diff --git a/src/net/torvald/terrarum/modulebasegame/BuildingMaker.kt b/src/net/torvald/terrarum/modulebasegame/BuildingMaker.kt
index 962070521..5989f33ea 100644
--- a/src/net/torvald/terrarum/modulebasegame/BuildingMaker.kt
+++ b/src/net/torvald/terrarum/modulebasegame/BuildingMaker.kt
@@ -919,6 +919,15 @@ class YamlCommandNewFlatTerrain : YamlInvokable {
         val timeNow = System.currentTimeMillis() / 1000
         ui.gameWorld = GameWorld(90*12, 90*4, timeNow, timeNow)
 
+        // remove null tiles
+        for (y in 0 until ui.gameWorld.height) {
+            for (x in 0 until ui.gameWorld.width) {
+                ui.gameWorld.setTileWall(x, y, Block.AIR, true)
+                ui.gameWorld.setTileTerrain(x, y, Block.AIR, true)
+            }
+        }
+
+        // fill with stuffs
         for (y in 0 until ui.gameWorld.height) {
             ui.gameWorld.setTileWall(0, y, Block.ILLUMINATOR_RED, true)
             ui.gameWorld.setTileWall(ui.gameWorld.width - 1, y, Block.ILLUMINATOR_RED, true)
diff --git a/src/net/torvald/terrarum/modulebasegame/gameactors/ActorLobbed.kt b/src/net/torvald/terrarum/modulebasegame/gameactors/ActorLobbed.kt
index a322b687c..88e211ebf 100644
--- a/src/net/torvald/terrarum/modulebasegame/gameactors/ActorLobbed.kt
+++ b/src/net/torvald/terrarum/modulebasegame/gameactors/ActorLobbed.kt
@@ -40,7 +40,7 @@ open class ActorLobbed(throwPitch: Float) : ActorWithBody() {
         super.updateImpl(delta)
         if (!soundFired) {
             soundFired = true
-            val amp = 1.65 * (pitch - 0.495)
+            val amp = 6.0 * (pitch.sqrt() - 0.495)
             startAudio(whooshSound, amp)
         }
     }