diff --git a/src/sfizz/modulations/ModKey.cpp b/src/sfizz/modulations/ModKey.cpp
index 5ba5e02c..c5ee2a37 100644
--- a/src/sfizz/modulations/ModKey.cpp
+++ b/src/sfizz/modulations/ModKey.cpp
@@ -5,10 +5,8 @@
 // If not, contact the sfizz maintainers at https://github.com/sfztools/sfizz
 
 #include "ModKey.h"
-#include "ModId.h"
 #include "../Debug.h"
 #include <absl/strings/str_cat.h>
-#include <cstring>
 
 namespace sfz {
 
@@ -32,16 +30,6 @@ ModKey::Parameters& ModKey::Parameters::operator=(const Parameters& other) noexc
     return *this;
 }
 
-bool ModKey::Parameters::operator==(const Parameters& other) const noexcept
-{
-    return std::memcmp(this, &other, sizeof(*this)) == 0;
-}
-
-bool ModKey::Parameters::operator!=(const Parameters& other) const noexcept
-{
-    return std::memcmp(this, &other, sizeof(*this)) != 0;
-}
-
 ModKey ModKey::createCC(uint16_t cc, uint8_t curve, uint8_t smooth, float value, float step)
 {
     ModKey::Parameters p;
@@ -74,10 +62,6 @@ bool ModKey::isTarget() const noexcept
     return ModIds::isTarget(id_);
 }
 
-int ModKey::flags() const noexcept
-{
-    return ModIds::flags(id_);
-}
 
 std::string ModKey::toString() const
 {
@@ -111,13 +95,3 @@ std::string ModKey::toString() const
 
 } // namespace sfz
 
-bool sfz::ModKey::operator==(const ModKey &other) const noexcept
-{
-    return id_ == other.id_ && region_ == other.region_ &&
-        parameters() == other.parameters();
-}
-
-bool sfz::ModKey::operator!=(const ModKey &other) const noexcept
-{
-    return !this->operator==(other);
-}
diff --git a/src/sfizz/modulations/ModKey.h b/src/sfizz/modulations/ModKey.h
index 37b8b072..5fff0197 100644
--- a/src/sfizz/modulations/ModKey.h
+++ b/src/sfizz/modulations/ModKey.h
@@ -6,8 +6,10 @@
 
 #pragma once
 #include "ModKeyHash.h"
+#include "ModId.h"
 #include "../NumericId.h"
 #include <string>
+#include <cstring>
 
 namespace sfz {
 
@@ -24,7 +26,7 @@ public:
 
     ModKey() = default;
     explicit ModKey(ModId id, NumericId<Region> region = {}, Parameters params = {})
-        : id_(id), region_(region), params_(params) {}
+        : id_(id), region_(region), params_(params), flags_(ModIds::flags(id_)) {}
 
     static ModKey createCC(uint16_t cc, uint8_t curve, uint8_t smooth, float value, float step);
     static ModKey createNXYZ(ModId id, NumericId<Region> region, uint8_t N = 0, uint8_t X = 0, uint8_t Y = 0, uint8_t Z = 0);
@@ -34,10 +36,10 @@ public:
     const ModId& id() const noexcept { return id_; }
     NumericId<Region> region() const noexcept { return region_; }
     const Parameters& parameters() const noexcept { return params_; }
+    int flags() const noexcept { return flags_; }
 
     bool isSource() const noexcept;
     bool isTarget() const noexcept;
-    int flags() const noexcept;
     std::string toString() const;
 
     struct Parameters {
@@ -48,8 +50,15 @@ public:
         Parameters(Parameters&&) = delete;
         Parameters &operator=(Parameters&&) = delete;
 
-        bool operator==(const Parameters& other) const noexcept;
-        bool operator!=(const Parameters& other) const noexcept;
+        bool operator==(const Parameters& other) const noexcept
+        {
+            return std::memcmp(this, &other, sizeof(*this)) == 0;
+        }
+
+        bool operator!=(const Parameters& other) const noexcept
+        {
+            return std::memcmp(this, &other, sizeof(*this)) != 0;
+        }
 
         union {
             //! Parameters if this key identifies a CC source
@@ -63,8 +72,17 @@ public:
     };
 
 public:
-    bool operator==(const ModKey &other) const noexcept;
-    bool operator!=(const ModKey &other) const noexcept;
+    bool operator==(const ModKey &other) const noexcept
+    {
+        return id_ == other.id_ && region_ == other.region_ &&
+            parameters() == other.parameters();
+    }
+
+    bool operator!=(const ModKey &other) const noexcept
+    {
+        return !this->operator==(other);
+    }
+
 
 private:
     //! Identifier
@@ -73,6 +91,8 @@ private:
     NumericId<Region> region_;
     //! List of values which identify the key uniquely, along with the hash and region
     Parameters params_ {};
+    // Memorize the flag
+    int flags_;
 };
 
 } // namespace sfz
diff --git a/src/sfizz/modulations/ModMatrix.cpp b/src/sfizz/modulations/ModMatrix.cpp
index 9290ba2d..643f168d 100644
--- a/src/sfizz/modulations/ModMatrix.cpp
+++ b/src/sfizz/modulations/ModMatrix.cpp
@@ -364,8 +364,7 @@ float* ModMatrix::getModulation(TargetId targetId)
                 }
                 else {
                     ASSERT(targetFlags & kModIsAdditive);
-                    for (uint32_t i = 0; i < numFrames; ++i)
-                        buffer[i] += sourceDepth * sourceBuffer[i];
+                    sfz::multiplyAdd1<float>(sourceDepth, sourceBuffer, buffer);
                 }
             }
         }