diff --git a/include/x3daudio.h b/include/x3daudio.h
index 0fd9a300927..26e2d1df728 100644
--- a/include/x3daudio.h
+++ b/include/x3daudio.h
@@ -97,6 +97,51 @@ typedef struct X3DAUDIO_DSP_SETTINGS {
 #define X3DAUDIO_CALCULATE_ZEROCENTER       0x00010000
 #define X3DAUDIO_CALCULATE_REDIRECT_TO_LFE  0x00020000
 
+#ifndef _SPEAKER_POSITIONS_
+#define _SPEAKER_POSITIONS_
+#define SPEAKER_FRONT_LEFT                  0x00000001
+#define SPEAKER_FRONT_RIGHT                 0x00000002
+#define SPEAKER_FRONT_CENTER                0x00000004
+#define SPEAKER_LOW_FREQUENCY               0x00000008
+#define SPEAKER_BACK_LEFT                   0x00000010
+#define SPEAKER_BACK_RIGHT                  0x00000020
+#define SPEAKER_FRONT_LEFT_OF_CENTER        0x00000040
+#define SPEAKER_FRONT_RIGHT_OF_CENTER       0x00000080
+#define SPEAKER_BACK_CENTER                 0x00000100
+#define SPEAKER_SIDE_LEFT                   0x00000200
+#define SPEAKER_SIDE_RIGHT                  0x00000400
+#define SPEAKER_TOP_CENTER                  0x00000800
+#define SPEAKER_TOP_FRONT_LEFT              0x00001000
+#define SPEAKER_TOP_FRONT_CENTER            0x00002000
+#define SPEAKER_TOP_FRONT_RIGHT             0x00004000
+#define SPEAKER_TOP_BACK_LEFT               0x00008000
+#define SPEAKER_TOP_BACK_CENTER             0x00010000
+#define SPEAKER_TOP_BACK_RIGHT              0x00020000
+#define SPEAKER_RESERVED                    0x7ffc0000
+#define SPEAKER_ALL                         0x80000000
+#endif
+
+#ifndef SPEAKER_MONO
+#define SPEAKER_MONO                    SPEAKER_FRONT_CENTER
+#define SPEAKER_STEREO                  (SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT)
+#define SPEAKER_2POINT1                 (SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT | SPEAKER_LOW_FREQUENCY)
+#define SPEAKER_SURROUND                (SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT | SPEAKER_FRONT_CENTER | SPEAKER_BACK_CENTER)
+#define SPEAKER_QUAD                    (SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT | SPEAKER_BACK_LEFT | SPEAKER_BACK_RIGHT)
+#define SPEAKER_4POINT1                 (SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT | SPEAKER_LOW_FREQUENCY | SPEAKER_BACK_LEFT | \
+                                         SPEAKER_BACK_RIGHT)
+#define SPEAKER_5POINT1                 (SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT | SPEAKER_FRONT_CENTER | SPEAKER_LOW_FREQUENCY | \
+                                         SPEAKER_BACK_LEFT | SPEAKER_BACK_RIGHT)
+#define SPEAKER_7POINT1                 (SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT | SPEAKER_FRONT_CENTER | SPEAKER_LOW_FREQUENCY | \
+                                         SPEAKER_BACK_LEFT | SPEAKER_BACK_RIGHT | SPEAKER_FRONT_LEFT_OF_CENTER | \
+                                         SPEAKER_FRONT_RIGHT_OF_CENTER)
+#define SPEAKER_5POINT1_SURROUND        (SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT | SPEAKER_FRONT_CENTER | SPEAKER_LOW_FREQUENCY | \
+                                         SPEAKER_SIDE_LEFT  | SPEAKER_SIDE_RIGHT)
+#define SPEAKER_7POINT1_SURROUND        (SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT | SPEAKER_FRONT_CENTER | SPEAKER_LOW_FREQUENCY | \
+                                         SPEAKER_BACK_LEFT | SPEAKER_BACK_RIGHT | SPEAKER_SIDE_LEFT  | SPEAKER_SIDE_RIGHT)
+#endif
+
+#define X3DAUDIO_SPEED_OF_SOUND             343.5f
+
 #define X3DAUDIO_HANDLE_BYTESIZE 20
 typedef BYTE X3DAUDIO_HANDLE[X3DAUDIO_HANDLE_BYTESIZE];