Parametric Two-tone Heart Whistle

Yet another 3D printed whistle. There are a couple other heart-shaped ones but I wanted a two-tone version for that warbling effect that makes the sound carry better.

I don't have a proper decibel meter but my Apple Watch claims all of the different versions of these produce in the range of 100-125 dB. The different sizes are tuned as good as I can for ideal performance.

I've provided a few variations on the following:

• Size:

  • 30x30

  • 35x35

  • 40x40 (this is my favorite)

  • 50x50 (long bridges require a well-tuned printer)

• Lanyard Ring:

  • Center

  • Side

• Thickness

  • 3mm

  • 5mm

If you are interested in other sizes, I encourage you to check out the parametric settings linked below.

Updates

• 2026-02-04

  • Slight change to design to encourage slicer to place seams out of the way of important airflow

  • Update docs about seam placement

• 2026-02-02

  • Regenerate all models with small changes to geometry to improve bridges in OrcaSlicer

  • Add 35x35 variants

Recommend print settings

• Nozzle size: 0.4mm

• Layer Height: 0.2mm (important for bridge placement)

• Infill: 0%

• Seam position: Aligned (see below)

• For best appearance, I also recommend adjusting the Fill Angle to 90° so the top/bottom layers run vertically.

For the 5mm versions, you may also find it helpful to set the Bridging Angle to 1° (it should be 0° but that gets interpreted as "auto") so bridges run as close to perpendicular across the airways as possible (3mm versions seem to work fine with the default).

Seam Placement

This model has been designed to encourage the slicer to place seams away from where they might interfere with airflow. However, it's still worth checking the preview to ensure that seams are not placed anywhere near the fipple, especially at the tip of the blade or on the bridges over it. This screenshot shows ideal seam placement:

Parametric

Like most of my models, you can find the parametric CAD here at Onshape. I've provided some default configurations that match what are available here but should you wish to go down the rabbit hole of optimizing sound quality, there are a plethora of settings for advanced users.

Tips:

• You will need a free account in order to export STLs.

• Not every combination of settings will produce a valid whistle. If things don't render properly, try changing other settings until they do.

• Increasing Window Length will make the whistle louder when you blow harder, but not work well when blowing softly. A shorter length will produce a whistle that can blow quietly but will work poorly when you blow hard.

• Feel free to use my CAD as an example for making your own whistles