Custom In-ear monitors (CIEM), widely used by musicians and performers. These earphones are custom fitted to the individuals ear for superior isolation and comfort.

It began when I wanted a pair of CIEM, just to realize that the cost for one has well surpassed my budget. So, I wondered if it's possible to make one myself and turns out there's a big community for DIY CIEMs! aka DIEM(DIY- IEM)

This Instructables will document the process of building your own CIEM at a fraction of the price :D

Step 1: Tools, Materials and Some Literature

The tools and material will vary from each individuals preference.

This would be based on my quad driver CIEM

These are the general tools needed:

-Soldering iron
-Plasticine
-Blade
-Rotary tool

Materials
Electronics:
-Knowles GV-32830 (Quad Driver)
-Knowles BF-1861 (Green Dampener)
-Knowles BF- 1921 (Red Dampener)
-Litz wire
-2*3mm PVC sound tube
-1*2mm PVC sound tube
-Two pin 0.78mm female jack
-IEM wire

Shell:

UV resin
UV lacquer
Ear Impressions
Paraffin Wax
Little Container
Translucent silicone mold
UV light chamber
Dye

Note on impressions:
Making your own Impressions can cause potential risk of injury and deafness. It is suggested to seek an audiologist to do the impressions professionally. If you are to make your own, ensure that ear dams are used.

Note on Drivers:
The drivers used are already pre-made so there is no fuss on doing your own crossovers etc.
Alternatives and its suggested dampers.

Dual drivers:

Knowles GQ-30783, White damper

Knowles HE-31751, Brown damper on Tweeter, Red on Woofer

Triple Drivers

Knowles GK-31732, Green damper on Tweeter, Red on Woofer

Quad Drivers

Knowles GV-32830, Green damper on Tweeter, Orange or Red on Woofer

It is recommended to have a damper distance of 5mm for the tweeter and 7mm for the woofer as a starting point.

Here is a comprehensive guide on DIY CIEMs by user: Furco from head-fi.org : Click Here

Step 2: Getting Your Impressions

I got my impressions done by an audiologist as the risk and cost for making the impressions by myself does not justify itself and I have a relatively small ear. But anyways here's a guide on impressions by AAW, a CIEM company based in Singapore. Images are by AAW and I do not own any of them.

Notes:

It is recommended to use a biting block as this allows better movement of the jaw.
Impressions have to pass the second bend of the canal

In picture 4, green indicates a good impression and grey lacking details

Step 3: Preparing Your Impressions to Shape

I used a rotary tool and a blade to shape my ear impression. Ensure that the other surface is flattened.

After shaping it, clean it up and you can test fit by putting it back in your ear.

The ear canal at the second bend is highly sensitive so it's usually excluded.

Another good examples of how ear impressions are cut @ Post #3991(home-made IEMs) page 267 at headfi shows user: ForceMajeure's ear impression and user: Piotrus-g from CIEM company, Custom Art based in Poland indicating how impressions are cut.

Step 4: Making Negative Mold of Impressions

Start by heating up some Paraffin Wax in a little tin until liquid and dip the impression for a few seconds and let dry, and then repeat again with a total of two light coatings. (or just one or completely exclude depending on preference) This is just to ensure a smooth surface, if it is too thick it might hurt or not fit well

I bought these little containers that allows the other end to be opened.

Place the impression at the centre. Heat up the silicone to temperature (differs between types, some uses a two part mixture to make the silicone mold). Slowly pour the silicone in to avoid bubbling. Allow it to settle and harden

Step 5: Preparing the Balanced Armature Receivers

Solder the litz wire to the terminals. Don't be afraid it's actually not that hard! and then the other end to the female jacks. The tips of the female jacks can be trimmed to length.

Cut out the tubing for the dampeners.
x4 7mm 2*3mm tube to insert the dampeners

x2 5mm 1*2mm for the tweeters

x2 7mm 1*2 mm for the woofer

x4 3inch 1*2mm for the excess to bore

Set the dampeners vertically on the table and push the tube in. It can be further pressed in with your nails or a drill bit of a larger diameter can be used to push it in. The damper filter can be rather fragile so do be careful while handling

It is recommended to have a damper distance of 5mm for the tweeter and 7mm for the woofer as a starting point.You can play around with its position for different sound signatures.

Step 6: Creating the Shell

Start by pouring in the UV resin to the negative mold(colloid). Place a black cover on the top to restrict UV light from flowing through as you only want the sides to be cure, making a hollow shell.

Insert the mold into a UV chamber and let sit for about 1-3 minutes, varies on preferred thickness and light chamber. I like to have thin shells as they are easier to fit drivers if you have small ears. My cure time is about 1 minutes
Pour out excess, do it slowly and allow all to fully drip out. Then put it back and allow it to cure again for about 2-4 mins
Remove it from the colloid and putting using tweezers, avoid touching it as the surface is still tacky. Put it in a glycerin bath and cure it again while the shell is in the bath. Remove the shell and clean it up with water and some isopropyl alcohol.

And you are good to go.

*Cure time varies for everyone*

Step 7: Installing Your Drivers

Sand down your shells and making sure the faceplate surface is flat
Start by drilling the holes for the tubes on your shell and grinding a slot for the connectors
run the tube in first
Attach tube to drivers
Glue drivers to tube
Pull the tube down in place
Set drivers in place and putting drops of UV resin where the driver touches the wall of the shell and cure it to hold it in place
Place the connector in its position and some drops of UV resin and cure to hold it in place
You can test them out now at this point

Step 8: Faceplate and Finishing It Up.

Proceed by covering it with a faceplate (wood, vinyl, metals etc) or make a layer of UV resin on a piece of glass or non stick paper place it over the shell and attaching them in place with more UV resin and cure. Trim the excess away and sand the entire shell down. Followed by a layer of UV lacquer and rotate the shell as it cures.

And you are done!

Step 9: Parts List ~ish

Here are links to where I get my materials.

IEM list.txt
Download

Step 10: Special Thanks

Special thanks to the people of headfi (home-made-iems) and reddit r/DIEMs which have provided many useful guidance and information allowing me to build this. Be sure to check them out to seek for more help if needed.