Recently I ran across an article about Helmholtz Resonators and I just had to explore a bit further. The great thing about 3D printing is that I was quickly able to design and print a couple of models to try them out for myself.

The prints included here show an estimated resonance frequency based upon this calculator :

• https://www.omnicalculator.com/physics/helmholtz-resonator

An online tone generator made it possible to cycle through a range of audio frequencies and experience the resonance first hand :

• https://www.szynalski.com/tone-generator/

It is interesting to operate the tone generator while not looking at the screen, in order to detect the resonant frequency purely by listening - you will see just how close to the predicted resonant frequency the models actually are. The two models shown here have [calculated] resonant frequencies of 1100Hz and 2500Hz - these frequencies should be easily reproduced by most audio systems.

Note : The small end that fits into the ear has edges that may be a bit sharp; I “softened” the edges with a little bit of sanding.

Print Instructions

Print in PLA using the 3mf file provided; otherwise :

• 0.3mm layer height
• brim
• 0% infill
• 2 perimeters

CAD

The OnShape 3D CAD files for this are here :

https://cad.onshape.com/documents/c4de52cb90e7e656aada2e2e/w/264ef042a389474875bdb9d8/e/0505383a4152896c2c087687?renderMode=0&uiState=6578fd646ebe550bc745825a