diff --git a/include/dsp/spectrumvis.h b/include/dsp/spectrumvis.h
index 9edbbe9ef..46820dbd6 100644
--- a/include/dsp/spectrumvis.h
+++ b/include/dsp/spectrumvis.h
@@ -1,6 +1,7 @@
 #ifndef INCLUDE_SPECTRUMVIS_H
 #define INCLUDE_SPECTRUMVIS_H
 
+#include <QMutex>
 #include "dsp/samplesink.h"
 #include "dsp/fftengine.h"
 #include "fftwindow.h"
@@ -61,6 +62,8 @@ private:
 
 	GLSpectrum* m_glSpectrum;
 
+	QMutex m_mutex;
+
 	void handleConfigure(int fftSize, int overlapPercent, FFTWindow::Function window);
 };
 
diff --git a/sdrbase/dsp/spectrumvis.cpp b/sdrbase/dsp/spectrumvis.cpp
index b8b90763a..aa10c6fbe 100644
--- a/sdrbase/dsp/spectrumvis.cpp
+++ b/sdrbase/dsp/spectrumvis.cpp
@@ -21,7 +21,8 @@ SpectrumVis::SpectrumVis(GLSpectrum* glSpectrum) :
 	m_logPowerSpectrum(MAX_FFT_SIZE),
 	m_fftBufferFill(0),
 	m_needMoreSamples(false),
-	m_glSpectrum(glSpectrum)
+	m_glSpectrum(glSpectrum),
+	m_mutex(QMutex::Recursive)
 {
 	setObjectName("SpectrumVis");
 	handleConfigure(1024, 0, FFTWindow::BlackmanHarris);
@@ -77,6 +78,8 @@ void SpectrumVis::feed(const SampleVector::const_iterator& cbegin, const SampleV
 
 		if (todo >= samplesNeeded)
 		{
+			QMutexLocker mutexLocker(&m_mutex);
+
 			// fill up the buffer
 			std::vector<Complex>::iterator it = m_fftBuffer.begin() + m_fftBufferFill;
 
@@ -174,6 +177,8 @@ bool SpectrumVis::handleMessage(const Message& message)
 
 void SpectrumVis::handleConfigure(int fftSize, int overlapPercent, FFTWindow::Function window)
 {
+	QMutexLocker mutexLocker(&m_mutex);
+
 	if (fftSize > MAX_FFT_SIZE)
 	{
 		fftSize = MAX_FFT_SIZE;