diff --git a/src/sound/mididevices/music_win_mididevice.cpp b/src/sound/mididevices/music_win_mididevice.cpp
index 1bc42116e2..94c8a0b36a 100644
--- a/src/sound/mididevices/music_win_mididevice.cpp
+++ b/src/sound/mididevices/music_win_mididevice.cpp
@@ -42,6 +42,7 @@
 
 #include "i_musicinterns.h"
 #include "templates.h"
+#include "doomdef.h"
 #include "m_swap.h"
 #include "doomerrors.h"
 
diff --git a/src/sound/music/i_music.h b/src/sound/music/i_music.h
index 714cbd95fd..421bf1355a 100644
--- a/src/sound/music/i_music.h
+++ b/src/sound/music/i_music.h
@@ -34,6 +34,7 @@
 #ifndef __I_MUSIC_H__
 #define __I_MUSIC_H__
 
+#include "doomdef.h"
 #include "i_soundinternal.h"
 
 class FileReader;
diff --git a/src/sound/music/i_musicinterns.h b/src/sound/music/i_musicinterns.h
index 53d2b81a73..09bba62dca 100644
--- a/src/sound/music/i_musicinterns.h
+++ b/src/sound/music/i_musicinterns.h
@@ -5,6 +5,7 @@
 #include "mus2midi.h"
 #include "i_sound.h"
 #include "i_music.h"
+#include "s_sound.h"
 #include "files.h"
 #include "wildmidi/wildmidi_lib.h"
 #include "midisources/midisource.h"
diff --git a/src/sound/timidity/instrum_dls.cpp b/src/sound/timidity/instrum_dls.cpp
index 1ddf666074..bc6b5b5d27 100644
--- a/src/sound/timidity/instrum_dls.cpp
+++ b/src/sound/timidity/instrum_dls.cpp
@@ -26,6 +26,7 @@
 #include <math.h>
 
 #include "timidity.h"
+#include "doomdef.h"
 
 #define __Sound_SetError(x)
 
diff --git a/src/sound/timidity/instrum_sf2.cpp b/src/sound/timidity/instrum_sf2.cpp
index 87b5ee4bea..3f50f15750 100644
--- a/src/sound/timidity/instrum_sf2.cpp
+++ b/src/sound/timidity/instrum_sf2.cpp
@@ -4,6 +4,7 @@
 #include <math.h>
 #include <memory>
 
+#include "doomdef.h"
 #include "m_swap.h"
 #include "templates.h"
 #include "timidity.h"