diff --git a/dlls/dmusic/dmusic_private.h b/dlls/dmusic/dmusic_private.h
index 44d5d57910f..07f5f1d8d8d 100644
--- a/dlls/dmusic/dmusic_private.h
+++ b/dlls/dmusic/dmusic_private.h
@@ -53,8 +53,6 @@ typedef struct IReferenceClockImpl IReferenceClockImpl;
 
 typedef struct IDirectMusicInstrumentImpl IDirectMusicInstrumentImpl;
 
-typedef struct SynthPortImpl SynthPortImpl;
-
 /*****************************************************************************
  * Some stuff to make my life easier :=)
  */
@@ -159,28 +157,6 @@ struct IDirectMusicDownloadImpl {
     /* IDirectMusicDownloadImpl fields */
 };
 
-/*****************************************************************************
- * SynthPortImpl implementation structure
- */
-struct SynthPortImpl {
-    /* IUnknown fields */
-    IDirectMusicPort IDirectMusicPort_iface;
-    IDirectMusicPortDownload IDirectMusicPortDownload_iface;
-    IDirectMusicThru IDirectMusicThru_iface;
-    LONG ref;
-
-    /* IDirectMusicPort fields */
-    IDirectSound* pDirectSound;
-    IReferenceClock* pLatencyClock;
-    IDirectMusicSynth* synth;
-    IDirectMusicSynthSink* synth_sink;
-    BOOL fActive;
-    DMUS_PORTCAPS caps;
-    DMUS_PORTPARAMS params;
-    int nrofgroups;
-    DMUSIC_PRIVATE_CHANNEL_GROUP group[1];
-};
-
 /** Internal factory */
 extern HRESULT DMUSIC_CreateSynthPortImpl(LPCGUID guid, LPVOID *object, LPUNKNOWN unkouter, LPDMUS_PORTPARAMS port_params, LPDMUS_PORTCAPS port_caps, DWORD device) DECLSPEC_HIDDEN;
 extern HRESULT DMUSIC_CreateMidiOutPortImpl(LPCGUID guid, LPVOID *object, LPUNKNOWN unkouter, LPDMUS_PORTPARAMS port_params, LPDMUS_PORTCAPS port_caps, DWORD device) DECLSPEC_HIDDEN;
diff --git a/dlls/dmusic/port.c b/dlls/dmusic/port.c
index 95db9e0f4a3..b694ef78c00 100644
--- a/dlls/dmusic/port.c
+++ b/dlls/dmusic/port.c
@@ -24,6 +24,22 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(dmusic);
 
+typedef struct SynthPortImpl {
+    IDirectMusicPort IDirectMusicPort_iface;
+    IDirectMusicPortDownload IDirectMusicPortDownload_iface;
+    IDirectMusicThru IDirectMusicThru_iface;
+    LONG ref;
+    IDirectSound *pDirectSound;
+    IReferenceClock *pLatencyClock;
+    IDirectMusicSynth *synth;
+    IDirectMusicSynthSink *synth_sink;
+    BOOL fActive;
+    DMUS_PORTCAPS caps;
+    DMUS_PORTPARAMS params;
+    int nrofgroups;
+    DMUSIC_PRIVATE_CHANNEL_GROUP group[1];
+} SynthPortImpl;
+
 static inline IDirectMusicDownloadedInstrumentImpl* impl_from_IDirectMusicDownloadedInstrument(IDirectMusicDownloadedInstrument *iface)
 {
     return CONTAINING_RECORD(iface, IDirectMusicDownloadedInstrumentImpl, IDirectMusicDownloadedInstrument_iface);