diff --git a/CMakeLists.txt b/CMakeLists.txt
index 004e535..4cb23b8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -42,9 +42,8 @@ qt_standard_project_setup()
 
 qt_add_executable(metabolus
     src/main.cpp
-    src/MainWindow.cpp
-    src/MainWindow.h
-    src/MainWindow.ui
+    src/ui/MainWindow.cpp
+    src/ui/MainWindow.h
     src/ParameterStore.h
     src/KeyboardController.cpp
     src/KeyboardController.h
@@ -57,6 +56,8 @@ qt_add_executable(metabolus
     src/synth/Synth.cpp
     src/synth/Synth.h
     resources/resources.qrc
+    src/ui/MainWindow.ui
+    src/ui/SmartSlider.ui
 )
 
 if (WIN32)
diff --git a/src/MainWindow.cpp b/src/MainWindow.cpp
deleted file mode 100644
index 21e0914..0000000
--- a/src/MainWindow.cpp
+++ /dev/null
@@ -1,118 +0,0 @@
-
-#include "MainWindow.h"
-
-#include <QTimer>
-#include "ui_MainWindow.h"
-
-#include "ParameterStore.h"
-
-MainWindow::MainWindow(QWidget *parent) :
-    QMainWindow(parent),
-    ui(new Ui::MainWindow),
-    audio_(new AudioEngine()),
-    keyboard_(audio_->noteQueue()) {
-
-    ui->setupUi(this);
-    setFocusPolicy(Qt::StrongFocus);
-
-    // Initialize UI
-    updateCounterLabel();
-
-    // Connect buttons to slots
-    connect(ui->buttonIncrement, &QPushButton::clicked, this, &MainWindow::onIncrementClicked);
-    connect(ui->buttonReset, &QPushButton::clicked, this, &MainWindow::onResetClicked);
-
-    // slider business
-    // TODO: smart slider widget
-    connect(ui->slider,     &QSlider::valueChanged,      this, &MainWindow::onSliderValueChanged);
-    connect(ui->inputMin,   &QLineEdit::editingFinished, this, &MainWindow::onMinChanged);
-    connect(ui->inputMax,   &QLineEdit::editingFinished, this, &MainWindow::onMaxChanged);
-    connect(ui->inputStep,  &QLineEdit::editingFinished, this, &MainWindow::onStepChanged);
-    connect(ui->inputValue, &QLineEdit::editingFinished, this, &MainWindow::onValueChanged);
-
-    // synth business
-    audio_->start();
-
-    // init defaults
-    // TODO:: there's gotta be a better way
-    ui->slider->setValue(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].def);
-    ui->slider->setMinimum(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].min);
-    ui->slider->setMaximum(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].max);
-    ui->inputValue->setText(QString::number(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].def));
-    ui->inputMin->setText(QString::number(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].min));
-    ui->inputMax->setText(QString::number(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].max));
-}
-
-MainWindow::~MainWindow() {
-    delete ui;
-}
-
-void MainWindow::keyPressEvent(QKeyEvent* event) {
-    keyboard_.handleKeyPress(event);
-}
-
-void MainWindow::keyReleaseEvent(QKeyEvent* event) {
-    keyboard_.handleKeyRelease(event);
-}
-
-void MainWindow::onIncrementClicked() {
-    counter_++;
-    updateCounterLabel();
-}
-
-void MainWindow::onResetClicked() {
-    counter_ = 0;
-    updateCounterLabel();
-}
-
-void MainWindow::updateCounterLabel() {
-    ui->labelCounter->setText(QString::number(counter_));
-}
-
-// allows only numbers to be set
-void MainWindow::onSliderValueChanged(int value) { 
-    QSignalBlocker blocker(ui->inputValue);
-    ui->inputValue->setText(QString::number(value));
-
-    // forward value so synthesizer can read
-    audio_->parameters()->set(ParamId::Osc1Frequency, static_cast<float>(value));
-}
-
-// allows only values within the min, max to be set by the text field
-void MainWindow::onValueChanged() {
-    bool ok = false;
-    int value = ui->inputValue->text().toInt(&ok);
-    if(!ok) return;
-
-    value = qBound(ui->slider->minimum(), value, ui->slider->maximum());
-    ui->slider->setValue(value);
-}
-
-void MainWindow::applySliderRange() {
-    bool minOk, maxOk;
-    int min = ui->inputMin->text().toInt(&minOk);
-    int max = ui->inputMax->text().toInt(&maxOk);
-    if(!minOk || !maxOk || min > max) return;
-    
-    ui->slider->setRange(min, max);
-
-    syncValueToUi(ui->slider->value());
-}
-
-void MainWindow::applySliderStep() {
-    bool ok;
-    int step = ui->inputStep->text().toInt(&ok);
-    if(!ok || step <= 0) return;
-    
-    ui->slider->setSingleStep(step);
-    ui->slider->setPageStep(step);
-}
-
-void MainWindow::syncValueToUi(int value) {
-    QSignalBlocker block1(ui->slider);
-    QSignalBlocker block2(ui->inputValue);
-
-    value = qBound(ui->slider->minimum(), value, ui->slider->maximum());
-    ui->slider->setValue(value);
-    ui->inputValue->setText(QString::number(value));
-}
diff --git a/src/main.cpp b/src/main.cpp
index a93a0a3..dea8c3a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,7 +1,7 @@
 
 #include <QApplication>
 
-#include "MainWindow.h"
+#include "ui/MainWindow.h"
 
 #include <iostream>
 
diff --git a/src/synth/Synth.cpp b/src/synth/Synth.cpp
index 105ca5c..347e626 100644
--- a/src/synth/Synth.cpp
+++ b/src/synth/Synth.cpp
@@ -88,7 +88,7 @@ void Synth::process(float* out, uint32_t nFrames, uint32_t sampleRate) {
         float sineSample = std::sin(phase_);
         float squareSample = -0.707f;
         if(phase_ >= M_PI) squareSample = 0.707f;
-        sampleOut = sineSample * gain;
+        sampleOut = squareSample * gain;
 
         // write to buffer
         out[2*i] = sampleOut; // left
diff --git a/src/ui/MainWindow.cpp b/src/ui/MainWindow.cpp
new file mode 100644
index 0000000..b5afbc9
--- /dev/null
+++ b/src/ui/MainWindow.cpp
@@ -0,0 +1,118 @@
+
+#include "MainWindow.h"
+
+#include <QTimer>
+#include "ui_MainWindow.h"
+
+#include "../ParameterStore.h"
+
+MainWindow::MainWindow(QWidget *parent) :
+    QMainWindow(parent),
+    ui_(new Ui::MainWindow),
+    audio_(new AudioEngine()),
+    keyboard_(audio_->noteQueue()) {
+
+    ui_->setupUi(this);
+    setFocusPolicy(Qt::StrongFocus);
+
+    // Initialize UI
+    updateCounterLabel();
+
+    // Connect buttons to slots
+    connect(ui_->buttonIncrement, &QPushButton::clicked, this, &MainWindow::onIncrementClicked);
+    connect(ui_->buttonReset, &QPushButton::clicked, this, &MainWindow::onResetClicked);
+
+    // slider business
+    // TODO: smart slider widget
+    connect(ui_->slider,     &QSlider::valueChanged,      this, &MainWindow::onSliderValueChanged);
+    connect(ui_->inputMin,   &QLineEdit::editingFinished, this, &MainWindow::onMinChanged);
+    connect(ui_->inputMax,   &QLineEdit::editingFinished, this, &MainWindow::onMaxChanged);
+    connect(ui_->inputStep,  &QLineEdit::editingFinished, this, &MainWindow::onStepChanged);
+    connect(ui_->inputValue, &QLineEdit::editingFinished, this, &MainWindow::onValueChanged);
+
+    // synth business
+    audio_->start();
+
+    // init defaults
+    // TODO:: there's gotta be a better way
+    ui_->slider->setValue(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].def);
+    ui_->slider->setMinimum(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].min);
+    ui_->slider->setMaximum(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].max);
+    ui_->inputValue->setText(QString::number(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].def));
+    ui_->inputMin->setText(QString::number(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].min));
+    ui_->inputMax->setText(QString::number(PARAM_DEFS[static_cast<size_t>(ParamId::Osc1Frequency)].max));
+}
+
+MainWindow::~MainWindow() {
+    delete ui_;
+}
+
+void MainWindow::keyPressEvent(QKeyEvent* event) {
+    keyboard_.handleKeyPress(event);
+}
+
+void MainWindow::keyReleaseEvent(QKeyEvent* event) {
+    keyboard_.handleKeyRelease(event);
+}
+
+void MainWindow::onIncrementClicked() {
+    counter_++;
+    updateCounterLabel();
+}
+
+void MainWindow::onResetClicked() {
+    counter_ = 0;
+    updateCounterLabel();
+}
+
+void MainWindow::updateCounterLabel() {
+    ui_->labelCounter->setText(QString::number(counter_));
+}
+
+// allows only numbers to be set
+void MainWindow::onSliderValueChanged(int value) { 
+    QSignalBlocker blocker(ui_->inputValue);
+    ui_->inputValue->setText(QString::number(value));
+
+    // forward value so synthesizer can read
+    audio_->parameters()->set(ParamId::Osc1Frequency, static_cast<float>(value));
+}
+
+// allows only values within the min, max to be set by the text field
+void MainWindow::onValueChanged() {
+    bool ok = false;
+    int value = ui_->inputValue->text().toInt(&ok);
+    if(!ok) return;
+
+    value = qBound(ui_->slider->minimum(), value, ui_->slider->maximum());
+    ui_->slider->setValue(value);
+}
+
+void MainWindow::applySliderRange() {
+    bool minOk, maxOk;
+    int min = ui_->inputMin->text().toInt(&minOk);
+    int max = ui_->inputMax->text().toInt(&maxOk);
+    if(!minOk || !maxOk || min > max) return;
+    
+    ui_->slider->setRange(min, max);
+
+    syncValueToUi(ui_->slider->value());
+}
+
+void MainWindow::applySliderStep() {
+    bool ok;
+    int step = ui_->inputStep->text().toInt(&ok);
+    if(!ok || step <= 0) return;
+    
+    ui_->slider->setSingleStep(step);
+    ui_->slider->setPageStep(step);
+}
+
+void MainWindow::syncValueToUi(int value) {
+    QSignalBlocker block1(ui_->slider);
+    QSignalBlocker block2(ui_->inputValue);
+
+    value = qBound(ui_->slider->minimum(), value, ui_->slider->maximum());
+    ui_->slider->setValue(value);
+    ui_->inputValue->setText(QString::number(value));
+}
diff --git a/src/MainWindow.h b/src/ui/MainWindow.h
similarity index 93%
rename from src/MainWindow.h
rename to src/ui/MainWindow.h
index e1450b3..78ee455 100644
--- a/src/MainWindow.h
+++ b/src/ui/MainWindow.h
@@ -4,7 +4,7 @@
 #include <QMainWindow>
 #include <QKeyEvent>
 
-#include "synth/AudioEngine.h"
+#include "../synth/AudioEngine.h"
 
 QT_BEGIN_NAMESPACE
 namespace Ui {
@@ -35,7 +35,7 @@ private slots:
     void onValueChanged();
 
 private:
-    Ui::MainWindow *ui;
+    Ui::MainWindow *ui_;
     int counter_ = 0;
 
     int value = 0;
diff --git a/src/MainWindow.ui b/src/ui/MainWindow.ui
similarity index 100%
rename from src/MainWindow.ui
rename to src/ui/MainWindow.ui
diff --git a/src/ui/SmartSlider.ui b/src/ui/SmartSlider.ui
new file mode 100644
index 0000000..e69de29
diff --git a/src/widgets/SmartSlider.cpp b/src/widgets/SmartSlider.cpp
new file mode 100644
index 0000000..1af64eb
--- /dev/null
+++ b/src/widgets/SmartSlider.cpp
@@ -0,0 +1,35 @@
+
+#include "SmartSlider.h"
+
+SmartSlider(QWidget* parent = nullptr) {
+
+}
+
+void SmartSlider::setRange(float min, float max) {
+
+}
+
+void SmartSlider::setStep(float step) {
+
+}
+
+void SmartSlider::setValue(float value) {
+
+}
+
+void SmartSlider::value() const;
+void SmartSlider::valueChanged(float value) {
+
+}
+
+void SmartSlider::onSliderChanged(int v) {
+
+}
+
+void SmartSlider::onSpinValueChanged(float v) {
+
+}
+
+void SmartSlider::onRangeChanged() {
+    
+}
diff --git a/src/widgets/SmartSlider.h b/src/widgets/SmartSlider.h
new file mode 100644
index 0000000..cb025a8
--- /dev/null
+++ b/src/widgets/SmartSlider.h
@@ -0,0 +1,37 @@
+
+#pragma once
+
+#include <QWidget>
+
+QT_BEGIN_NAMESPACE
+namespace Ui { class SmartSlider; }
+QT_END_NAMESPACE
+
+class SmartSlider : public QWidget {
+    Q_OBJECT
+
+public:
+    explicit SmartSlider(QWidget* parent = nullptr);
+    ~SmartSlider() = default;
+
+    void setRange(float min, float max);
+    void setStep(float step);
+    void setValue(float value);
+
+    void value() const;
+
+signals:
+    void valueChanged(float value);
+
+private slots:
+    void onSliderChanged(int v);
+    void onSpinValueChanged(float v);
+    void onRangeChanged();
+
+private:
+
+    Ui::SmartSlider* ui_;
+
+    int sliderResolution_ = 10000;
+
+};
\ No newline at end of file