Jul 18, 201624917 views

Massdrop 101: The Benefits of Custom In-Ear Monitors


What are CIEMs? As the name suggests, custom in-ear monitors, or CIEMs, are earphones crafted to fit one, and only one set of ears perfectly: yours.
Originally a niche product used by performing artists and sound engineers in the music industry, they've become an increasingly accessible and affordable product for the everyday music enthusiast.
Clear shells reveal the intricate design found within a Custom In-Ear Monitor

The Concept of CIEMs To explain the concept of CIEMs, let's take a quick trek into the realm of fashion. Off-the-rack suits are a common purchase for young men entering college. After finding a likeable product that's about your size, tailoring the suit is the next step; shortening the sleeve length, adjusting the waist size, and hemming the pant legs are all commonly used methods to optimize fit on a mass-produced article of clothing.
For the fashion-minded individuals seeking the best money can buy, a custom suit is the ultimate. By taking exact measurements of your body and allowing you to choose between different fits and styles cut and sewn just for you, the suit will perfectly fit all the parts of your body that are unique to you: slender or bulky shoulders, wiry or muscular arms, slender or thick thighs- a customized suit can handle it all.
Universal IEMs work in much the same way as off-the-rack suits. You can choose the right ear tips that best suit your needs or swap out cables for the right length and flexibility. Some IEMs even offer interesting tuning options in the form of a switch or parts you can add or remove. However, the shell of the product is something that can't be changed- you're stuck with the form factor that is offered.

Crafting Custom In-Ear Monitors to fit precisely into human ears is an art

How CIEMs Are Made CIEMs, on the other hand, start with getting ear impressions done at an audiologist. The impressions are then sent to the manufacturer, whose technicians work on sculpting CIEM shells from the molds you provided. When they're complete, your custom IEMs should fit perfectly into your ears, filling unique nooks and crannies for a comfortable, tight seal and allowing for comfortable sessions of audio bliss.
A mold of a CIEM prior to being filled with the drivers and wires it needs to produce sound

Why Custom IEMs? The unparalleled comfort and fantastic fit, the gorgeous design and artwork, the stories you strike up with curious individuals as you take them with you everywhere, and, of course, the sound quality, are all great reasons why you should experience custom IEMs for yourself.
The Ultimate Ears 18+ PRO CIEMs

Interview with Ultimate Ears Pro & Custom Art Want to learn more? Well, we reached out to folks in the CIEM industry to grill them on their CIEM knowledge.
Thank you very much for taking the time today to discuss Custom In-Ear Monitors (CIEMs) with our Massdrop members. Please start by introducing yourself.
Mike: Thank you for having us. We're honored to be a part of Massdrop. As way of an introduction, I'm Mike Dias, the Global Sales Director for Ultimate Ears Pro and I've been working with in-ear monitors for the last 12 years. I've made a career out of working with and interviewing sound engineers, digital pioneers, and musicians. I'm constantly trying to better understand how in-ears are used by professionals and audiophiles and I'm delighted to share some of this knowledge with your members.
Piotr: My name is Piotr (Peter) Granicki and I am the founder of Custom Art - a company specializing in silicone Custom In-Ear Monitors.

Let's start with what has to be the most frequently asked question. What advantages and disadvantages do custom IEMs have compared to their universal counterparts?
Mike: To me, this is like asking what the difference is between buying a suit at Ross versus having your own suit custom-tailored for you. It's about comfort. Fit. Feel. Style. Panache. And most importantly, it's about performance. The better an earphone fits you, the better it will sound. This has to do with how the low-end frequencies are perceived. Since most in-ears work with balanced armatures rather than dynamic coils, the frequency response is dependent upon the seal for low-end resonance. The better the seal, the fuller the sonic experience.
Piotr: The most obvious advantage is fit. Custom molded monitors, provided that the audiologist made good ear impressions, will fit like a glove and will cause no discomfort during long periods of use. Custom IEMs simply "disappear" in your ears. Good fit and comfort result as well in increased isolation, which improves the overall listening experience. The main disadvantage of universal earphones is limited space and limited tuning possibilities. But the real difference in listening experience is always very hard for me to describe. Custom IEMs create soundstage and imaging that can only be matched (but still not completely) by only the most expensive universal earphones.

Because it's a custom product, ear impressions have to be taken to mold the CIEMs. What instructions should I give an audiologist to make sure they do it correctly?
Mike: You'll want to print out and take this sheet (https://pro.ultimateears.com/media/misc/audiologist-instructions.pdf) with you. It will explain everything.
Piotr: The best advice is to check instructions with the manufacturer of the CIEM you are going to purchase. Each manufacturer has slightly different requirements and only by following those instructions will you get the best fit from your custom molded monitors. We ask our customers for impressions with open mouth stabilized with bite-block, past the second bend of ear canal. It's also necessary to include full concha in the print, as many audiologists are used to making impressions for hearing aids and those two types of impressions are typically different.

We see a lot of musical artists perform while wearing CIEMs on stage. Why do so many people use them, and what are the benefits in doing so while putting on a show?
Mike: IEMs were originally designed for stage use. Audiophiles were simply a clever bunch who realized just how good IEMs sound and figured that if they were good enough for musicians making music, then they'd certainly be good enough for listening to music. But first and foremost, they are tools of the trade. IEMs replaced traditional wedge speakers and now, musicians even use them in the recording studio and when mixing albums. The fidelity, consistency, and reliability have become industry standards.
Piotr: Custom monitors are the perfect solution for stage. Without them, musicians are exposed to high sound pressure levels during their performance and are in danger of substantial hearing loss after some time. Custom monitors also allow you to achieve a desirable mix for each individual person on stage, something you cannot do with speakers or at least not that easily.

Tell me about the materials that can be used to create the shell of the CIEM. What is considered the optimal material?
Mike: We use a nonreactive / non-allergenic acrylic that was pioneered in the hearing-aid world. And we form the shells with our proprietary 3D printing process so that it fits perfectly into your ear for maximum comfort and durability.
Piotr: In the industry, the most popular material is acrylic, which is basically plastic cured under UV light. Acrylic creates hard shells and allows for high volume production with the same shell properties, such as wall thickness or color. The second most popular material is silicone, which is much softer than acrylic, but it is harder to post-process and much more complicated for designing monitors. Both material used by professional manufacturers are bio-compatible medical grade and are designed for safe direct contact with skin.

Will the same CIEM sound different to people based on their ear shape and depth? How is the product engineered and tuned to ensure consistency?
Mike: That's a great question. Thank you for asking. We actually tune each and every earpiece based on peoples' ear shape. This is part of the handcrafted process. Not only are the earphones built to fit your own unique anatomy, they are also tuned for you. By understanding where your eardrum is and how all the different sound frequencies will interact, we adjust the internal components to always meet our golden curves.
Piotr: In theory, yes that can happen. People have different ear canals, which can alter sound waves, or they perceive sound slightly different. However, typically those differences are not extreme. We measure each unit we make using certified ear simulators to ensure that our monitors hit target frequency response. This way we know that at least in non-subjective categories, each monitor we ship is the same.

Can you explain what drivers are, and how they are used in CIEMs?
Mike: Another great question. Drivers are just another term for speakers. The speakers that we use are precision balanced armatures and these are very different than the speakers that are in your car or home. These act much more like piano strings vibrating at variable frequencies. And just like woofers and tweeters, we split the frequency range up and have different armatures focus on different parts of the spectrum. But here's the slippery slope. Many manufactures have gone down the rabbit hole of simply cramming more and more drivers into a finite space. But in truth, the driver count is irrelevant. Drivers are simply the tools that we manufactures use to sculpt the sonic nuances that we want you to hear. It's about the music - what you feel and experience - not about the number of speakers per ear.
Piotr: Drivers are speakers that are put inside the shell of custom monitors. Drivers create the sound you hear from your earpiece.

How important is the number of drivers in determining sound quality? Can a 3 driver CIEM really sound as good as an 8 or 10 driver CIEM?
Mike: Ask a painter if the number of pigments they use makes a difference. Or if you prefer a more technical answer, once you reach a certain threshold in any emergent technology, the rest is diminishing returns.
Piotr: This is a tricky question and to answer, it is both "yes and no".
Yes, the number of drivers matters because more drivers means you can create more detailed sound. More drivers also allows you to control sound better - e.g. you get separate receivers for lows, separate for mid-lows, another for mids, upper mids, highs, etc.. With say two drivers you can only control two parts of the spectrum. Typically for higher number of speakers, manufacturers use dual drivers, which are two single drivers stuck together with one sound outlet. Dual drivers have two basic advantages 1. higher SPL (they are louder than a single unit), 2. they offer lower vibration, which translates into lower distortion and thus clearer, more detailed sound.
No, it doesn't matter, because good sounding 3 or 4 drivers will always outperform poorly designed 10 driver IEMs. It all comes down to tuning and how accurate the engineer behind the monitor was able to tune each driver. Tuning monitors with a high driver count is much more difficult because it creates more potential problems such as phase or delay issues. Careful selection of drivers is also crucial here.

What is the average life expectancy of a CIEM? What can I do to increase the lifespan of mine?
Mike: We see IEM's out in the field from over 12 years ago. Our warranty is one of the best in the business and if you ever need anything after the 1 year warranty period expires, we have a flat rate repair fee. For everything. Anything you need is only $99. No questions asked.
Piotr: Typically 4-5 years. After that time it would be advised to do a refit for the sake of comfort as the ear can change slightly. Drivers should work for 10 years or more if they are taken care of. We advise our customers to store monitors in a closed case with a drying pellet (supplied with our products). For customers living in humid areas or using monitors in stage conditions, we advise getting hearing aid dryers, which use warm air to get rid of any moisture gathering inside of the monitor.
The Ultimate Ears 18+ PRO CIEMs

"The Benefits of Custom In-Ear Monitors" was written by community member Daniel Lui (https://www.massdrop.com/profile/Danny_Liu).
Woopha Kobby, Kaustav Ghosh, and 29 others

Was this Massdrop 101 article sponsored by Ultimate Ears? I ask because I only see pictures of UE products but no pictures of any Custom Art products. Where's the love for CA? Here, I'll add a picture for your viewing pleasure :)

Custom IEMs are effective, beautiful, and comfortable. But they're also about $1500. That's a lot of coin for anyone who isn't a professional musician, an obsessive audiophile, or so wealthy it doesn't matter. All that said, would I get them if I could? Hells yeah.
Let me point out the most significant benefit of custom in-ear monitors, for about a third of the population. If your ear canals aren't mostly round, you'll never get a really good seal with the silicone tips, or with sponge tips, unless you use ones that are big enough that they can expand into the oval areas. But... if they do that, then you'll have pain, because they're too big for the narrow part of your ear canal. My ear canals look like a tall rectangle, with rounded corners. Didn't know that until I got my first molds for custom earphones. The instant I saw the mold, I knew why every non-custom IEM caused pain after an hour or two. The woman who made the molds said about a third of humans have ear canals that are far enough away from reasonably round, or mildly oval, that a standard round shaped insert will cause pain. My first customs were soft silicone ear molds for Etymotic IEMs. (Note that you can buy custom tips - some of them are like tips, some are like full ear molds - for many non-custom IEMs, which gives you the fit benefit at a total price significantly less than full on CIEMS.) They were not only insanely comfortable - I could wear them for the entire flight from NYC to Singapore without pain, almost forgetting they were there - but they made the Etymotic IEMs sound AMAZING. No surprise - the better the seal, the better the sound. I have three sets of custom tips for regular IEMs (all Etys) and four sets of CIEMs. Every time I get ready to put them in my ears, I look at the insanely elongated shape of my ear canal, and remind myself why I coughed up the money for them. No pain. Great sound.
Hello are these kind of earphones good for running? can you advise?
Personally I would probably go for some wireless sports earphones instead
IMHO, for running, you should have some listening tool that lets you hear around you. If you have Etymotic earphones, they have an app for phones that will let you mix outside sound (picked up by your phone mic, or from their mic'd earphones) with your music. I run or bike with open back stuff, like Koss Porta-Pro,, because I can hear trouble.
I apologize in advance for my characteristic skepticism, but it is based in a math, engineering, and acoustics background... Conventional over-ear headphones require only a fraction of the power handling of loudspeakers, and also eliminate dispersion and room interaction concerns as well as the challenge of controlling enclosure resonances. This allows a single high quality driver to cover the entire audible frequency range, and allows a set of $500 Sennheiser HD-650's to compare to $8,000+ full-range loudspeakers. (Check out the prices of Stereophile's Class A recommended components in these two categories.) In-ear monitors take this even further, reducing power requirements due to the extreme proximity of the driver to the ear canal and further reducing bass cancellation and ambient noise effects. This should translate to further reductions in price, yet manufacturers have managed to convince buyers they need to spend a lot more to get meaningful improvements in sound quality and comfort. The most ludicrous "feature" is multiple drivers: A tiny IEM transducer should be able to operate as an near-ideal piston over the entire audio range, so why shoehorn the complexity, cost, and sonic degradation of a crossover network into the design? It is a much greater engineering feat to make a great sounding pair of loudspeakers for $1000 than it is to make great sounding IEMs for -- say -- $100. IMHO diminishing returns set in quickly above this price point.
Load 4 more comments
Nope. Not true. I've got five pairs of CIEMs that I love, they sound amazing. I've got four pairs of IEMs where I had custom silicone tips made. Only one of the single driver IEMs sounds anywhere near the quality of the multi-driver CIEMs, and that's the top end Etymotic. And they're not $100. I've got $150 Etys and they're not even close - and, I'm using the same custom fit silicone tips that Ety recommends on both, so the tips aren't the difference. That said, I've got one set of CIEMs with 10 drivers a side, one of five per side, one of three per side. The top of the line Etys, single driver, are very, very close to the three per side. They're also only about 40% less in cost (including custom tips... and the perfection of fit is a HUGE determinant of in ear sound quality) than the three driver units. Really, it's very much like my speakers. I have five listening spaces (photography studio, editing and printing work area, family room, bedroom, living room) with speakers. I've got a set of very exotic single driver speakers. I've got a couple two driver, one three driver, and one 8 driver speakers. The single driver units are not the best, even though they cost more than the two driver, and three driver speakers. Engineering skill (versus engineering theory) isn't insignificant. Besides what I talked about above, I also have three sets of CIEMs that I never use, because they suck. Live in my desk drawer. All of them were made by people who were legends in the CIEM world. They weren't cheap at all... although one of them I got at a huge kickstarter discount, the other two were sent to me for review. One one driver, one two driver, one three. Really, they're awful. Two drivers and incoherent sound. One driver and incoherent sound. Driver count doesn't define anything other than driver count. Not even coherence. My point is - I have real world experience that says your well argued theory doesn't match the real world. As a lifelong quant - meaning, I've worked in a crazy number of disciplines creating or fixing the analytics - I have a rule of thumb. Any position that posits a linear relationship, particularly based on some concept of physics, is flawed. We can talk quantum effects in molecular biology if you want... that was my last quant gig. but simpler yet... Multiple drivers, with well engineered crossovers and well engineered driver placement, will outperform the simplicity of single drivers. Speakers, IEMs, CIEMs.
Thanks for the detailed reply and for the description of your experience with IEMs. I just want to point out that I did not say that single-driver speakers are better than multi-driver speakers. My post was about headphones and IEMs. You can not make blanket statements that apply both to headphone design and to loudspeaker design. In headphones and IEMs a single driver is able to provide suitable listening levels while covering the entire audible frequency band. Real world multi driver systems are much more complex than single driver systems and as you correctly pointed out cannot be modeled as linear systems. Why would manufacturers add this complexity? I believe that in many cases this is used as marketing one-upmanship such as digital camera manufacturers used to do with megapixels. Nonetheless I'm sure there are high-end manufacturers who produce legitimate multiway designs and I'm sure these can sound wonderful. Incidentally without getting into my own academic and professional qualifications you are incorrect in implying that my post was based on theory rather than decades of real world engineering experience.
Just received my 18 +PROs. Good lord, do I love these. I don't want to use anything else. And it's not just the fit (which really isn't a 'fit'... it's the equivalent of 'built-in cabinets'; they feel like they're a permanent part of my ears), but the sound is *incredible*. I'm actually upset at myself for waiting this long to get a pair.
Getting the folks from Etymotics to provide their input would be sure to spice things up here :)
Just the info I was looking for at the right time. I'm working from an apartment on a loud street during the day and want to upgrade sound quality from bose qc 25 but of course retain as much isolation as I can. Looking at IEMs along with sealed headphones. Thanks for this.
You might also look into quality closed back headphones that fit snug over the ear. CIEM’s won’t be as comfortable for long (5-8) hrs of continuous listening due to the acrylic being hard. I have jhaudio pair and noticed a residual sensation after about 3hrs. mr speakers c-ether look good if you get an open box pair for about $999