There are a lot of reasons why a 3D-printed whistle might not work in some way, but generally they can be reduced to a few main tuning issues to check

• Flow percentage issue (generally too little flow)
• Pressure advance issue
• bridging layers are not solid, allowing air to escape the chamber(s)

I find it helpful to understand how a whistle works in order to troubleshoot what a possible issue is.

1. Air enters via the airway
   1. The air accelerates, usually by gradually making the airway smaller
2. Air hits the “blade”, creating a fluttering effect
3. That fluttering, along with the air building up pressure in the chamber, makes the air inside the chamber vibrate, which creates sound

• The airway - too restrictive or an obstructed path not allowing air to accelerate
• The blade - not sharp/uniform enough to create fluttering
• The chamber - air escaping and not building pressure

From the above, we should check

• If the airway has stringing or similar in it
  • You always want to “paint on” seams away from any of the above components
• If the blade is not sharp
  • Points to a Pressure Advance, cooling, or flow issue
• If there are holes in the chamber walls or walls of the whistle, allowing air to escape
  • Could be flow, seam, or retraction issue