diff --git a/dlls/dsound/dsound_private.h b/dlls/dsound/dsound_private.h
index e0283589b86..e1567e54e8d 100644
--- a/dlls/dsound/dsound_private.h
+++ b/dlls/dsound/dsound_private.h
@@ -52,11 +52,6 @@ typedef struct IDirectSound8_IDirectSound8   IDirectSound8_IDirectSound8;
 typedef struct IDirectSoundBufferImpl        IDirectSoundBufferImpl;
 typedef struct IDirectSoundCaptureImpl       IDirectSoundCaptureImpl;
 typedef struct IDirectSoundCaptureBufferImpl IDirectSoundCaptureBufferImpl;
-typedef struct IDirectSoundFullDuplexImpl    IDirectSoundFullDuplexImpl;
-typedef struct IDirectSoundFullDuplex_IUnknown IDirectSoundFullDuplex_IUnknown;
-typedef struct IDirectSoundFullDuplex_IDirectSound IDirectSoundFullDuplex_IDirectSound;
-typedef struct IDirectSoundFullDuplex_IDirectSound8 IDirectSoundFullDuplex_IDirectSound8;
-typedef struct IDirectSoundFullDuplex_IDirectSoundCapture IDirectSoundFullDuplex_IDirectSoundCapture;
 typedef struct IDirectSoundNotifyImpl        IDirectSoundNotifyImpl;
 typedef struct IDirectSoundCaptureNotifyImpl IDirectSoundCaptureNotifyImpl;
 typedef struct IDirectSound3DListenerImpl    IDirectSound3DListenerImpl;
@@ -309,52 +304,6 @@ HRESULT IDirectSoundCaptureBufferImpl_Create(
     IDirectSoundCaptureBufferImpl ** ppobj,
     LPCDSCBUFFERDESC lpcDSCBufferDesc);
 
-/*****************************************************************************
- * IDirectSoundFullDuplex implementation structure
- */
-struct IDirectSoundFullDuplexImpl
-{
-    /* IUnknown fields */
-    const IDirectSoundFullDuplexVtbl *lpVtbl;
-    LONG                              ref;
-
-    /* IDirectSoundFullDuplexImpl fields */
-    DirectSoundDevice                *renderer_device;
-    DirectSoundCaptureDevice         *capture_device;
-
-    LPUNKNOWN                         pUnknown;
-    LPDIRECTSOUND                     pDS;
-    LPDIRECTSOUND8                    pDS8;
-    LPDIRECTSOUNDCAPTURE              pDSC;
-};
-
-/*****************************************************************************
- * IDirectSoundFullDuplex COM components
- */
-struct IDirectSoundFullDuplex_IUnknown {
-    const IUnknownVtbl         *lpVtbl;
-    LONG                        ref;
-    IDirectSoundFullDuplexImpl *pdsfd;
-};
-
-struct IDirectSoundFullDuplex_IDirectSound {
-    const IDirectSoundVtbl     *lpVtbl;
-    LONG                        ref;
-    IDirectSoundFullDuplexImpl *pdsfd;
-};
-
-struct IDirectSoundFullDuplex_IDirectSound8 {
-    const IDirectSound8Vtbl    *lpVtbl;
-    LONG                        ref;
-    IDirectSoundFullDuplexImpl *pdsfd;
-};
-
-struct IDirectSoundFullDuplex_IDirectSoundCapture {
-    const IDirectSoundCaptureVtbl *lpVtbl;
-    LONG                           ref;
-    IDirectSoundFullDuplexImpl    *pdsfd;
-};
-
 /*****************************************************************************
  *  IDirectSound3DListener implementation structure
  */
diff --git a/dlls/dsound/duplex.c b/dlls/dsound/duplex.c
index 1fe6bbc67da..8fbf1d622c0 100644
--- a/dlls/dsound/duplex.c
+++ b/dlls/dsound/duplex.c
@@ -37,6 +37,49 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(dsound);
 
+/*****************************************************************************
+ * IDirectSoundFullDuplex implementation structure
+ */
+typedef struct IDirectSoundFullDuplexImpl
+{
+    /* IUnknown fields */
+    const IDirectSoundFullDuplexVtbl *lpVtbl;
+    LONG                              ref;
+
+    /* IDirectSoundFullDuplexImpl fields */
+    DirectSoundDevice                *renderer_device;
+    DirectSoundCaptureDevice         *capture_device;
+
+    LPUNKNOWN                         pUnknown;
+    LPDIRECTSOUND                     pDS;
+    LPDIRECTSOUND8                    pDS8;
+    LPDIRECTSOUNDCAPTURE              pDSC;
+} IDirectSoundFullDuplexImpl;
+
+typedef struct IDirectSoundFullDuplex_IUnknown {
+    const IUnknownVtbl         *lpVtbl;
+    LONG                        ref;
+    IDirectSoundFullDuplexImpl *pdsfd;
+} IDirectSoundFullDuplex_IUnknown;
+
+typedef struct IDirectSoundFullDuplex_IDirectSound {
+    const IDirectSoundVtbl     *lpVtbl;
+    LONG                        ref;
+    IDirectSoundFullDuplexImpl *pdsfd;
+} IDirectSoundFullDuplex_IDirectSound;
+
+typedef struct IDirectSoundFullDuplex_IDirectSound8 {
+    const IDirectSound8Vtbl    *lpVtbl;
+    LONG                        ref;
+    IDirectSoundFullDuplexImpl *pdsfd;
+} IDirectSoundFullDuplex_IDirectSound8;
+
+typedef struct IDirectSoundFullDuplex_IDirectSoundCapture {
+    const IDirectSoundCaptureVtbl *lpVtbl;
+    LONG                           ref;
+    IDirectSoundFullDuplexImpl    *pdsfd;
+} IDirectSoundFullDuplex_IDirectSoundCapture;
+
 /*******************************************************************************
  * IUnknown
  */