diff --git a/sdrbase/dsp/spectrumvis.h b/sdrbase/dsp/spectrumvis.h
index 1159b185f..8deffaf5f 100644
--- a/sdrbase/dsp/spectrumvis.h
+++ b/sdrbase/dsp/spectrumvis.h
@@ -142,6 +142,7 @@ public:
     void setScalef(Real scalef);
 
 	virtual void feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool positiveOnly);
+    virtual void feed(const Complex *begin, unsigned int length); //!< direct FFT feed
 	void feedTriggered(const SampleVector::const_iterator& triggerPoint, const SampleVector::const_iterator& end, bool positiveOnly);
 	virtual void start();
 	virtual void stop();