diff --git a/dlls/x3daudio1_0/x3daudio1_0.spec b/dlls/x3daudio1_0/x3daudio1_0.spec
index 0d6caa0ccfa..b9ba1c4fb41 100644
--- a/dlls/x3daudio1_0/x3daudio1_0.spec
+++ b/dlls/x3daudio1_0/x3daudio1_0.spec
@@ -1,2 +1,4 @@
-@ cdecl X3DAudioCalculate(ptr ptr ptr long ptr)
-@ cdecl X3DAudioInitialize(long float ptr) LEGACY_X3DAudioInitialize
+@ stdcall -arch=i386 _X3DAudioCalculate@20(ptr ptr ptr long ptr) LEGACY_X3DAudioCalculate
+@ stdcall -arch=i386 _X3DAudioInitialize@12(long float ptr) LEGACY_X3DAudioInitialize
+@ stdcall -arch=!i386 X3DAudioCalculate(ptr ptr ptr long ptr) LEGACY_X3DAudioCalculate
+@ stdcall -arch=!i386 X3DAudioInitialize(long float ptr) LEGACY_X3DAudioInitialize
diff --git a/dlls/x3daudio1_1/x3daudio1_1.spec b/dlls/x3daudio1_1/x3daudio1_1.spec
index 0d6caa0ccfa..b9ba1c4fb41 100644
--- a/dlls/x3daudio1_1/x3daudio1_1.spec
+++ b/dlls/x3daudio1_1/x3daudio1_1.spec
@@ -1,2 +1,4 @@
-@ cdecl X3DAudioCalculate(ptr ptr ptr long ptr)
-@ cdecl X3DAudioInitialize(long float ptr) LEGACY_X3DAudioInitialize
+@ stdcall -arch=i386 _X3DAudioCalculate@20(ptr ptr ptr long ptr) LEGACY_X3DAudioCalculate
+@ stdcall -arch=i386 _X3DAudioInitialize@12(long float ptr) LEGACY_X3DAudioInitialize
+@ stdcall -arch=!i386 X3DAudioCalculate(ptr ptr ptr long ptr) LEGACY_X3DAudioCalculate
+@ stdcall -arch=!i386 X3DAudioInitialize(long float ptr) LEGACY_X3DAudioInitialize
diff --git a/dlls/x3daudio1_2/x3daudio1_2.spec b/dlls/x3daudio1_2/x3daudio1_2.spec
index 0d6caa0ccfa..b9ba1c4fb41 100644
--- a/dlls/x3daudio1_2/x3daudio1_2.spec
+++ b/dlls/x3daudio1_2/x3daudio1_2.spec
@@ -1,2 +1,4 @@
-@ cdecl X3DAudioCalculate(ptr ptr ptr long ptr)
-@ cdecl X3DAudioInitialize(long float ptr) LEGACY_X3DAudioInitialize
+@ stdcall -arch=i386 _X3DAudioCalculate@20(ptr ptr ptr long ptr) LEGACY_X3DAudioCalculate
+@ stdcall -arch=i386 _X3DAudioInitialize@12(long float ptr) LEGACY_X3DAudioInitialize
+@ stdcall -arch=!i386 X3DAudioCalculate(ptr ptr ptr long ptr) LEGACY_X3DAudioCalculate
+@ stdcall -arch=!i386 X3DAudioInitialize(long float ptr) LEGACY_X3DAudioInitialize
diff --git a/dlls/xaudio2_7/x3daudio.c b/dlls/xaudio2_7/x3daudio.c
index 5bc7c8473c6..240cd5c101c 100644
--- a/dlls/xaudio2_7/x3daudio.c
+++ b/dlls/xaudio2_7/x3daudio.c
@@ -63,8 +63,13 @@ HRESULT CDECL X3DAudioInitialize(UINT32 chanmask, float speedofsound,
 #endif /* XAUDIO2_VER >= 8 */
 
 #ifdef X3DAUDIO1_VER
+#if X3DAUDIO1_VER <= 2
+void WINAPI LEGACY_X3DAudioInitialize(UINT32 chanmask, float speedofsound,
+        X3DAUDIO_HANDLE handle)
+#else
 void CDECL LEGACY_X3DAudioInitialize(UINT32 chanmask, float speedofsound,
         X3DAUDIO_HANDLE handle)
+#endif
 {
     TRACE("0x%x, %f, %p\n", chanmask, speedofsound, handle);
     F3DAudioInitialize(chanmask, speedofsound, handle);
@@ -72,9 +77,15 @@ void CDECL LEGACY_X3DAudioInitialize(UINT32 chanmask, float speedofsound,
 #endif /* X3DAUDIO1_VER */
 
 #if XAUDIO2_VER >= 8 || defined X3DAUDIO1_VER
+#if defined(X3DAUDIO1_VER) && X3DAUDIO1_VER <= 2
+void WINAPI LEGACY_X3DAudioCalculate(const X3DAUDIO_HANDLE handle,
+        const X3DAUDIO_LISTENER *listener, const X3DAUDIO_EMITTER *emitter,
+        UINT32 flags, X3DAUDIO_DSP_SETTINGS *out)
+#else
 void CDECL X3DAudioCalculate(const X3DAUDIO_HANDLE handle,
         const X3DAUDIO_LISTENER *listener, const X3DAUDIO_EMITTER *emitter,
         UINT32 flags, X3DAUDIO_DSP_SETTINGS *out)
+#endif
 {
     TRACE("%p, %p, %p, 0x%x, %p\n", handle, listener, emitter, flags, out);
     F3DAudioCalculate(