diff --git a/fft.cpp b/fft.cpp
new file mode 100644
index 0000000..12c9958
--- /dev/null
+++ b/fft.cpp
@@ -0,0 +1,25 @@
+#include "fft.h"
+#include "string.h"
+
+FFT::FFT(int size)
+{
+    fftSize = size;
+
+    fftwIn = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fftSize);
+    fftwOut = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fftSize);
+    fftwPlan = fftwf_plan_dft_1d(fftSize, fftwIn, fftwOut, FFTW_FORWARD, FFTW_MEASURE);
+}
+
+FFT::~FFT()
+{
+    if (fftwPlan) fftwf_destroy_plan(fftwPlan);
+    if (fftwIn) fftwf_free(fftwIn);
+    if (fftwOut) fftwf_free(fftwOut);
+}
+
+void FFT::process(void *dest, void *source)
+{
+    memcpy(fftwIn, source, fftSize * sizeof(fftwf_complex));
+    fftwf_execute(fftwPlan);
+    memcpy(dest, fftwOut, fftSize * sizeof(fftwf_complex));
+}
diff --git a/fft.h b/fft.h
new file mode 100644
index 0000000..97f1907
--- /dev/null
+++ b/fft.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include <fftw3.h>
+
+class FFT {
+public:
+    FFT(int size);
+    ~FFT();
+    void process(void *dest, void *source);
+    int getSize() { return fftSize; }
+
+private:
+    int fftSize;
+    fftwf_complex *fftwIn = nullptr;
+    fftwf_complex *fftwOut = nullptr;
+    fftwf_plan fftwPlan = nullptr;
+};
diff --git a/inputsource.cpp b/inputsource.cpp
index 899a474..ff497c1 100644
--- a/inputsource.cpp
+++ b/inputsource.cpp
@@ -27,17 +27,11 @@ InputSource::InputSource(const char *filename, int fft_size) {
 }
 
 InputSource::~InputSource() {
-    cleanupFFTW();
+    delete fft;
     munmap(m_data, m_file_size);
     fclose(m_file);
 }
 
-void InputSource::cleanupFFTW() {
-    if (m_fftw_plan != nullptr) fftwf_destroy_plan(m_fftw_plan);
-    if (m_fftw_in != nullptr) fftwf_free(m_fftw_in);
-    if (m_fftw_out != nullptr) fftwf_free(m_fftw_out);
-}
-
 bool InputSource::getSamples(fftwf_complex *dest, int start, int length)
 {
     if (start + length >= sampleCount)
@@ -48,7 +42,7 @@ bool InputSource::getSamples(fftwf_complex *dest, int start, int length)
 }
 
 void InputSource::getViewport(float *dest, int x, int y, int width, int height, int zoom) {
-
+    fftwf_complex buffer[m_fft_size];
     fftwf_complex *sample_ptr = &m_data[y * getFFTStride()];
 
     for (int i = 0; i < height; i++) {
@@ -56,20 +50,20 @@ void InputSource::getViewport(float *dest, int x, int y, int width, int height,
         if (sample_ptr > m_data + (m_file_size/sizeof(fftwf_complex)))
             break;
 
-        memcpy(m_fftw_in, sample_ptr, m_fft_size * sizeof(fftwf_complex));
+        memcpy(buffer, sample_ptr, m_fft_size * sizeof(fftwf_complex));
 
         // Apply window
         for (int j = 0; j < m_fft_size; j++) {
-            m_fftw_in[j][0] *= m_window[j];
-            m_fftw_in[j][1] *= m_window[j];
+            buffer[j][0] *= m_window[j];
+            buffer[j][1] *= m_window[j];
         }
 
-        fftwf_execute(m_fftw_plan);
+        fft->process(buffer, buffer);
 
         for (int j = x; j < width; j++) {
             int k = (j + m_fft_size / 2) % m_fft_size;
-            float re = m_fftw_out[k][0];
-            float im = m_fftw_out[k][1];
+            float re = buffer[k][0];
+            float im = buffer[k][1];
             float mag = sqrt(re * re + im * im) / m_fft_size;
             float magdb = 10 * log2(mag) / log2(10);
             *dest = magdb;
@@ -88,13 +82,10 @@ int InputSource::getWidth() {
 }
 
 void InputSource::setFFTSize(int size) {
-    cleanupFFTW();
+    delete fft;
+    fft = new FFT(size);
     m_fft_size = size;
 
-    m_fftw_in = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * m_fft_size);
-    m_fftw_out = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * m_fft_size);
-    m_fftw_plan = fftwf_plan_dft_1d(m_fft_size, m_fftw_in, m_fftw_out, FFTW_FORWARD, FFTW_MEASURE);
-
     m_window.reset(new float[m_fft_size]);
     for (int i = 0; i < m_fft_size; i++) {
         m_window[i] = 0.5f * (1.0f - cos(Tau * i / (m_fft_size - 1)));
diff --git a/inputsource.h b/inputsource.h
index 45bd189..0d127ac 100644
--- a/inputsource.h
+++ b/inputsource.h
@@ -1,4 +1,6 @@
 #pragma once
+
+#include "fft.h"
 #include <fftw3.h>
 #include <memory>
 
@@ -11,9 +13,7 @@ private:
     fftwf_complex *m_data;
     int m_fft_size;
 
-    fftwf_complex *m_fftw_in = nullptr;
-    fftwf_complex *m_fftw_out = nullptr;
-    fftwf_plan m_fftw_plan = nullptr;
+    FFT *fft = nullptr;
 
     std::unique_ptr<float[]> m_window;
 
@@ -21,7 +21,6 @@ private:
     int m_max_zoom;
 
     int getFFTStride();
-    void cleanupFFTW();
     
 
 public:
diff --git a/inspectrum.pro b/inspectrum.pro
index 01fb30a..c67d27b 100644
--- a/inspectrum.pro
+++ b/inspectrum.pro
@@ -4,5 +4,5 @@ TARGET = inspectrum
 TEMPLATE = app
 
 LIBS += -lfftw3f
-HEADERS += mainwindow.h inputsource.h spectrogram.h spectrogramcontrols.h
-SOURCES += main.cpp mainwindow.cpp inputsource.cpp spectrogram.cpp spectrogramcontrols.cpp
+HEADERS += mainwindow.h fft.h inputsource.h spectrogram.h spectrogramcontrols.h
+SOURCES += main.cpp fft.cpp mainwindow.cpp inputsource.cpp spectrogram.cpp spectrogramcontrols.cpp