
 #include "MidiState.h"
@@ -220,17 +222,39 @@ class Synth final : public Voice::StateListener, public Parser::Listener {
      * for testing.
      *
      * @param idx
-     * @return const Region*
+     * @return const Voice*
      */
     const Voice* getVoiceView(int idx) const noexcept;
     /**
-     * @brief Get a raw view into a specific voice. This is mostly used
+     * @brief Get a raw view into a specific effect bus. This is mostly used
      * for testing.
      *
      * @param idx
-     * @return const Region*
+     * @return const EffectBus*
      */
     const EffectBus* getEffectBusView(int idx) const noexcept;
+    /**
+     * @brief Get a raw view into a specific set of regions. This is mostly used
+     * for testing.
+     *
+     * @param idx
+     * @return const RegionSet*
+     */
+    const RegionSet* getRegionSetView(int idx) const noexcept;
+    /**
+     * @brief Get a raw view into a specific polyphony group. This is mostly used
+     * for testing.
+     *
+     * @param idx
+     * @return const PolyphonyGroup*
+     */
+    const PolyphonyGroup* getPolyphonyGroupView(int idx) const noexcept;
+    /**
+     * @brief Get the number of polyphony groups
+     *
+     * @return unsigned
+     */
+    unsigned getNumPolyphonyGroups() const noexcept;
     /**
      * @brief Get a list of unknown opcodes. The lifetime of the
      * string views in the code are linked to the currently loaded
@@ -572,7 +596,6 @@ class Synth final : public Voice::StateListener, public Parser::Listener {
      * @param polyphone the max polyphony
      */
     void setGroupPolyphony(unsigned groupIdx, unsigned polyphony) noexcept;
-    std::vector<unsigned> groupMaxPolyphony { config::maxVoices };
 
     /**
      * @brief Reset all CCs; to be used on CC 121
@@ -598,6 +621,12 @@ class Synth final : public Voice::StateListener, public Parser::Listener {
      * @param members the opcodes of the <global> block
      */
     void handleGlobalOpcodes(const std::vector<Opcode>& members);
+    /**
+     * @brief Helper function to dispatch <master> opcodes
+     *
+     * @param members the opcodes of the <master> block
+     */
+    void handleMasterOpcodes(const std::vector<Opcode>& members);
     /**
      * @brief Helper function to dispatch <group> opcodes
      *
@@ -645,8 +674,6 @@ class Synth final : public Voice::StateListener, public Parser::Listener {
     void noteOnDispatch(int delay, int noteNumber, float velocity) noexcept;
     void noteOffDispatch(int delay, int noteNumber, float velocity) noexcept;
 
-    unsigned killSisterVoices(const Voice* voiceToKill) noexcept;
-
     // Opcode memory; these are used to build regions, as a new region
     // will integrate opcodes from the group, master and global block
     std::vector<Opcode> globalOpcodes;
@@ -668,15 +695,25 @@ class Synth final : public Voice::StateListener, public Parser::Listener {
     // Default active switch if multiple keyswitchable regions are present
     absl::optional<uint8_t> defaultSwitch;
     std::vector<std::string> unknownOpcodes;
-    using RegionPtrVector = std::vector<Region*>;
-    using VoicePtrVector = std::vector<Voice*>;
-    std::vector<std::unique_ptr<Region>> regions;
-    std::vector<std::unique_ptr<Voice>> voices;
+    using RegionViewVector = std::vector<Region*>;
+    using VoiceViewVector = std::vector<Voice*>;
+    using VoicePtr = std::unique_ptr<Voice>;
+    using RegionPtr = std::unique_ptr<Region>;
+    using RegionSetPtr = std::unique_ptr<RegionSet>;
+    std::vector<RegionPtr> regions;
+    std::vector<VoicePtr> voices;
+    // These are more general "groups" than sfz and encapsulates the full hierarchy
+    enum class Header { Global, Master, Group };
+    RegionSet* currentSet;
+    Header lastHeader { Header::Global };
+    std::vector<RegionSetPtr> sets;
+    // These are the `group=` groups where you can off voices
+    std::vector<PolyphonyGroup> polyphonyGroups;
     // Views to speed up iteration over the regions and voices when events
     // occur in the audio callback
-    VoicePtrVector voiceViewArray;
-    std::array<RegionPtrVector, 128> noteActivationLists;
-    std::array<RegionPtrVector, config::numCCs> ccActivationLists;
+    VoiceViewVector voiceViewArray;
+    std::array<RegionViewVector, 128> noteActivationLists;
+    std::array<RegionViewVector, config::numCCs> ccActivationLists;
 
     // Effect factory and buses
     EffectFactory effectFactory;
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index c71cee5b5..00e0cf874 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -18,6 +18,7 @@ set(SFIZZ_TEST_SOURCES
     MidiStateT.cpp
     OnePoleFilterT.cpp
     InterpolatorsT.cpp
+    PolyphonyT.cpp
     RegionActivationT.cpp
     RegionValueComputationsT.cpp
     # If we're tweaking the curves this kind of tests does not make sense
diff --git a/tests/PolyphonyT.cpp b/tests/PolyphonyT.cpp
new file mode 100644
index 000000000..815b6c23d
--- /dev/null
+++ b/tests/PolyphonyT.cpp
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: BSD-2-Clause
+
+// This code is part of the sfizz library and is licensed under a BSD 2-clause
+// license. You should have receive a LICENSE.md file along with the code.
+// If not, contact the sfizz maintainers at https://github.com/sfztools/sfizz
+
+#include "sfizz/Synth.h"
+#include "sfizz/SfzHelpers.h"
+#include "catch2/catch.hpp"
+
+using namespace Catch::literals;
+using namespace sfz::literals;
+
+constexpr int blockSize { 256 };
+
+
+TEST_CASE("[Polyphony] Polyphony in hierarchy")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path(), R"(
+        <region> key=61 sample=*sine polyphony=2
+        <group> polyphony=2
+        <region> key=62 sample=*sine
+        <master> polyphony=3
+        <region> key=63 sample=*sine
+        <region> key=63 sample=*sine
+        <region> key=63 sample=*sine
+        <group> polyphony=4
+        <region> key=64 sample=*sine polyphony=5
+        <region> key=64 sample=*sine
+        <region> key=64 sample=*sine
+        <region> key=64 sample=*sine
+    )");
+    REQUIRE( synth.getRegionView(0)->polyphony == 2 );
+    REQUIRE( synth.getRegionSetView(1)->getPolyphonyLimit() == 2 );
+    REQUIRE( synth.getRegionView(1)->polyphony == 2 );
+    REQUIRE( synth.getRegionSetView(2)->getPolyphonyLimit() == 3 );
+    REQUIRE( synth.getRegionSetView(2)->getRegions()[0]->polyphony == 3 );
+    REQUIRE( synth.getRegionSetView(3)->getPolyphonyLimit() == 4 );
+    REQUIRE( synth.getRegionSetView(3)->getRegions()[0]->polyphony == 5 );
+    REQUIRE( synth.getRegionSetView(3)->getRegions()[1]->polyphony == 4 );
+}
+
+TEST_CASE("[Polyphony] Polyphony groups")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path(), R"(
+        <group> polyphony=2
+        <region> key=62 sample=*sine
+        <group> group=1 polyphony=3
+        <region> key=63 sample=*sine
+        <region> key=63 sample=*sine group=2 polyphony=4
+        <region> key=63 sample=*sine group=4 polyphony=5
+        <group> group=4
+        <region> key=62 sample=*sine
+    )");
+    REQUIRE( synth.getNumPolyphonyGroups() == 5 );
+    REQUIRE( synth.getNumRegions() == 5 );
+    REQUIRE( synth.getRegionView(0)->group == 0 );
+    REQUIRE( synth.getRegionView(1)->group == 1 );
+    REQUIRE( synth.getRegionView(2)->group == 2 );
+    REQUIRE( synth.getRegionView(3)->group == 4 );
+    REQUIRE( synth.getRegionView(3)->polyphony == 5 );
+    REQUIRE( synth.getRegionView(4)->group == 4 );
+    REQUIRE( synth.getPolyphonyGroupView(1)->getPolyphonyLimit() == 3 );
+    REQUIRE( synth.getPolyphonyGroupView(2)->getPolyphonyLimit() == 4 );
+    REQUIRE( synth.getPolyphonyGroupView(3)->getPolyphonyLimit() == sfz::config::maxVoices );
+    REQUIRE( synth.getPolyphonyGroupView(4)->getPolyphonyLimit() == 5 );
+}
+
+TEST_CASE("[Polyphony] group polyphony limits")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path(), R"(
+        <group> group=1 polyphony=2
+        <region> sample=*sine key=65
+    )");
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    REQUIRE(synth.getNumActiveVoices() == 2); // group polyphony should block the last note
+}
+
+TEST_CASE("[Polyphony] Hierarchy polyphony limits")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path(), R"(
+        <group> polyphony=2
+        <region> sample=*sine key=65
+    )");
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    REQUIRE(synth.getNumActiveVoices() == 2);
+}
+
+TEST_CASE("[Polyphony] Hierarchy polyphony limits (group)")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path(), R"(
+        <group> polyphony=2
+        <region> sample=*sine key=65
+    )");
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    REQUIRE(synth.getNumActiveVoices() == 2);
+}
+
+TEST_CASE("[Polyphony] Hierarchy polyphony limits (master)")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path(), R"(
+        <master> polyphony=2
+        <group> polyphony=5
+        <region> sample=*sine key=65
+    )");
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    REQUIRE(synth.getNumActiveVoices() == 2);
+}
+
+TEST_CASE("[Polyphony] Hierarchy polyphony limits (limit in another master)")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path(), R"(
+        <master> polyphony=2
+        <region> sample=*saw key=65
+        <master>
+        <group> polyphony=5
+        <region> sample=*sine key=65
+    )");
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    REQUIRE(synth.getNumActiveVoices() == 5);
+}
+
+TEST_CASE("[Polyphony] Hierarchy polyphony limits (global)")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path(), R"(
+        <global> polyphony=2
+        <group> polyphony=5
+        <region> sample=*sine key=65
+    )");
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    REQUIRE(synth.getNumActiveVoices() == 2);
+}
+
+TEST_CASE("[Polyphony] Polyphony in master")
+{
+    sfz::Synth synth;
+    synth.setSamplesPerBlock(blockSize);
+    sfz::AudioBuffer<float> buffer { 2, blockSize };
+    synth.loadSfzString(fs::current_path(), R"(
+        <master> polyphony=2
+        <group> group=2
+        <region> sample=*sine key=65
+        <group> group=3
+        <region> sample=*sine key=63
+        <master> // Empty master resets the polyphony
+        <region> sample=*sine key=61
+    )");
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    synth.noteOn(0, 65, 64);
+    REQUIRE(synth.getNumActiveVoices() == 2); // group polyphony should block the last note
+    synth.allSoundOff();
+    synth.renderBlock(buffer);
+    REQUIRE(synth.getNumActiveVoices() == 0);
+    synth.noteOn(0, 63, 64);
+    synth.noteOn(0, 63, 64);
+    synth.noteOn(0, 63, 64);
+    REQUIRE(synth.getNumActiveVoices() == 2); // group polyphony should block the last note
+    synth.allSoundOff();
+    synth.renderBlock(buffer);
+    REQUIRE(synth.getNumActiveVoices() == 0);
+    synth.noteOn(0, 61, 64);
+    synth.noteOn(0, 61, 64);
+    synth.noteOn(0, 61, 64);
+    REQUIRE(synth.getNumActiveVoices() == 3);
+}
+
+
+TEST_CASE("[Polyphony] Self-masking")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path(), R"(
+        <region> sample=*sine key=64 note_polyphony=2
+    )");
+    synth.noteOn(0, 64, 63);
+    synth.noteOn(0, 64, 62);
+    synth.noteOn(0, 64, 64);
+    REQUIRE(synth.getNumActiveVoices() == 3); // One of these is releasing
+    REQUIRE(synth.getVoiceView(0)->getTriggerValue() == 63_norm);
+    REQUIRE(!synth.getVoiceView(0)->releasedOrFree());
+    REQUIRE(synth.getVoiceView(1)->getTriggerValue() == 62_norm);
+    REQUIRE(synth.getVoiceView(1)->releasedOrFree()); // The lowest velocity voice is the masking candidate
+    REQUIRE(synth.getVoiceView(2)->getTriggerValue() == 64_norm);
+    REQUIRE(!synth.getVoiceView(2)->releasedOrFree());
+}
+
+TEST_CASE("[Polyphony] Not self-masking")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path(), R"(
+        <region> sample=*sine key=66 note_polyphony=2 note_selfmask=off
+    )");
+    synth.noteOn(0, 66, 63);
+    synth.noteOn(0, 66, 62);
+    synth.noteOn(0, 66, 64);
+    REQUIRE(synth.getNumActiveVoices() == 3); // One of these is releasing
+    REQUIRE(synth.getVoiceView(0)->getTriggerValue() == 63_norm);
+    REQUIRE(synth.getVoiceView(0)->releasedOrFree()); // The first encountered voice is the masking candidate
+    REQUIRE(synth.getVoiceView(1)->getTriggerValue() == 62_norm);
+    REQUIRE(!synth.getVoiceView(1)->releasedOrFree());
+    REQUIRE(synth.getVoiceView(2)->getTriggerValue() == 64_norm);
+    REQUIRE(!synth.getVoiceView(2)->releasedOrFree());
+}