diff --git a/ttd.dsp b/ttd.dsp
index 98731eebf1..aba42ca833 100644
--- a/ttd.dsp
+++ b/ttd.dsp
@@ -260,6 +260,10 @@ SOURCE=.\minilzo.c
 SOURCE=.\misc.c
 # End Source File
 
+# Begin Source File
+SOURCE=.\mixer.c
+# End Source File
+
 # Begin Source File
 SOURCE=.\namegen.c
 # End Source File
diff --git a/ttd.vcproj b/ttd.vcproj
index 6852b1359f..f19d971ce2 100644
--- a/ttd.vcproj
+++ b/ttd.vcproj
@@ -529,6 +529,9 @@
 						BasicRuntimeChecks="3"/>
 				</FileConfiguration>
 			</File>
+			<File
+				RelativePath=".\mixer.c">
+			</File>
 			<File
 				RelativePath="namegen.c">
 				<FileConfiguration
@@ -1204,6 +1207,9 @@
 			<File
 				RelativePath="md5.h">
 			</File>
+			<File
+				RelativePath=".\mixer.h">
+			</File>
 			<File
 				RelativePath=".\network.h">
 			</File>