diff --git a/synth/midi_synth.h b/synth/midi_synth.h
index 030a6c1..9329e65 100644
--- a/synth/midi_synth.h
+++ b/synth/midi_synth.h
@@ -11,7 +11,8 @@ template <typename t_voice>
 class midi_synth : public voice_allocator<t_voice> {
 public:
     midi_synth(int _n_voices, double _samplerate, int _block_size)
-        : m_samplerate { _samplerate }
+        : voice_allocator<t_voice> { _samplerate }
+        , m_samplerate { _samplerate }
         , m_block_size { _block_size }
         , m_voices_active { false }
     {
@@ -58,13 +59,12 @@ public:
                 start_index += block_size;
             }
 
-            voices_active = voice_allocator::voices_active();
+            m_voices_active = voice_allocator::voices_active();
 
             flush_event_queue(_n_frames);
         } else {
             for (int s = 0; s < _n_frames; s++) {
-                outputs[0][s] = 0.;
-                outputs[1][s] = 0.;
+                _output[s] = 0.;
             }
         }
     }
diff --git a/synth/tx_envelope.h b/synth/tx_envelope.h
index fb160aa..17a5952 100644
--- a/synth/tx_envelope.h
+++ b/synth/tx_envelope.h
@@ -17,6 +17,7 @@ enum env_state {
 
 class tx_envelope {
 public:
+    env_state state;
     float attack1_rate;
     float attack1_level;
     float attack2_rate;
@@ -259,7 +260,6 @@ private:
     double samplerate;
     int phase;
     float level;
-    env_state state;
     float start_level;
     float h1;
     float h2;
diff --git a/synth/tx_voice.h b/synth/tx_voice.h
index 2f06038..198e7a6 100644
--- a/synth/tx_voice.h
+++ b/synth/tx_voice.h
@@ -2,6 +2,9 @@
 #include "tx_sineosc.h"
 #include "tx_envelope.h"
 #include "tx_operator.h"
+#include "../util/audio_math.h"
+
+using namespace trnr::lib::util;
 
 namespace trnr::lib::synth {
 
@@ -22,7 +25,7 @@ public:
 
     bool gate = false;
     bool trigger = false;
-    float frequency = 100.f;
+    int midi_note = 0;
     float velocity = 1.f;
 
     int algorithm;
@@ -35,9 +38,20 @@ public:
     tx_operator op2;
     tx_operator op3;
 
+    void note_on(int _note, float _velocity) {
+        this->gate = true;
+        this->trigger = true;
+        midi_note = _note;
+        velocity = _velocity;
+    }
+
+    void note_off() {
+        this->gate = false;
+    }
+
     float process_sample() {
         float pitch_env_signal = pitch_env.process_sample(gate, trigger) * pitch_env_amt;
-        float pitched_freq = frequency + pitch_env_signal;
+        float pitched_freq = midi_to_frequency(midi_note) + pitch_env_signal;
 
         float output = 0.f;
 
diff --git a/synth/voice_allocator.h b/synth/voice_allocator.h
index 97bc375..24203eb 100644
--- a/synth/voice_allocator.h
+++ b/synth/voice_allocator.h
@@ -36,7 +36,7 @@ public:
     void note_off(const note_event& event)
     {
         for (auto it = voices.begin(); it != voices.end(); it++) {
-            if ((*it).MidiNote == event.midi_note) {
+            if ((*it).midi_note == event.midi_note) {
                 (*it).note_off();
             }
         }
diff --git a/util/audio_math.h b/util/audio_math.h
index 13efef5..f7ddee2 100644
--- a/util/audio_math.h
+++ b/util/audio_math.h
@@ -8,4 +8,8 @@ namespace trnr::lib::util {
 	static inline double db_2_lin(double db) {
 		return pow(10, db/20);
 	}
+
+	static inline float midi_to_frequency(int midi_note) {
+			return 440.0 * powf(2.0, ((float)midi_note - 69.0) / 12.0);
+	}
 }
\ No newline at end of file