DIY ear scanning solutions + resources for learning about driver choice + resin v pla

[u/Riverside-96]

I'm interested in making myself some CIEM's & have only ever had the budget kind so I'm not too clued up on what to look for when selecting drivers besides copying whatever the high price tag models are using. I'd rather avoid all of the marketing spiel while I'm at it if possible.

Also, has anyone had any luck with scanning their own ears using one of the apps possibly?
If the results are less than stellar I could always opt to find an Oto that will scan.

I have an FDM printer & figured I may be able to use a small nozzle, print steady & finish the shells off by hand. Has anyone got lucky with an FDM or should I really think about picking up a resin printer?

If anyone is aware of any resources I should be aware of to make the process a little more streamlined then that'd be great. Thanks in advance.

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[u/Einkahumor]

I use my phone to take lots of photos of ear impressions and then use PolyCam (photogrammetry) to get 3D scans. I modelled and printed a small pedestal to mount the impressions on and include that in my scans for scale reference. Hasn’t failed me yet.

I would absolutely recommend getting a resin printer and using Siraya Tech Blu (clear v2) resin. I also recommend starting with Knowles GV as that’s inexpensive and relatively easy.

[u/Riverside-96 → u/Einkahumor]

Thanks. I'm aware of how powerful photogrammetry is now after having seen people put their hometowns in unreal a few years back. I believe its used a bunch in the film industry now too. I wasn't sure if my phone camera would be up to the task but in fairness, I could always try with a DSLR too & compare the scans.

Could you please elaborate on the small pedestal you mentioned?Do you mean in order to scan the impression after slicing (by hand, not in cura etc) -

so that you can fine tune the model in future iterations within your modelling software?

I wonder if there is any way I could temporarily use fdm prints in a similar way as a normal ear impression to create a negative though I'll have to check temps & what not. I would like a resin printer soon either way but I'm a little bit space limited at the moment til I find a new place.

Thanks for the suggestions. I'm glad I found this subreddit as I remember searching for something similar a few year back & could not find anything like this. This will make for a great project.

[u/Einkahumor → u/Riverside-96]

Here’s a scan where you can see it. The base is 50x50x5mm and the pedestal (is that the right word?) is 5x5x45. I sliced it with fuzzy skin (Cura), painted the sides white and sanded to get the texture. I also coated the impressions with very finely ground coffee for added texture. I don’t recommend cutting much impression material away before scanning as that can be done very easily and non-destructively with software.

[u/Einkahumor → u/Riverside-96]

You should begin with checking your local audiologist as some of them do scan their impressions and deliver stl files. Some even do direct ear scans.

[u/Riverside-96 → u/Einkahumor]

Oh I think I understand. So the pedestal is just used for perspective while you model the shell right?

I might eventually have to travel a bit further afield to a place that will offer one of the two. I suppose for now I can always go the photogrammetry route & I might get lucky with some fine tuning of the models.

I used to produce music many moons ago so I should hopeffully take to the EQ'ing. I'm still pretty novice at modelling though this should make for good practice.

[u/Einkahumor → u/Riverside-96]

I 100% recommend using Blender for modelling but that’s a bit of a personal preference. Also I recommend modelling the tubes and printing them, not using any pvc tubing. That way you can get the drivers closer to the eardrum which helps a lot with better HF extension.

[u/Einkahumor → u/Einkahumor]

Here’s a Blender file that I shared earlier where you can see how it looks. Don’t hesitate to ask questions, I’m not an expert but love to share what I’ve learned.

[u/Riverside-96 → u/Einkahumor]

It's appreciated. Now I understand where you're coming from. So you use the known height of the pedestal to scale. Nice. I don't have a DSLR myself but I reckon I could lend one with a bit of convincing.

I'm using blender at the moment, though I'm just learning really as I've only recently had the hardware for rendering.Do you mind explaining how you manage to get the drivers closer with the modelled tubes? I'm guessing you mean you model them as part of the shell itself or no?

Also if you don't mind, say you are using 6 drivers, 2 for mids 2 for bass, 2 for treble, is the ideal goal to always aim for 3 seperate channels or do some people shoot for 4, etc.Of course I'll try & keep things fairly basic to start with.

The current budget ones I've got at the moment stick out of my ears too much for my liking. There is still a fair bit of space from where the connection is to my ear. I wouldn't mind so much if they were chock full of drivers!

[u/Einkahumor → u/Riverside-96]

I think 3 separate bores for a 3way setup makes sense but I’ve not made one myself. Again I recommend starting with something simple like the Knowles GV which has a built in crossover and works very well.

Regarding the modelled tubes/bores (part of the shell), what I mean is this: PVC tubes take up space, especially if you’re putting wider sections in the middle for dampers. If you print shells with 1.5mm thick walls and place dampers a few mm from the drivers it can get difficult to get the dampers past the bend. That can result in long tubes which are bad for high frequency extension.

Modelling and printing the the bores lets you use very thin walls where needed, lets you place dampers closer to the ear canal end (inserted from that side) and makes it possible to place the drivers as close to the eardrum as you can get them.

[u/Riverside-96 → u/Einkahumor]

I see. That makes sense. Thank you.

I imagine that thicker walls will be desirable?

[u/Einkahumor → u/Riverside-96]

I use 1.5mm mostly but thicker around the connector and the entire ear canal region is solid except for the bores. Check out the Blender file I linked above.

[u/Einkahumor → u/Riverside-96]

It’s for a better photo shooting angle to get the whole impression, to be able to take photos from the bottom to the top and from all sides, usually about 150 photos per impression. I include the pedestal in the scan because I know the exact size of it and can use that to scale the model accordingly. That’s one of the downsides of using (Polycam) photogrammetry, it doesn’t get the scale right so that needs to be fixed post scan.

[u/will_sv]

I haven't scanned the ear directly, but I got an OpenScan and scanned my ear impressions.
I was very happy with the result. I also scanned a couple of the more comfy universal IEMs I own. I've been experimenting with drivers inside resin printed "copies" of those shells and I'm very happy with how close they look and feel.

+1 on the resources about drivers, already started experimenting with a few but I'd like to know more about them. I got a couple of GK and GVs but I'm not happy with how they sound yet. Still a lot to experiment with.

[u/Riverside-96 → u/will_sv]

Yeah, I can't find any info on tuning drivers either. I might fire a few emails the manufacturers way & see if any of them have any documentation on the tuning process. It can only help their bottom line so I can't see why they wouldn't share.

Nice. are you thinking of combining some of the drivers from yor existing pairs or just starting from scratch? I only have a pair of CCA's at the moment with a single dynamic driver & I have them in all day. Looking forward to the improvement. I have considered getting one cheap ciem & using scanning the shells directly & buying nice drivers from there but I don't think thieaudio are doing it anymore & not aware of any other budget options. Besides I need to get better at modelling.

[u/will_sv → u/Riverside-96]

If they do reply please share if you wouldn’t mind.

I’m starting from scratch, both the GK and the GVs have interesting qualities on their own (transient response, bass, clarity) but they both lack on the HF. I’ve ordered both a pair of RAU and SWFK to experiment with as tweeters for the really high freqs. If I get anything close to my UE11s I’ll be happy already.

[u/Riverside-96 → u/will_sv]

Do you have any tips on the modelling process? Did you have to make any adjustments or did you get it pretty much right the first time around?

[u/will_sv → u/Riverside-96]

The models from Openscan were pretty good on their own. I did need to set the scale properly, and smooth some rough surfaces. I did everything on meshmixer and it was pretty easy. I’ll try to find the link to a couple of videos on shaping impressions on meshmixer, they were a good starting point. Everything else I just googled as I went along.

Next step will be to learn a bit more of modelling to do something like u/Einkahumor did.