diff --git a/interface/src/Audio.cpp b/interface/src/Audio.cpp
index 80500d392d..71b64d7c6e 100644
--- a/interface/src/Audio.cpp
+++ b/interface/src/Audio.cpp
@@ -506,30 +506,34 @@ void Audio::handleAudioInput() {
 
     QByteArray inputByteArray = _inputDevice->readAll();
 
-    int16_t* inputFrameData = (int16_t*)inputByteArray.data();
-    const int inputFrameCount = inputByteArray.size() / sizeof(int16_t);
+    if (!_muted && (_audioSourceInjectEnabled || _peqEnabled)) {
+        
+        int16_t* inputFrameData = (int16_t*)inputByteArray.data();
+        const int inputFrameCount = inputByteArray.size() / sizeof(int16_t);
 
-    _inputFrameBuffer.copyFrames(1, inputFrameCount, inputFrameData, false /*copy in*/);
+        _inputFrameBuffer.copyFrames(1, inputFrameCount, inputFrameData, false /*copy in*/);
 
- //   _inputGain.render(_inputFrameBuffer);  // input/mic gain+mute
-    
-    //  Add audio source injection if enabled
-    if (_audioSourceInjectEnabled && !_muted) {
-     
-        if (_toneSourceEnabled) {  // sine generator
-            _toneSource.render(_inputFrameBuffer);
+#if ENABLE_INPUT_GAIN
+        _inputGain.render(_inputFrameBuffer);  // input/mic gain+mute
+#endif
+        //  Add audio source injection if enabled
+        if (_audioSourceInjectEnabled) {
+         
+            if (_toneSourceEnabled) {  // sine generator
+                _toneSource.render(_inputFrameBuffer);
+            }
+            else if(_noiseSourceEnabled) { // pink noise generator
+                _noiseSource.render(_inputFrameBuffer);
+            }
+            _sourceGain.render(_inputFrameBuffer); // post gain
         }
-        else if(_noiseSourceEnabled) { // pink noise generator
-            _noiseSource.render(_inputFrameBuffer);
+        if (_peqEnabled) {
+            _peq.render(_inputFrameBuffer); // 3-band parametric eq
         }
-        _sourceGain.render(_inputFrameBuffer); // post gain
-    }
-    if (_peqEnabled && !_muted) {
-        _peq.render(_inputFrameBuffer); // 3-band parametric eq
-    }
 
-    _inputFrameBuffer.copyFrames(1, inputFrameCount, inputFrameData, true /*copy out*/);
-    
+        _inputFrameBuffer.copyFrames(1, inputFrameCount, inputFrameData, true /*copy out*/);
+    }
+        
     if (Menu::getInstance()->isOptionChecked(MenuOption::EchoLocalAudio) && !_muted && _audioOutput) {
         // if this person wants local loopback add that to the locally injected audio
 
diff --git a/libraries/audio/src/AudioSourceTone.cpp b/libraries/audio/src/AudioSourceTone.cpp
deleted file mode 100644
index 80a6aed48e..0000000000
--- a/libraries/audio/src/AudioSourceTone.cpp
+++ /dev/null
@@ -1,20 +0,0 @@
-//
-//  AudioSourceTone.cpp
-//  hifi
-//
-//  Created by Craig Hansen-Sturm on 8/10/14.
-//  Copyright 2014 High Fidelity, Inc.
-//
-//  Distributed under the Apache License, Version 2.0.
-//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
-//
-
-#include <assert.h>
-#include <math.h>
-#include <SharedUtil.h>
-#include "AudioRingBuffer.h"
-#include "AudioFormat.h"
-#include "AudioBuffer.h"
-#include "AudioSourceTone.h"
-
-uint32_t AudioSourceTone::_frameOffset = 0;
diff --git a/libraries/audio/src/AudioSourceTone.h b/libraries/audio/src/AudioSourceTone.h
index 5ebe1ba2a9..4a9046a6b2 100644
--- a/libraries/audio/src/AudioSourceTone.h
+++ b/libraries/audio/src/AudioSourceTone.h
@@ -12,13 +12,23 @@
 #ifndef hifi_AudioSourceTone_h
 #define hifi_AudioSourceTone_h
 
+// Implements a two-pole Gordon-Smith oscillator
 class AudioSourceTone
 {
-    static uint32_t _frameOffset;
     float32_t _frequency;
     float32_t _amplitude;
     float32_t _sampleRate;
     float32_t _omega;
+    float32_t _epsilon;
+    float32_t _yq1;  
+    float32_t _y1;
+    
+    void updateCoefficients() {
+        _omega = _frequency / _sampleRate * TWO_PI;
+        _epsilon = 2.0f * sinf(_omega / 2.0f);
+        _yq1 = cosf(-1.0f * _omega);
+        _y1 = sinf(+1.0f * _omega);
+    }
     
 public:
     AudioSourceTone() {
@@ -30,22 +40,22 @@ public:
     }
     
     void initialize() {
-        _frameOffset = 0;
-        setParameters(SAMPLE_RATE, 220.0f, 0.9f);
+        const float32_t FREQUENCY_220_HZ = 220.0f;
+        const float32_t GAIN_MINUS_3DB = 0.708f;
+        setParameters(SAMPLE_RATE, FREQUENCY_220_HZ, GAIN_MINUS_3DB);
     }
     
     void finalize() {
     }
     
     void reset() {
-        _frameOffset = 0;
     }
 
     void setParameters(const float32_t sampleRate, const float32_t frequency,  const float32_t amplitude) {
         _sampleRate = std::max(sampleRate, 1.0f);
         _frequency = std::max(frequency, 1.0f);
         _amplitude = std::max(amplitude, 1.0f);
-        _omega = _frequency / _sampleRate * TWO_PI;
+        updateCoefficients();
     }
     
     void getParameters(float32_t& sampleRate, float32_t& frequency, float32_t& amplitude) {
@@ -56,15 +66,22 @@ public:
 
     void render(AudioBufferFloat32& frameBuffer) {
         
-        // note: this is a placeholder implementation. final version will not include any transcendental ops in our render loop
-        
         float32_t** samples = frameBuffer.getFrameData();
+        float32_t yq;
+        float32_t y;
         for (uint16_t i = 0; i < frameBuffer.getFrameCount(); ++i) {
+            
+            yq = _yq1 - (_epsilon * _y1);
+            y = _y1 + (_epsilon * yq);
+            
+            // update delays
+            _yq1 = yq;
+            _y1 = y;
+            
             for (uint16_t j = 0; j < frameBuffer.getChannelCount(); ++j) {
-                samples[j][i] = sinf((i + _frameOffset) * _omega);
+                samples[j][i] = _amplitude * y;
             }
         }
-        _frameOffset += frameBuffer.getFrameCount();
     }
 };