diff --git a/sdrbase/sdrbase.pro b/sdrbase/sdrbase.pro
index 54436d149..fa6d0d6ed 100644
--- a/sdrbase/sdrbase.pro
+++ b/sdrbase/sdrbase.pro
@@ -76,7 +76,7 @@ SOURCES += audio/audiodevicemanager.cpp\
         dsp/fftengine.cpp\
         dsp/kissengine.cpp\
         dsp/fftcorr.cpp\
-        dsp/fftfilt.cxx\
+        dsp/fftfilt.cpp\
         dsp/fftwindow.cpp\
         dsp/filterrc.cpp\
         dsp/filtermbe.cpp\