That’s what I heard too.
Regarding the change in FR, it can have the same effect than tip-rolling basically. So still a leap of faith eventually.
For ear canal, I even heard a custom set is basically useable for 2 years before having to be reshaped… I don’t have enough experience on the subject to check the facts.
Agreed me too…but I don’t currently have any 
+ sets that I enjoy that can now be custom fitted…it usually takes me a few tip swops (
and a bit of source and cable faffing) till I’m happy or not with a set…Maybe @JAnonymous5150 has any feedback regarding universal v’s custom when it comes to any audible differences with his collection and musician experience.
Yep. I’m very curious about custom iem, just for the sensations it can bring (and the feeling of owning something purposely made for myself only). But there’s too much potential risks tied to it for me to jump in. For approx 200 bucks all included, though, it scratches the itch, no doubt
I think HiSenior is going to start taking the 3D scans
Rather than taking the full jump to custom IEMs, would starting with custom eartips make more sense? I don’t have the link readily available but AFAIK, there’s a US company for sure that will make you sets of custom eartips (they look weird AF) that fit specific IEM models.
Yeah, it sounds safer to me.
Here we go again different tip compounds, bore gauges and internal bore profiles…
Another Rabbit hole 
Maybe so, but at least this way if you ever wanted to sell the IEM you can do it easier 
Then I guess you went down the wrong custom route?
I certainly have not, thank you very much 
Speaking of customs, at the FiR audio booth during CanJam, there was a gentleman there doing custom moldings and I thought about it… now I regret not doing it, just to have em for the future, ya know? Crap. Finding an audiologist in my area that will do moldings back in the day was kind of a pain, I remember talking to the CEO of custom art back in like, 2013? I was thinking about getting a pair of his IEMs when he first started but never went through with it.
Now Brandon’s got me thinking about custom tips…
Sorry, not sorry 
Also, I’m pretty sure if your IEM isn’t in their catalog, they’ll let you send the IEM in to make the molds so they will then have the IEM on file (respect to the hero that got custom ear tips for 7Hz Zero, fucking maniac) .
It’s like a living document for ears and audiophiles
To me (but that’s a really personal nitpick), having the tip only fitting one iem kind of defeats the purpose of having a tip.
But I can definitely see some people doing this as a compromise.
I actually thought about doing this for a few of my special IEMs, like the Monarch’s or Dark Magicians. The ones I know I’ll most likely never sell. But I get what you’re saying, @Erokh
I have thought along these lines before; I think about getting some customs for a set I really like, but then I remember how often I swap tips even across units and change my mind. I also enjoy tip rolling a bit, sometimes I prefer a lil’ tilt in one direction or another (or find that I get less fatigue in a long session by changing the shape and fit in my ears).
I would only think about custom tips once I’ve found my actual endgame sets where I’m like “I’m actually going to get out of the hobby” and I know that’s a set that’s going to be in it for the long haul. Mostly because I don’t see myself buying a TOTL set that comes in a custom option anyway.
Anything short of that though, I’ll just use my box of ear tips…that probably is the price of a custom job anyway. But I digress…
I’ll give you my experience and advice regarding CIEMs vs UIEMs, no problem. As far as sound changed from universal to custom goes that really depends on the individual IEM. There are some general changes that tend to apply across the board though. So, in general, CIEMs will fit more comfortably, isloate better, seal better, and cause fewer problems with fatigue/pain from wearing them over long sessions. This is all assuming they’re well made from proper scans. Problems regarding poorly done scans and poorly made CIEMs are much rarer than they used to be because of the increase in the accuracy of ear scan technology and the better tech used to make CIEMs these days.
Now, with individual models you can get some pretty significant changes from the universal versions though many manufacturers do their best to measure the IEMs and compensate as needed so that the universal and custom versions are as close to identical as possible. It’s common for the CIEM version to pick up a bit of bass extension and punch (likely from deeper/better fit and better seal) and low level detail and microdynamics often become clearer and easier to hear most likely for the same reason(s). When going to CIEMs from a UIEM when a bone conduction driver is involved the changes can be much more noticeable and significant depending on how the BC driver is implemented because it is brought into much closer proximity/contact with the inner ear and thus is able to function more effectively. I have found that DD or Hybrid CIEMs tend to exhibit lesser differences than their all BA counterparts. I have also found that the closer fit on CIEMs can sometimes change how closely bass ports/holes are to the ear which can also have significant effects, increasing bass quanitity. Last, but not least, IEM designs that employ tuning tubes that go directly from the nozzle to the driver(s) also tend to be effected less by changing to a custom fit than IEMs that are designed with acoustic chambers or open inner shell topologies (for example coaxial designs, BAs in the nozzle w/ DDs secured the the shell behind, etc).
I think that covers my observations that apply generally as best I can so now we come to advice. This may seem obvious, but I wouldn’t go with a CIEM over a UIEM if you have any desire to resell and are wanting to recoup funds. Reselling CIEMs is hard and they only fetch a fraction of the MSRP because the buyer has to go through the trouble and expense of having them reshelled to fit. So basically, I would stick to UIEMs unless you’re purchasing a pair that you know you will like and be keeping long term or if recouping the money in resale is not important to you and you’re fine with taking a big loss or possibly not being able to resell at all. Also important to note, CIEMs actually require a bit more maintenance as far as cleaning goes than UIEMs. I clean all my IEMs regualrly regardless, but CIEMs really need to be cleaned after pretty much an extended use and stored in a dry area and/or with descant packs. This needs to be done preventatively because it’s much harder to try to get gunk and blockages out of your CIEM after it has built up than it is with your average universal and it’s often not cheap to have to pay the manufacturer to crack it open for cleaning and repair if something goes wrong because you didn’t take proper care of your CIEMs. Lastly, if you have a pair of CIEMs that you’re keeping for a period of years, be aware that your ears and, most importantly, your ear canals change shape over time so you may eventually need to have the CIEM reshelled. For example, I have had my 64Audio A18s for a little over three years and I was still totally comfortable with them, but when I got new scans done for a pair of A12t I was having made, my audiologist happened to mention that there was a noticeable change in the inner angle of my right ear canal (I have jaw problems from an old injury so mine probably change faster than average, but everyone’s change according to my doc). After hearing that I decided to have the A18s reshelled using my new scans even though I hadn’t noticed an trouble with them just to see how big the difference was. When I got them back and popped them in, I did notice a deeper fit, slightly better isolation, and that it was easier to get the IEM seated. I never noticed any issues due to the slow changes over the course of years and likely wouldn’t have for even longer, but my point in bringing it up is that eventually CIEMs will need to change with you so it’s something to think about though most companies I have worked with will reshell their own CIEMs at very reasonable prices, often way less than their everyday CIEM reshelling fee they charge.
Anyways, if you, @Ohmboy , or anyone else have any specific questions, about something I didn’t cover feel free to ask and I’ll do my best to answer. I hope this was helpful! 
P.S. Sorry for any typos. Typed this on my phone while riding in a moving vehicle with my big caveman thumbs. 
Edit: Finally fixed what seemed like a million typos so that any future readers might actually think they’re reading useful experiences/advice rather than the musings of an illiterate child.
THAT is a long complete and satisfying first hand answer. Thank you very much, sir 
I aim to please. Sorry for the wall of text. I just wanted to make sure I was sharing everything I would’ve wanted to know when I was looking into CIEMs for the first time.
BTW, I had a few sets of the EarTune Fidelity custom tips made from the same scans for some of my UIEMs in my collection so I can see how they perform compared to full on CIEMs. They’re waiting for me at home for my next break. I’m definitely interested to see how they stack up. I’m kind hoping it’ll be a best of both worlds scenario where I’ll get most of the benefits of CIEM fits while still having UIEM usability and resale options. We’ll see. I will definitely be posting something on HFG after I get some time with them.
