diff --git a/src/ParameterStore.cpp b/src/ParameterStore.cpp
new file mode 100644
index 0000000..b85bffc
--- /dev/null
+++ b/src/ParameterStore.cpp
@@ -0,0 +1,18 @@
+
+#include "ParameterStore.hpp"
+
+ParameterStore::ParameterStore() {
+
+}
+
+// set parameter value
+void ParameterStore::set(ParamId id, float value) {
+    Param oldParam = values_[static_cast<size_t>(id)].load(std::memory_order_relaxed);
+    Param updatedParam = { value, oldParam.min, oldParam.max };
+    values_[static_cast<size_t>(id)].store(updatedParam, std::memory_order_relaxed);
+}
+
+// get a single parameter
+float ParameterStore::get(ParamId id) const {
+    return values_[static_cast<size_t>(id)].load(std::memory_order_relaxed).val;
+}
diff --git a/src/ParameterStore.hpp b/src/ParameterStore.hpp
new file mode 100644
index 0000000..0def272
--- /dev/null
+++ b/src/ParameterStore.hpp
@@ -0,0 +1,37 @@
+
+#pragma once
+
+#include <vector>
+#include <cstdint>
+
+enum class ParamId : uint8_t {
+    MasterGain,
+    Count
+};
+
+struct Param {
+    float val;
+    float min;
+    float max;
+};
+
+constexpr size_t PARAM_COUNT = static_cast<size_t>(ParamId::Count);
+
+class ParameterStore {
+
+public:
+
+    ParameterStore();
+    ~ParameterStore() = default;
+
+    void set(ParamId id, float value);
+    void set(ParamId id, int32_t value) { set(id, static_cast<float>(value)); }
+    void set(EnvelopeId id, float depth, float a, float d, float s, float r);
+    float get(ParamId id) const;
+    int32_t getInt(ParamId id) const { return static_cast<int32_t>(get(id)); }
+
+private:
+
+    std::array<std::atomic<Param>, PARAM_COUNT> values_;
+
+};
\ No newline at end of file
diff --git a/src/synth/Instruments/PianoString.cpp b/src/synth/Instruments/PianoString.cpp
index 583ed89..79daa1a 100644
--- a/src/synth/Instruments/PianoString.cpp
+++ b/src/synth/Instruments/PianoString.cpp
@@ -13,7 +13,7 @@ PianoString::PianoString(ConfigService* config, LoggerService* logger) : Instrum
 void PianoString::noteOn(float frequency, float velocity) {
 
     active_ = true;
-    frequency_ = frequency;
+    frequency_ = frequency / 1.03746174945f; // empirical adjustment (original was 83 cents sharp)
 
     damping_ = 0.5f;
     rms_ = 5.0f;
@@ -84,9 +84,9 @@ float PianoString::process(bool& scopeTrigger) {
     }
 
     phaseTracker_ += frequency_ / sampleRate_;
-    if(phaseTracker_ > 1.0f) {
-        phaseTracker_ -= 1.0f;
-        scopeTrigger = true;
+    if(phaseTracker_ > 2.0f) {
+        phaseTracker_ -= 2.0f;
+        if(!scopeTrigger) scopeTrigger = true;
     }
 
     float sampleOut = stringY_next_[static_cast<size_t>(samplePosition_*segmentCount_)];