Examples: Fix transparency issue

examples/webaudio_orientation.html

@@ -151,9 +151,7 @@
 		mesh.receiveShadow = true;
 		scene.add( mesh );
 
-		var grid = new THREE.GridHelper( 50, 50, 0x000000, 0x000000 );
-		grid.material.opacity = 0.2;
-		grid.material.transparent = true;
+		var grid = new THREE.GridHelper( 50, 50, 0x444444, 0x444444 );
 		scene.add( grid );
 
 		//