diff --git a/src/AppFrame.cpp b/src/AppFrame.cpp
index abc07dc..03f02a5 100644
--- a/src/AppFrame.cpp
+++ b/src/AppFrame.cpp
@@ -719,7 +719,7 @@ void AppFrame::OnTimer(wxTimerEvent& event) {
     } else {
         fftDistrib.setFFTSize(DEFAULT_FFT_SIZE);
     }
-    fftDistrib.setLinesPerSecond(15);
+    fftDistrib.setLinesPerSecond(60);
     fftDistrib.run();
 
     wproc->setView(waterfallCanvas->getViewState());
diff --git a/src/CubicSDR.cpp b/src/CubicSDR.cpp
index 8619b71..51deb24 100644
--- a/src/CubicSDR.cpp
+++ b/src/CubicSDR.cpp
@@ -64,6 +64,7 @@ bool CubicSDR::OnInit() {
     pipeIQVisualData->set_max_num_items(1);
     
     pipeWaterfallIQVisualData = new DemodulatorThreadInputQueue();
+    pipeWaterfallIQVisualData->set_max_num_items(512);
     
     spectrumDistributor.attachOutput(pipeDemodIQVisualData);
     spectrumDistributor.attachOutput(pipeSpectrumIQVisualData);
@@ -85,7 +86,7 @@ bool CubicSDR::OnInit() {
     sdrThread->setOutputQueue("IQDataOutput",pipeSDRIQData);
 
     sdrPostThread = new SDRPostThread();
-    sdrPostThread->setNumVisSamples(16384 * 2);
+    sdrPostThread->setNumVisSamples(BUF_SIZE);
     sdrPostThread->setInputQueue("IQDataInput", pipeSDRIQData);
     sdrPostThread->setOutputQueue("IQVisualDataOutput", pipeIQVisualData);
     sdrPostThread->setOutputQueue("IQDataOutput", pipeWaterfallIQVisualData);
diff --git a/src/process/SpectrumVisualProcessor.h b/src/process/SpectrumVisualProcessor.h
index a757a88..bcbca01 100644
--- a/src/process/SpectrumVisualProcessor.h
+++ b/src/process/SpectrumVisualProcessor.h
@@ -68,7 +68,7 @@ private:
 
 class FFTDataDistributor : public VisualProcessor<DemodulatorThreadIQData, DemodulatorThreadIQData> {
 public:
-    FFTDataDistributor() : linesPerSecond(30) {
+    FFTDataDistributor() : linesPerSecond(30), lineRateAccum(0.0) {
     }
     
     void setFFTSize(int fftSize) {
@@ -87,7 +87,13 @@ protected:
             }
             DemodulatorThreadIQData *inp;
             input->pop(inp);
+
+            int fftSize = this->fftSize;
             
+            if (fftSize > inp->data.size()) {
+                fftSize = inp->data.size();
+            }
+
             // number of milliseconds contained in input
             double inputTime = (double)inp->data.size() / (double)inp->sampleRate;
             // number of lines in input
@@ -98,7 +104,7 @@ protected:
             
             if (inp) {
                 if (inp->data.size() >= fftSize) {
-                    for (int i = 0, iMax = inp->data.size()-fftSize; i < iMax; i += fftSize) {
+                    for (int i = 0, iMax = inp->data.size()-fftSize; i <= iMax; i += fftSize) {
                         lineRateAccum += lineRateStep;
                         
                         if (lineRateAccum >= 1.0) {
@@ -108,7 +114,7 @@ protected:
                             outp->data.assign(inp->data.begin()+i,inp->data.begin()+i+fftSize);
                             distribute(outp);
                             
-                            while (lineRateAccum > 1.0) {
+                            while (lineRateAccum >= 1.0) {
                                 lineRateAccum -= 1.0;
                             }
                         }
diff --git a/src/visual/SpectrumCanvas.cpp b/src/visual/SpectrumCanvas.cpp
index c9df1f0..f07ae9c 100644
--- a/src/visual/SpectrumCanvas.cpp
+++ b/src/visual/SpectrumCanvas.cpp
@@ -32,7 +32,8 @@ SpectrumCanvas::SpectrumCanvas(wxWindow *parent, int *attribList) :
     glContext = new PrimaryGLContext(this, &wxGetApp().GetContext(this));
 
     mouseTracker.setVertDragLock(true);
-
+    visualDataQueue.set_max_num_items(1);
+            
     SetCursor(wxCURSOR_SIZEWE);
 }
 
diff --git a/src/visual/WaterfallCanvas.cpp b/src/visual/WaterfallCanvas.cpp
index af56d8f..51d1723 100644
--- a/src/visual/WaterfallCanvas.cpp
+++ b/src/visual/WaterfallCanvas.cpp
@@ -90,8 +90,8 @@ void WaterfallCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
             centerFreq = getCenterFrequency();
             bw = getBandwidth();
             bw = (long long) ceil((long double) bw * currentZoom);
-            if (bw < 100000) {
-                bw = 100000;
+            if (bw < 30000) {
+                bw = 30000;
             }
             if (mouseTracker.mouseInView()) {
                 long long mfreqA = getFrequencyAt(mouseTracker.getMouseX());