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DIY IEMs (w/ hollow shells)

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In my previous 'Ible I explained how to make your own in ear monitors (IEMs). I'm not going to cover all the background information here that I did there, so if you want some more background should check that one out before proceeding. But Following the methods outlined there, the result is a solid, filled earpiece, which, if you do it right, comes out perfectly fine. However, professionally manufactured IEMs have earpieces that are hollow shells into which all of the components are installed. The advantage of hollow shells is primarily that the components are not encapsulated in plastic, which makes them easier to service or remove (though that they aren't made to be taken apart). But it's also cleaner and neater to retrofit the internal components in a premade shell then to try and make the shell around the components. Also, pouring plastic over the components leaves room for error (like plastic filling the sound outlet of the drivers, filling the acoustic tubing, filling the female connectors, etc, all of which happened to me in the process of figure things out) that can be very difficult to try and correct. Additionally, there are open port drivers (much like closed vs. open port sub-woofer cabinets) that obviously couldn't be used in the filled earpiece. There are people over at Head-Fi that have come up with ways of making hollow shells. The first method is to use a fast curing compound, fill the earmolds, dump out the excess, and then slowly keep the earmolds turning until the material sets. The second way is to start off the same, fill, dump out excess, but then to wrap up the earmolds and throw them in a clothes dryer, so that they are constantly tumbling, which keeps the material more or less evenly distributed. Either can work with the right materials and some trial an error. However, the way it's done for reals is to use UV curing (light polimerizing) acrylic, and that is what I'm going to describe here.
 
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NoForMe1 month ago
Even better news! I talked to 1964 Ears and the colloid they use (krydtaloid) is the same stuff I just for from lightning enterprises. You won't find the smaller portions on their site so call and talk to chris. Let's show him some love for breaking it down... Marozie, can you help me get the wire I need to connect the posts to the twfk driver?
marozie (author)  NoForMe1 month ago
Doesn't have to be anything special. Really small gauge magnet wire works well. Also, too me a while to find the IEM connectors, but you can get them all over the place, they're called TF10 connectors. I think I picked some up on eBay.
NoForMe1 month ago

For me the hardest part of this was locating the materials.. Good news for you,

http://www.lightningenterprises.com/ has decided to sell the hydrocolloid in smaller batches for us DIY guys.. It's around $27 Shipped for a pound. I highly recommend it because it's reusable and will make a great impression of your ear!

marozie (author)  NoForMe1 month ago
You nailed it. Most of these supplies are intended for audiologists, and therefore not sold retail. Many of the suppliers even require you to set up a professional account just ot view their catalogues. On top of that, even when you can buy supplies they're mostly in bulk which kills your cost margin and makes these projects untenable for lots of people to even attempt. Great new about that hydrocolloid - using gelatin to cast the investment can be pretty hit or miss due to the fact that it's so flexible and can easily result in a deformed shell.
pjp727 months ago
Man you've got some serious patience, I'd love to do this as I love gadgets etc. but I know that I'd lose it working with tiny part's not to mention the time it'd take I'm not the most patient person! LOL Great job though they look awesome, I've always wanted to make a wet of those ear pieces & have it so I could listen to my ipod/phone etc. bluetooth device with literally NO WIRES.
glvrrt9 months ago
Use a small dab of melted wax in the bottom of your cup to stick your impression to, this will keep it from wondering around when you poor your mold material in. It will also prevent it from getting under the bottom edge.
glvrrt9 months ago
I found, instead of trying to build the cast up later in the process, I melt bee's wax to a water consistency and give the impressions a quick dip. This does two things, 1) it gives your impression an even smooth surface over the entire piece and 2) it builds it up slightly to give you a good tight fit without being uncomfortable. It takes a little practice, but works very well.
sk8aseth1 year ago
Hey, how did you manage to get the Sonion drivers. I really want to use the 2091i as a woofer, and I've contacted Sonion, who say they only sell trays of 100, and Colsan who have not responded.
marozie (author)  sk8aseth1 year ago
Don't know what to tell you. I got them from Colsan.
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