Four tone whistle

all credit goes to SelfTaughtStu_472555

This whistle design was born from my experiment with a 3D-printed whistling bomb, intended to be dropped from a drone. I took inspiration from the "Whisbang RC whistling bombs" and created a body with four chambers, hoping each one would produce interesting sound during free fall. Unfortunately, even from a 500m drop, it didnt produce any sound. 
However, when used like a traditional whistle (blowing into it) it works and its very loud, so I redesigned it to be a whistle instead.

Using the Spectroid Android app, I measured the frequencies and loudness of each tone. Based on spectrum analysis assisted by ChatGPT, the results are approximately:

2769 Hz at -34 dB

3393 Hz at -31 dB

4447 Hz at -25 dB

6211 Hz at -18 dB

I wasn't even blowing very hard during the test, since the sound was already quite intense. With more forceful blowing, it could likely get much louder.

While 6211Hz was technically the loudest in the spectrum (at -18 dB), it sounded low to me. If I block the other three chambers, it sounds way louder, suggesting its probably a design flaw.

This whistle still sounds off even with light airflow, so I recommend starting gently when testing it for the first time.

I printed it without supports with 0.2mm layer height and 50mm/s speed and even on Ender 3 it was able to print it without a problem.

Im currently learning more about acoustic design and chamber tuning, and I plan to release more whistle models soon with better frequency control and tuning.