there are 2 separate whistle chambers one on each side. maybe you added support or infil. no support should be used and only infill where needed may be checked. mine only used infill in the top of large flotation chamber. only issue mine had was last 4 layers of print it made a rough ring/crown instead of just flat for some reason and it was not shown in G-code. works great just have to blow hard.printed on my Solidoodle 2 using 2mm layers ABS. plan to do in glow in dark ABS for easy location and to use as night marker by twirling it by coed creating glowing circle to be seen far off in rescue. wish it would Whistle while twirling as well.