Custom practice mute for Trombone (Trumpet, Flugelhorn, etc.)

Sorry in advance for the mess, this is just a quick post with some bad pictures of a design that I made in 2022 and never 100% prepared for release. I just found it again and thought it would be a waste to not post it to the community in case someone could make use of it.

This is an OpenSCAD cusomizable mute I created from scratch but heavily inspired by PieterB's design PrintBone practice mute for Trumpet, (Bass) Trombone and Flugelhorn - customizable! and the reason why I flag it as a remix. Big props to him, check out his design!

I had some minor issues with his design, being unable to do 100% what I wanted and getting holes in my models due to the fact that, as far as I remember, his design could produce uneven wall thinness depending on the wall angle which I wasn't able to easily solve.

Since I'm usually open for a challenge and like to do my own thing I took his idea and started from scratch using some stuff that I did in the past, mainly may Bézier curve code I wrote for my Custom Stamp with Exchangeable Text model. This solution should produce even wall thickness throughout but may have some other drawbacks (e.g. different point of center within the wall).

As usual while tweaking and playing around over time I added more and more properties, debug features and examples, which adds more customization options etc. but may also ramp up the complexity and makes testing it for consistency pretty hard, so no guarantee for anything and I hope it's somehow usable.

I printed two mutes, one for my 70's Conn 48H and one for my old B&S small bore that has a bit of an unconventionally large 25cm (~9.84") bell, usually requiring bass trombone mutes.

In the OpenSCAD screenshot you should get a glimpse of the various properties and cross-section options I added. It has a fer example presets (details can be found in the code) and quadratic as well as cubic beerier curve support. It's not trivial to get into I reckon.

A way to start could be:

• Roughly measured the inner bell in 1cm steps.
• Render the measurements using the following code in the scad file: PolylineWPY10([202,159,125,102,84,71,63,58,54.2,51,48.2,45.7,43.4,41.6,40.3,39.2,38.2]/2); which will show the bell curve (flat).
• Check both the bell debug and bell debug flat properties to project the bell curve (flat) using the Bézier control points defined within the bell properties section.
• Tweak the control points until they roughly match the (usually a bit bumpy) measured curve to define a smooth reference bell.
• Start playing around with the mute properties etc. to create a prototype STL.

Regarding the STLs note that the ones I uploaded might not be perfect or generic in any way. Hole at the bottom might need some tweaking so be warned that simply printing these might not give you the result you want!

• Brass Mute v0.4 - SB Narrow 2 - Tenor Trombone
  • Printed for my Conn 48H
  • The air whole might need tweaking depending on desired resistance vs. noise level.
• Brass Mute v0.4 - SB Narrow 2 - Base Trombone
  • Printed for my 25cm bell B&S
  • My B&S is actually a tenor not a Base trombone but this mute is to larger than the above and might es well fit a bass trombone. I have to use regular bass trombone mutes for the B&S since tenor simply don't fit (just vanish inside :-P).
  • The air whole might need tweaking depending on desired resistance vs. noise level (in this case it's pretty narrow as far as I remember, not playing my B&S currently).
• All other STLs are UNPRINTED UNTESTED EXAMPLES ONLY based on the demo profiles I added to the OpenSCAD file (mostly ideas or prototypes I played around with).