READ: This is still purely a theory and has not been tested.
I’m just blowing my own horn here, but I believe I have thought of a way to make a custom IEM sleeve cheap (given that you have access to the proper hardware required).
What is required is patience, a 3D printer, a camera, proper lighting, a decent~very good desktop computer, an intermediate knowledge of 3D modeling, a 3D reconstruction program, a 3D modeling program, silicone, and some resin (or any other material that can harden within a mold). I am very sorry for the long list, but most of the things needed can be obtained for fairly cheap, with a 3D printer and a computer being the exceptions.
Phase 1: Ear Impressions.
Step 1: Get ear impressions from a nearby hearing aid store or IEM store.
Step 2: Bring them home and find a way of suspending them in mid-air.
Step 3: Take many pictures and upload them to your computer.
Step 4: Using a 3D reconstruction tool of your choice, make a 3D model of your ear impressions. such (Meshroom by Alicevision.org is free and decently accurate, with the only caveat being that it is demanding for the computer)
Step 5: Using a 3D modeling tool of your choice, delete all unnecessary parts of the 3D model. (Fusion 360 is free for “entrepreneurs”)
Step 6: 3D print the ear impressions.
Step 7: Sand and finish the 3D printed ear impressions.
Step 8: Mix the silicone in a container and stick the ear impressions in them.
Step 9: Pull the ear impressions out when the silicone is finished hardening.
Phase 2: IEMs
Step 1: Find your IEMS of choice.
Step 2: Suspend them in mid-air by the outside of the shell(the part that isn’t touching your ear).
Step 3~7 are the same as Phase 1, but with the IEMs instead of the ear impressions.
Step 8 and 9 are the same as Phase 1.
Phase 3: The Sleeve
Step 1: Mix up the resin(or any other material of your choice).
Step 2: Pour the resin in the mold from Phase 2. If you have access to a vacuum chamber, now is the time to use it.
Step 3: Take the finished IEM replica out when the resin is finished hardening.
Step 4: Glue a water-soluble disk that is slightly large than the diameter of the IEM bore to the end of the bore of the replica. (This is to put an O-ring in so the IEM doesn’t come out)
Step 9: Glue a small cylinder the same diameter as the IEM bore to the other end of the disk (this is so that you will actually hear something).
Step 5 and 6 are the same as steps 1 and 2. Make sure the resin is okay to put in your ear.
Step 7: Place the IEM replica with the disk attached in the not-yet cured resin.
Step 8: When the resin is cured, take it out of the mold.
Step 9: Take the IEM replica and cylinder out.
Step 10: Wash the inside of the sleeve to create a space for the O-ring.
Step 11: Put an O-ring inside.
Step 12: Put the IEMs in and have a listen.
I am very sorry for such a long post.
Please point out any possible flaws in my plan.
I’ll make sure to update this post when I do this myself.
Feel free to do this yourself.
Thank you for reading!