diff --git a/dlls/dmusic/collection.c b/dlls/dmusic/collection.c
index 5002c9e5f49..e30f89d1219 100644
--- a/dlls/dmusic/collection.c
+++ b/dlls/dmusic/collection.c
@@ -662,7 +662,7 @@ static HRESULT WINAPI IDirectMusicCollectionImpl_IPersistStream_Load(LPPERSISTST
                                             LPDMUS_PRIVATE_INSTRUMENTENTRY new_instrument = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(DMUS_PRIVATE_INSTRUMENTENTRY));
                                             TRACE_(dmfile)(": instrument list\n");
                                             /* Only way to create this one... even M$ does it discretely */
-                                            DMUSIC_CreateDirectMusicInstrumentImpl(&IID_IDirectMusicInstrument, (LPVOID*)&new_instrument->pInstrument, NULL);
+                                            DMUSIC_CreateDirectMusicInstrumentImpl(&IID_IDirectMusicInstrument, (void**)&new_instrument->pInstrument, NULL);
                                             {
                                                 IDirectMusicInstrumentImpl *instrument = impl_from_IDirectMusicInstrument(new_instrument->pInstrument);
                                                 /* Store offset and length, they will be needed when loading the instrument */
@@ -677,14 +677,12 @@ static HRESULT WINAPI IDirectMusicCollectionImpl_IPersistStream_Load(LPPERSISTST
                                                     switch (chunk.fccID) {
                                                         case FOURCC_INSH: {
                                                             TRACE_(dmfile)(": instrument header chunk\n");
-                                                            instrument->pHeader = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, chunk.dwSize);
-                                                            IStream_Read(stream, instrument->pHeader, chunk.dwSize, NULL);
+                                                            IStream_Read(stream, &instrument->header, chunk.dwSize, NULL);
                                                             break;
                                                         }
                                                         case FOURCC_DLID: {
                                                             TRACE_(dmfile)(": DLID (GUID) chunk\n");
-                                                            instrument->pInstrumentID = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, chunk.dwSize);
-                                                            IStream_Read(stream, instrument->pInstrumentID, chunk.dwSize, NULL);
+                                                            IStream_Read(stream, &instrument->id, chunk.dwSize, NULL);
                                                             break;
                                                         }
                                                         case FOURCC_LIST: {
@@ -712,14 +710,14 @@ static HRESULT WINAPI IDirectMusicCollectionImpl_IPersistStream_Load(LPPERSISTST
                                                 /* DEBUG: dumps whole instrument object tree: */
                                                 if (TRACE_ON(dmusic)) {
                                                     TRACE("*** IDirectMusicInstrument (%p) ***\n", instrument);
-                                                    if (instrument->pInstrumentID)
-                                                        TRACE(" - GUID = %s\n", debugstr_dmguid(instrument->pInstrumentID));
+                                                    if (!IsEqualGUID(&instrument->id, &GUID_NULL))
+                                                        TRACE(" - GUID = %s\n", debugstr_dmguid(&instrument->id));
                                                     TRACE(" - Instrument header:\n");
-                                                    TRACE("    - cRegions: %d\n", instrument->pHeader->cRegions);
+                                                    TRACE("    - cRegions: %d\n", instrument->header.cRegions);
                                                     TRACE("    - Locale:\n");
-                                                    TRACE("       - ulBank: %d\n", instrument->pHeader->Locale.ulBank);
-                                                    TRACE("       - ulInstrument: %d\n", instrument->pHeader->Locale.ulInstrument);
-                                                    TRACE("       => dwPatch: %d\n", MIDILOCALE2Patch(&instrument->pHeader->Locale));
+                                                    TRACE("       - ulBank: %d\n", instrument->header.Locale.ulBank);
+                                                    TRACE("       - ulInstrument: %d\n", instrument->header.Locale.ulInstrument);
+                                                    TRACE("       => dwPatch: %d\n", MIDILOCALE2Patch(&instrument->header.Locale));
                                                 }
                                                 list_add_tail(&This->Instruments, &new_instrument->entry);
                                             }
diff --git a/dlls/dmusic/dmusic_private.h b/dlls/dmusic/dmusic_private.h
index a37a1c3c663..3e5c6c25051 100644
--- a/dlls/dmusic/dmusic_private.h
+++ b/dlls/dmusic/dmusic_private.h
@@ -238,8 +238,8 @@ struct IDirectMusicInstrumentImpl {
     /* IDirectMusicInstrumentImpl fields */
     LARGE_INTEGER liInstrumentPosition; /* offset in a stream where instrument chunk can be found */
     ULONG length; /* Length of the instrument in the stream */
-    LPGUID pInstrumentID;
-    LPINSTHEADER pHeader;
+    GUID id;
+    INSTHEADER header;
     WCHAR wszName[DMUS_MAX_NAME];
     /* instrument data */
     BOOL loaded;
diff --git a/dlls/dmusic/instrument.c b/dlls/dmusic/instrument.c
index 13d0c2fda03..d6de0db9f48 100644
--- a/dlls/dmusic/instrument.c
+++ b/dlls/dmusic/instrument.c
@@ -92,7 +92,7 @@ static HRESULT WINAPI IDirectMusicInstrumentImpl_GetPatch(LPDIRECTMUSICINSTRUMEN
 
     TRACE("(%p)->(%p)\n", This, pdwPatch);
 
-    *pdwPatch = MIDILOCALE2Patch(&This->pHeader->Locale);
+    *pdwPatch = MIDILOCALE2Patch(&This->header.Locale);
 
     return S_OK;
 }
@@ -103,7 +103,7 @@ static HRESULT WINAPI IDirectMusicInstrumentImpl_SetPatch(LPDIRECTMUSICINSTRUMEN
 
     TRACE("(%p)->(%d): stub\n", This, dwPatch);
 
-    Patch2MIDILOCALE(dwPatch, &This->pHeader->Locale);
+    Patch2MIDILOCALE(dwPatch, &This->header.Locale);
 
     return S_OK;
 }
@@ -264,7 +264,7 @@ HRESULT IDirectMusicInstrumentImpl_CustomLoad(IDirectMusicInstrument *iface, ISt
         return DMUS_E_UNSUPPORTED_STREAM;
     }
 
-    This->regions = HeapAlloc(GetProcessHeap(), 0, sizeof(*This->regions) * This->pHeader->cRegions);
+    This->regions = HeapAlloc(GetProcessHeap(), 0, sizeof(*This->regions) * This->header.cRegions);
     if (!This->regions)
         return E_OUTOFMEMORY;