diff --git a/src/sound.cpp b/src/sound.cpp
--- a/src/sound.cpp
+++ b/src/sound.cpp
@@ -255,7 +255,7 @@ void SndPlayTileFx(SoundID sound, TileIn
 	/* emits sound from center of the tile */
 	int x = min(MapMaxX() - 1, TileX(tile)) * TILE_SIZE + TILE_SIZE / 2;
 	int y = min(MapMaxY() - 1, TileY(tile)) * TILE_SIZE - TILE_SIZE / 2;
-	uint z = (y < 0 ? 0 : GetSlopePixelZ(x, y));
+	int z = (y < 0 ? 0 : GetSlopePixelZ(x, y));
 	Point pt = RemapCoords(x, y, z);
 	y += 2 * TILE_SIZE;
 	Point pt2 = RemapCoords(x, y, GetSlopePixelZ(x, y));