Home-Made IEMs
Oct 22, 2021 at 7:57 AM Post #13,457 of 13,531

kkugel

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Are you importing your impressions before or after the digital trimming process (via meshmixer f.e)?

I assume once trimmed and smoothed, the tight bends and creases should not be there so it would be less of a problem.
You can also use Instant Meshes (this is can be downloaded from github: https://github.com/wjakob/instant-meshes ) to transform the obj to quads before importing to fusion360.

Speaking of which if anyone is interested, there is a rather nice android/ios app for sculpting digitally I can recommend called Nomad Sculpt. Meshmixer is really the best and simplest tool for trimming but the sculpting brushes are lacking (no easy masking option as well as some brushes intensity, behavior and control is not that great). One could export midway processing from Meshmixer to Nomad sculpt to do some arrangements with brushes and import back in Meshmixer for final smoothing, thickening, hollowing etc...

Nomad sculpt learning curve is much lower than Zbrush or Blender and does the job. The brushes are good and using low values allow for small work to be done nicely. The 2 main brushes I recommend are flattening and smoothing. Flattening mainly used as a scrapping tool ( a bit like you would Dremel regular impressions). Flattening in meshmixer is rather bad and I never found a a good balance with it. There is a nice Scrape brush in Blender that is quite nice but Blender's learning curve is annoying...
Thanks so much for the thorough advice! I used Blender to convert to quads now. This kinda destroys the sharpness of cuts, but I just plane cut them again in Fusion now
 
Oct 22, 2021 at 11:35 AM Post #13,458 of 13,531

ForceMajeure

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Thanks so much for the thorough advice! I used Blender to convert to quads now. This kinda destroys the sharpness of cuts, but I just plane cut them again in Fusion now
I really don't recommend doing the trimming part in Fusion...I have no idea about the smoothing that way and what features of the ear it can crush along the way.

It's also usually computationally intensive, especially when importing raw scanned files (even more if not smoothed already) and converting quad to tspline>correcting errors>tspline to brep...It can crash easily depending on the quad counts.

The trimming, thickening and hollowing should be done with another software such as meshmixer. It's much easier then to import and play with.


You can easily close holes and repair the file with meshmixer using the inspector tool in the analysis section. Much easier than repairing while doing the quad to brep to tspline conversion in fusion. It will repair the bulk of errors and will leave you with potentially a small error count once imported in fusion, that will be easier to repair before the final tspline to brep conversion.

Once you are done with the the trimming and created the shells (that you could normally print at this stage), you could easily then convert to quads using Instant Meshes (you can control the number of quads and shapes with Instant Meshes to keep the features of your impressions as well).

Here is an example of an ear impressions that has been worked on via MM and another software for brushes as well as thickened and imported in Instant Meshes
1634915665710.png

I can then use the target vertex count to allow for more resolution for the quad count with higher subdivisions.
Here I have bumped up the vertex count and solved. Once extracting the mesh I use pure quad meshes and you can see the result
1634915816268.png


Here you can see the import in fusion
1634915997512.png


after a small repair job inside fusion that is the tspline result
1634916236701.png

1634916306012.png


The bulk of the work is actually trimming the raw impression in MM and other software to get a clean result.
It requires experience trimming in the physical realm especially if you want clean looking fp shapes and allow for enough space inside

I really don't recommend doing any kind of trimming inside fusion.
 
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Oct 22, 2021 at 12:04 PM Post #13,459 of 13,531

JEHL

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I'd like to think that bone conduction works on the same principle as traditional hearing in that vibrations get turned into electrical signals that are fed to the brain to get processed into what we recognise as sound. The big differences being that:

1. The eardrum is not used much if at all. Instead the cranium does the job of transfering vibrations. Presumably this means not just each head may have a unique response to the frequency range, but different parts of the head may have different responses as well. Although since what I'd like to try is a DD+BC hybrid I assume this means the concha bowl is the part that will transfer the vibrations.

2. There's no air in between since this actuator want to rest as directly into the cranium as possible to achieve bone conduction... This presumably means measurement microphones won't do us any good here.

Am I just hopeless in the end?
 
Oct 22, 2021 at 2:23 PM Post #13,460 of 13,531

ForceMajeure

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Bone conduction is a subject that is actually still undergoing some development in the hearing aid world. Usually it used when there is an issue with the middle ear (where small bones that transfer and amplify the mechanical energy from the tympanic membrane to the inner ear) not being able to transfer air conduction but the inner ear still works.

I have seen a few reviewers trying to measure the bone conduction effect on a frequency response with a regular mic. Unfortunately this is not the way to do it ...(although those bc application indeed had a very minimal impact on the actual sound but that's not the point).

You need an artificial mastoid to measure the vibration and convert it into an actual forced transferred that mimics the human skin and bone structure (there are solutions from B&K)... you can then convert the output to an actual dbspl graph. ofc it's like the iec711. it is a approximation of the avg human skin and bone but everyone is different.

The first issue you face is of course mechanical impedance mismatch when using a bc device inside a shell and not directly against the bone structure. This will vary depending the contact area, where it lands with each individual etc...so you'll have a hard time evaluate it's effectivity.

It will vary between folks depending on how the shell rests against their skin and bone. Basically it's like not having a good seal with a tip...So the effect one would experience will be vastly different from the effect another one would depending on anthropomorphic features and matching with the shell. And that's assuming you've taken into account the optimal scenario.
 
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Oct 22, 2021 at 2:48 PM Post #13,461 of 13,531

Wgibson

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You talking sonion bone conduction, or the big 1" (25mm) type? You could glue a big one on top of an iem faceplate and wire it up, see what happens.
 
Oct 22, 2021 at 5:09 PM Post #13,462 of 13,531

kkugel

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I really don't recommend doing the trimming part in Fusion...I have no idea about the smoothing that way and what features of the ear it can crush along the way.

It's also usually computationally intensive, especially when importing raw scanned files (even more if not smoothed already) and converting quad to tspline>correcting errors>tspline to brep...It can crash easily depending on the quad counts.

The trimming, thickening and hollowing should be done with another software such as meshmixer. It's much easier then to import and play with.


You can easily close holes and repair the file with meshmixer using the inspector tool in the analysis section. Much easier than repairing while doing the quad to brep to tspline conversion in fusion. It will repair the bulk of errors and will leave you with potentially a small error count once imported in fusion, that will be easier to repair before the final tspline to brep conversion.

Once you are done with the the trimming and created the shells (that you could normally print at this stage), you could easily then convert to quads using Instant Meshes (you can control the number of quads and shapes with Instant Meshes to keep the features of your impressions as well).

Here is an example of an ear impressions that has been worked on via MM and another software for brushes as well as thickened and imported in Instant Meshes
1634915665710.png
I can then use the target vertex count to allow for more resolution for the quad count with higher subdivisions.
Here I have bumped up the vertex count and solved. Once extracting the mesh I use pure quad meshes and you can see the result
1634915816268.png

Here you can see the import in fusion
1634915997512.png

after a small repair job inside fusion that is the tspline result
1634916236701.png
1634916306012.png

The bulk of the work is actually trimming the raw impression in MM and other software to get a clean result.
It requires experience trimming in the physical realm especially if you want clean looking fp shapes and allow for enough space inside

I really don't recommend doing any kind of trimming inside fusion.
Wow nice, thx! I do trim in MM, i just do the last faceplate side cut in Fusion, so I can use less quads and still get sharp edges.
 
Oct 22, 2021 at 5:12 PM Post #13,463 of 13,531

kkugel

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I really don't recommend doing the trimming part in Fusion...I have no idea about the smoothing that way and what features of the ear it can crush along the way.

It's also usually computationally intensive, especially when importing raw scanned files (even more if not smoothed already) and converting quad to tspline>correcting errors>tspline to brep...It can crash easily depending on the quad counts.

The trimming, thickening and hollowing should be done with another software such as meshmixer. It's much easier then to import and play with.


You can easily close holes and repair the file with meshmixer using the inspector tool in the analysis section. Much easier than repairing while doing the quad to brep to tspline conversion in fusion. It will repair the bulk of errors and will leave you with potentially a small error count once imported in fusion, that will be easier to repair before the final tspline to brep conversion.

Once you are done with the the trimming and created the shells (that you could normally print at this stage), you could easily then convert to quads using Instant Meshes (you can control the number of quads and shapes with Instant Meshes to keep the features of your impressions as well).

Here is an example of an ear impressions that has been worked on via MM and another software for brushes as well as thickened and imported in Instant Meshes
1634915665710.png
I can then use the target vertex count to allow for more resolution for the quad count with higher subdivisions.
Here I have bumped up the vertex count and solved. Once extracting the mesh I use pure quad meshes and you can see the result
1634915816268.png

Here you can see the import in fusion
1634915997512.png

after a small repair job inside fusion that is the tspline result
1634916236701.png
1634916306012.png

The bulk of the work is actually trimming the raw impression in MM and other software to get a clean result.
It requires experience trimming in the physical realm especially if you want clean looking fp shapes and allow for enough space inside

I really don't recommend doing any kind of trimming inside fusion.
I wonder how you make the cuts so clean as to get a clean FP shape, do you have any advice on that? :D
 
Oct 23, 2021 at 8:53 AM Post #13,464 of 13,531

ForceMajeure

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I wonder how you make the cuts so clean as to get a clean FP shape, do you have any advice on that? :D
I am not sure exactly what you mean here, but if you mean the perimeter around to get the shape, then I just remove the bulk of impression material with raw cuts (and make solid) like I would do with a physical impression.

Then scrap around bits by bits with brushes like I would do with a rotatory tool. To match shapes for both sides I usually end up facing both impressions on top of each others (fp against fp, positioning is slightly complicated) to slowly scrap the material around the other one after I shape the perimeter of first one.

The first thing one should do when importing both raw impressions in MM is to position them side by side so they are more or less even and features on them are more or less at the same height (ears are not exactly symmetrical so experience come into play here). This is crucial to do before doing any cuts. Doing so will remove most guesses while trimming later on.
 
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Oct 24, 2021 at 5:55 AM Post #13,465 of 13,531

swtnate

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soooo, real talk. I've made a couple headsets lately that will not sit snugly in the 711 coupler. What do you use in its place? I've look all over Ali and nothing. I have the Sonion attachment and the knowles one and the earphone one. Any guidance?
 
Oct 25, 2021 at 4:15 PM Post #13,467 of 13,531

ForceMajeure

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Can anyone recommend an handheld uv curing light (dentists ones) that works for egger/dreve and lacquer etc...

The last one I had that was working great just gave up and I have just received a new one. but unfortunately this time around the UV led they use doesn't cure (since it doesn't cover the lower uv spectrum range). I suspect they started using cheaper UV led that are blinding blue but barely cure the proper range.
 
Oct 25, 2021 at 7:29 PM Post #13,468 of 13,531

Lamim Rashid

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Had a few quick questions related to BA choice.

So I know of a manufacturers switching from sonion 38 + sonion 33 series ba drivers to sonion 38 + Knowles 31 series ba drivers for low/low-mid frequencies. They are keeping the rest of the high frequency range to 8 bellsing twfk ba drivers. So the only real change is the move from sonion 33 ba to Knowles 31 ba. What's the difference here, which one is actually better?

My next question is a separate question. I want to know which of the following configurations would cost more (a rough guesstimate since I don't know all the exact drivers used), assuming they use the same DD.
Configuration A:
2*Knowles RAD-33518 for high frequency 4*Sonion 2600 for mid frequency
1*10.2mm DD for bass
Configuration B:
2*Knowles twfk for ultra high frequency
2*sonion 2389 for mid-high frequency
2*sonion 37 series for mid-low frequency
1*10.2mm DD for bass

And a last bonus question since this one is the most subjective and depends on too many other variables, which of those two configurations do you guys think is best?
 
Oct 25, 2021 at 8:48 PM Post #13,469 of 13,531

mattmatt

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Can anyone recommend an handheld uv curing light (dentists ones) that works for egger/dreve and lacquer etc...

The last one I had that was working great just gave up and I have just received a new one. but unfortunately this time around the UV led they use doesn't cure (since it doesn't cover the lower uv spectrum range). I suspect they started using cheaper UV led that are blinding blue but barely cure the proper range.
https://a.aliexpress.com/_mLJuPEe
Really really powerful.
 
Oct 25, 2021 at 9:11 PM Post #13,470 of 13,531

ForceMajeure

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This looks crazy powerful.
What UV range did you get for this one (365nm)?

I know some slightly higher ranges can also penetrate darker colors and still manage to cure various types of resins and glues because the UV bleed covers more than a certain exact region on the spectrum (albeit with slightly less peak power but still good enough to cure).

I wish I could find the same dentist handheld UV I had again and be sure they didn't skimp on the led inside without buying all of them. The fact that it was with a battery was nice and didn't get in the way. On the other hand it was its culprit as well before the led burned completely.
 

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