diff --git a/src/modules/audio/wrap_Audio.cpp b/src/modules/audio/wrap_Audio.cpp
index 9a9033e26..a5758326c 100644
--- a/src/modules/audio/wrap_Audio.cpp
+++ b/src/modules/audio/wrap_Audio.cpp
@@ -142,7 +142,7 @@ namespace audio
 		float v[3];
 		v[0] = (float)luaL_checknumber(L, 1);
 		v[1] = (float)luaL_checknumber(L, 2);
-		v[2] = (float)luaL_checknumber(L, 3);
+		v[2] = (float)luaL_optnumber(L, 3, 0);
 		instance->setPosition(v);
 		return 0;
 	}
@@ -188,7 +188,7 @@ namespace audio
 		float v[3];
 		v[0] = (float)luaL_checknumber(L, 1);
 		v[1] = (float)luaL_checknumber(L, 2);
-		v[2] = (float)luaL_checknumber(L, 3);
+		v[2] = (float)luaL_optnumber(L, 3, 0);
 		instance->setVelocity(v);
 		return 0;
 	}
diff --git a/src/modules/audio/wrap_Source.cpp b/src/modules/audio/wrap_Source.cpp
index 901876468..574d7ba1b 100644
--- a/src/modules/audio/wrap_Source.cpp
+++ b/src/modules/audio/wrap_Source.cpp
@@ -121,7 +121,7 @@ namespace audio
 		float v[3];
 		v[0] = (float)luaL_checknumber(L, 2);
 		v[1] = (float)luaL_checknumber(L, 3);
-		v[2] = (float)luaL_checknumber(L, 4);
+		v[2] = (float)luaL_optnumber(L, 4, 0);
 		t->setPosition(v);
 		return 0;
 	}
@@ -143,7 +143,7 @@ namespace audio
 		float v[3];
 		v[0] = (float)luaL_checknumber(L, 2);
 		v[1] = (float)luaL_checknumber(L, 3);
-		v[2] = (float)luaL_checknumber(L, 4);
+		v[2] = (float)luaL_optnumber(L, 4, 0);
 		t->setVelocity(v);
 		return 0;
 	}
@@ -165,7 +165,7 @@ namespace audio
 		float v[3];
 		v[0] = (float)luaL_checknumber(L, 2);
 		v[1] = (float)luaL_checknumber(L, 3);
-		v[2] = (float)luaL_checknumber(L, 4);
+		v[2] = (float)luaL_optnumber(L, 4, 0);
 		t->setDirection(v);
 		return 0;
 	}