diff --git a/src/Sound/beacon.cxx b/src/Sound/beacon.cxx
index ad938c0c6..0ce8fb90c 100644
--- a/src/Sound/beacon.cxx
+++ b/src/Sound/beacon.cxx
@@ -24,6 +24,7 @@
 #include "beacon.hxx"
 
 #include <simgear/structure/exception.hxx>
+#include <Main/globals.hxx>
 
 // constructor
 FGBeacon::FGBeacon()
diff --git a/src/Sound/morse.cxx b/src/Sound/morse.cxx
index 92b671bca..2d21be642 100644
--- a/src/Sound/morse.cxx
+++ b/src/Sound/morse.cxx
@@ -23,6 +23,8 @@
 
 #include <simgear/constants.h>
 
+#include <Main/globals.hxx>
+
 #include "morse.hxx"