diff --git a/plugin/module.cpp b/plugin/module.cpp
index a570676..6e82cda 100644
--- a/plugin/module.cpp
+++ b/plugin/module.cpp
@@ -26,6 +26,11 @@ Module::Module() {
 void Module::run(Voice* voice) {
     // run updates for module board
 
+// FIXME break these out to the patch setter
+	a = attackTable[patchRam.env_a];	// attack time coeff looked up in table
+	d = decayTable[patchRam.env_d];		// decay time coeff looked up in table
+	r = decayTable[patchRam.env_r];		// release time coeff looked up in table
+	s = patchRam.env_s << 7;		// scale 0x00-0x7f to 0x0000-0x3f80
     // work out the "master" cutoff
     vcfCutoff = patchRam.vcfFreq / 127.0f;
     vcfCutoff += lfo * (patchRam.vcfLfo/127.0f);
@@ -34,18 +39,17 @@ void Module::run(Voice* voice) {
     for (uint32_t i = 0; i < NUM_VOICES; i++) {
         switch (voice[i].envPhase) {
             case 0:                                                     // release phase FIXME use an enum I guess
-                voice[i].env *= decayTable[patchRam.env_r] / 65536.0f;  // "RC" decay to zero
+                voice[i].env = (voice[i].env * d) >> 16;  // "RC" decay to zero
                 break;
             case 1:                                                      // attack phase
-                voice[i].env += attackTable[patchRam.env_a] / 65536.0f;  // linear attack to 1
+                voice[i].env += a;  // linear attack to 0x3fff
                 break;
             case 2:
-                float t = patchRam.env_s / 127.0f;
-                voice[i].env = (voice[i].env - t) * (decayTable[patchRam.env_d] / 65536.0f) + t;
+                voice[i].env = (((voice[i].env - s) * d) >>16 ) + s;
                 break;
         }
-        if (voice[i].env > 1.0f) {
-            voice[i].env = 1.0f;
+        if (voice[i].env > 0x3fff) {
+            voice[i].env = 0x3fff;
             voice[i].envPhase = 2;  // flip to decay
         }
 	// per voice we need to calculate the key follow amount and envelope amount
diff --git a/plugin/module.hpp b/plugin/module.hpp
index 22d4492..3a36908 100644
--- a/plugin/module.hpp
+++ b/plugin/module.hpp
@@ -37,6 +37,9 @@ class Module {
     // precomputed values for all voices
     float pw, saw, square, sub;
 
+    // "internal state" values for patch parameters
+    uint16_t a, d, s, r;
+
     struct {
         uint8_t lfoRate = 0x30;  // lookup value defaults to 0x0200
         uint8_t lfoDelay = 0x00;
@@ -66,7 +69,7 @@ class Voice {
     void off();
     void run(Module* m, float* buffer, uint32_t samples);
     uint8_t envPhase = 0;
-    float env = 0;  // output amplitude
+    int16_t env = 0;  // output amplitude
 
    private:
     float omega = 0, theta = 0;   // phase increment and angle
@@ -78,4 +81,4 @@ class Voice {
     float b1 = 0, b2 = 0, b3 = 0, b4 = 0;
 };
 
-#endif
\ No newline at end of file
+#endif
diff --git a/plugin/voice.cpp b/plugin/voice.cpp
index abf1d62..025707c 100644
--- a/plugin/voice.cpp
+++ b/plugin/voice.cpp
@@ -51,13 +51,15 @@ void Voice::run(Module* m, float* buffer, uint32_t samples) {
     // carry out per-voice calculations for each block of samples
     float out, t, fb, res;
 
-    float cut = 0.00513 + 0.075*env;
+    float cut = 0.00513 + 0.0000075*env;
     // printf("%f ", delay);
     m->saw = 1;
     m->square = 1;
     m->sub = .5;
     m->pw = 0.5;
 
+    float amp = env / 4096.0f;
+
     for (uint32_t i = 0; i < samples; i++) {
         out = delay;
         delay = 0;
@@ -106,7 +108,7 @@ void Voice::run(Module* m, float* buffer, uint32_t samples) {
             b4 = ((b3 - b4) * cut) + b4;
         }
 
-        buffer[i] += 0.125 * env * b4;
+        buffer[i] += 0.125 * amp * b4;
         lastpw = m->pw;
     }
     // buffer[0] += 1;