Home-Made IEMs
Sep 15, 2021 at 7:31 AM Post #13,336 of 13,621

CBTlover223

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Hello, how do I determine which frequencies a driver is best suited for? I am trying to build my first CIEM, but I am not sure which drivers to choose. I am currently considering the SWFK-31736 for the tweeter and the HODVTEC-31618 for the woofer but I am not sure if I should choose a driver dedicated to the mids. Any help would be greatly appreciated.

Also, can I use software like vituixCAD to get a rough idea of the frequency response of the completed IEM?
 
Sep 16, 2021 at 12:04 AM Post #13,339 of 13,621

ohige

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This is my first post.
I did a lot of testing to make an IEM.

I am currently considering the SWFK-31736 for the tweeter and the HODVTEC-31618 for the woofer but I am not sure if I should choose a driver dedicated to the mids.
If you don't add a mid, you may get a dip at 2k-3kHz. This can result in loss of sound transparency.
However, 3WAY IEMs are difficult to adjust. The units affect each other electrically and mechanically. In other words, the damper attached to the woofer also affects the tweeter. The difficulty level is different between 2WAY and 3WAY. 2WAY is recommended for the first production.

Also, can I use software like vituixCAD to get a rough idea of the frequency response of the completed IEM?
In order to measure the frequency characteristics, it is good to have a personal computer, a microphone, a PVC tube, and a kneaded eraser.
Use a kneaded eraser to fill the gap between the unit or IEM and the PVC tube.
I am using REW for measurement.
It does not give exactly the correct measurements, but it can be compared to other IEMs. I think you can make the measurements you need.

I haven't been allowed to post photos yet.:sob:
 
Sep 16, 2021 at 1:19 AM Post #13,340 of 13,621

ohige

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Hello everyone.
I learned a lot from this forum and made an IEM.
I am grateful to everyone who shared a lot of knowledge.

I'm not good at English, so I use google translate. I'm sorry if there is strange English.

I did a lot of experiments, tests, measurements and auditions to make an IEM.
The model version of the IEM is 12, and I'm finally proud of the IEM I like.

I made it as follows.

1) Create impressions.
2) 3D scan with iphone (Trnio).
3) Mold the 3D model with meshmixer.
4) Create a part to attach the face plate with FUSION 360 and convert it to STL.
5) Synthesize the impressions model and the face plate model with meshmixer.
6) Design the sound path part with FUSION 360 and subtract it from the external model.
7) Design the face plate with FUSION 360.
8) Print the model with a 3D printer (ELEGOO MARS 2 Pro).
9) Lacquer the printed material.
10) Adjust the network and damper while incorporating the unit and performing measurement (REW).
11) Make a face plate, cover the IEM and it's done!

model: IEM-012 is 10BA. All units are from langzhisheng (AliExpress).

EJ-30029 x 1 (≒ CI-22955 x 2) + Red Dumper (2200 ohm)
4.7uF + FWEK-31785 x 1 (≒ DWFK-31785 x 2) + Brown dumper (1000ohm) x 2
0.68uF + FWEK-31718 x 1 (≒ SWFK-31736 x 2)

I am using Rubycon PMLCAP for the capacitor. SMD type small film capacitor.
The sound is very clear. I have the illusion that my ears have improved. The treble (6kHz and above) is weak in the frequency response measurement, but it doesn't hurt because of that. I like the KZ ZAX and ZAS sounds, but the IEM-012 sounds better than them.
Since the impedance is low (10 ohm), a high-performance amplifier is required. A small amount of electrical noise becomes a sound. Also, the output impedance of the amplifier must be low enough. I am using the voltage follower circuit of THS4631.

The face plate can be replaced. I made different designs of faceplates using various techniques. I can exchange it depending on the mood of the day.

I have done a lot of experiments so I have gained experience and knowledge. I would like to share that experience with you.

s_IMG_8279.jpg

Sunburst!
s_IMG_8470.jpg

The Metal
s_IMG_8581.jpg

Aurora
s_IMG_8583.jpg

Racing
s_IEM-012.jpg

IEM-012 Frequency characteristic
s_IEM-012_imp.jpg

IEM-012 Impedance characteristics
s_iem_012BA v9.jpg

IEM-012 Sound path design
s_IMG_8573.jpg

Inside IEM-012. I use a kneaded eraser.
s_IMG_8587.jpg

Various IEMs(1DD+2BA,1DD+7BA,8BA,6BA etc...)
s_IMG_8585.jpg

Replaceable face plate
s_IMG_8588.jpg

Jigs and microphones for testing.
 
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Sep 16, 2021 at 2:06 AM Post #13,342 of 13,621

ohige

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Hello, Looks very good. I wanna to know how the faceplate firmly attached to the shell ? Can you tell more about this. Thanks !
All IEMs have a common shape for the faceplate mounting area.
The face plate has a convex part that fits into the IEM.
Use a kneaded eraser when fitting to make it more difficult to remove. The kneaded eraser is a little sticky (but easy to peel off) so you can put it on and take it off again and again.


s_common shape.jpg

Synthesize common shapes.
s_iem_012BA v9 (2).jpg

The part where the face plate fits is all the same shape.
s_iem_CAP_11 v1.jpg
 
Sep 16, 2021 at 3:25 AM Post #13,343 of 13,621

Xymordos

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The replaceable faceplate is really cool! I need to learn how to use Fusion 360 too ><
 
Sep 16, 2021 at 3:47 AM Post #13,344 of 13,621

ohige

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The replaceable faceplate is really cool! I need to learn how to use Fusion 360 too ><
Thank you!

It's hard to explain all the features of the FUSION 360, but I first created a common sketch. I imported the model data on the left and the model data on the right, which was inverted, and drew a common geometric figure. All shells and faceplates are based on this sketch.

s_iem_CAP_11_sc1.jpg


The technique of nail art is very helpful for how to make a face plate.
Two additional faceplates will be completed today or tomorrow. I will show you the photo again when it is completed.

I don't use glue on it. Only a kneaded eraser. I love the kneaded eraser.:smile:
All my IEMs are ready to be disassembled. If I don't like the sound, I can disassemble it and put the unit in another shell.
It is very convenient because it is easy to change the capacitor and replace the wiring for adjustment.
 
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Sep 16, 2021 at 4:08 AM Post #13,345 of 13,621

Xymordos

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Thank you!
The technique of nail art is very helpful for how to make a face plate.
Two additional faceplates will be completed today or tomorrow. I will show you the photo again when it is completed.

I don't use glue on it. Only a kneaded eraser. I love the kneaded eraser.:smile:
All my IEMs are ready to be disassembled. If I don't like the sound, I can disassemble it and put the unit in another shell.
It is very convenient because it is easy to change the capacitor and replace the wiring for adjustment.

Kneaded eraser...do you mean blutak? o.O
 
Sep 16, 2021 at 4:17 AM Post #13,346 of 13,621

mattmatt

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All IEMs have a common shape for the faceplate mounting area.
The face plate has a convex part that fits into the IEM.
Use a kneaded eraser when fitting to make it more difficult to remove. The kneaded eraser is a little sticky (but easy to peel off) so you can put it on and take it off again and again.


s_common shape.jpg
Synthesize common shapes.
s_iem_012BA v9 (2).jpg
The part where the face plate fits is all the same shape.
s_iem_CAP_11 v1.jpg
Great! How did you manage to create the chamber/driver holder? Is it from a hollow shell?
 
Sep 16, 2021 at 4:39 AM Post #13,348 of 13,621

ohige

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Great! How did you manage to create the chamber/driver holder? Is it from a hollow shell?
Place the unit model on the external model.
iem_012BA _001.png


Create a sound path model.
iem_012BA_002.png


Subtract the sound path model from the external model.
iem_012BA_003.png


The unit model is made a little larger (0.1mm) than the actual one, so it feels like pushing the unit weakly. When assembling, fill the gap with a kneaded eraser to prevent sound leakage.

Does this explanation match?
 
Sep 16, 2021 at 4:49 AM Post #13,350 of 13,621

Aldo40

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Place the unit model on the external model.
iem_012BA _001.png

Create a sound path model.
iem_012BA_002.png

Subtract the sound path model from the external model.
iem_012BA_003.png

The unit model is made a little larger (0.1mm) than the actual one, so it feels like pushing the unit weakly. When assembling, fill the gap with a kneaded eraser to prevent sound leakage.

Does this explanation match?
First of all, it’s a great job , congratulations:wink: I don’t really understand the sticking with rubbing gum. Why don’t you create the locations in the full direct shell under 360 fusion? It would save you the trouble of assembling and pasting
 

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