Cup mute for trumpets, with an adjustable distance from the cup to the bell to vary your sound.

Print the Body and Cup from something ridgid, like PLA or ABS. Print 3 pads and 1 bottom cover from TPU. No supports. For the TPU parts, use minimal wall thicknesses, 5% gyroid infill to keep them squishy. For the body and cup use 6 perimeters for strength and your choice of infill (there's not a lot of infill since it's hollow).

You will also need a sheet of 1mm Felt (thicker could work, but you'll need to tweak the CAD file to open up the spacing to allow for it), and some 3m contact adhesive sheets.

To assemble, cut a strip of felt and an equal size piece of contact adhesive to fit over the bottom collar. Stick down the adhesive, peel back the protective paper, and then stick the felt down to it, trimming it to fit. Then do the same to the inside of the collar for the cup part.

Take the bottom cover and fit it over the bottom of the mute. The pads have tabs on the top and bottom that fit in the slots in the receivers at the top of the mute. I also used a small piece of contact adhesive under both the bottom cover and the pads to make sure they stay put.