The Art of Ear Impressions: Custom IEMs

Music has been there since time immemorial, and it has helped people create exceptional memories and enjoy their lives. Personal audio, and in particular, IEMs are an excellent way of recreating live music and can be experienced while travelling on a train, walking on promenades or even stage performances. Custom In-Ear Monitors (CIEMs) take the meaning of ‘personal audio’ to a whole new level and are used in the same scenarios. To obtain the best fit, it is essential to get a good model of the interior of your ears – referred to as an ‘ear impressions’.

Why are Custom-In Ear Monitors even used in the first place considering we already have universal (‘off-the-shelf’) In-Ear Monitors? Well, Custom IEMs offer numerous benefits include a ‘perfect-glove’ fit for your ears, a perfect seal, enhanced sound isolation and hearing music as their manufacturer intended. For these reasons, they are widely used amongst audiophiles, stage musicians, DJs and in hearing aids for those with hearing impairments. For stage musicians and singers, they have the added benefit of allowing them to hearing metronomes and backing tracks as well as personalizing the stage mix.

Why is impression-taking considered an art?

As a self-professed audiophile, striving for the best sound can be a journey in and of itself. Custom IEMs obviate the suboptimal fit in some universal in-ear models and allow a much more personalized approach to music. For this, an ear impression is needed. The best way to have your ear impression taken is by visiting your audiologist or hearing professional. Impression taking is a simple and straightforward process, but you would be wrong to presume that nothing can go haywire. A hearing care professional conducts this procedure by inserting a soft material into the patient’s ear, which then hardens in line with the ear’s shape.

The impressions made after that dictate how the final in-ear monitor will fit into your ear. It is often the reason why visiting an audiologist is highly recommended to achieve that perfect ear impression for your final custom IEM.

ear impressions

Impression-taking Techniques

The techniques used for impression taking are considered satisfactory by the majority if they reveal the ear’s structure 2mm beyond the second bend of the canal. Impression taking can be done several ways, including when the patient is chewing or when their jaws are open/ closed. Most of the earmold labs today prefer the closed jaw method. Some theories support the idea of the patient chewing before the impression material settles down in their ear. First, professionals say that when a patient chews, the material used is pushed further into the ear canal, covering more of the bony portions.

Additionally, chewing helps the soft ear tissue to move to the area where it is supposed to be. Open-jaw impression taking is mainly recommended for hearing aids remake because the audiologist gets clearer feedback from the jaws and head movements. Some earmold labs, however, recommend using both an open and a closed jaw impression. This gives the technician a broader range to assess the best type of fit. Besides the impression-taking technique, the manufacturing process is another factor that determines if the earmold will fit satisfactorily.

Image from Asius Technologies

Impression Material

Due to its ability to maintain shape, silicone is the most preferred impression material by many labs compared to the traditional liquid-and-powder material. The material’s viscosity is a significant consideration, and it is classified as either low, medium, or high. Silicone with low viscosity prevents the ear tissue from stretching. Cartridges help the silicone flow more freely into the ear canal to fill all the apertures and undercuts.

However, silicones with medium and higher viscosity prevent acoustic feedback and allow for more secure instrument fitting. Today, most hearing professionals are abandoning the use of low viscosity silicone and opting for more viscous hand-mixed one-to-one silicones.

How Audiologists Create Ear Impressions

After deciding to get customized in-ear monitors, the next step is to have the impressions taken. Ear impressions are made by licensed professionals called audiologists. With the current improvement on internet access, you can type in “audiologist near me” on the browser’s search bar to find a professional within your location. However, have you ever wondered how these experts actually take an ear impression? The following are the major steps followed by audiologists when taking ear impressions:

1.      Infection Control

Taking ear impressions is a medical procedure like any other, and infection control is a requirement. Besides infection control, the professionals ensure appropriate hygiene, regardless of the impression type they make. This is more so essential if you (the patient) present some health risk, for instance, diabetes, the risk of bleeding, or any immune system issues.

2.      Preparing the Patient

A patient’s comfort depends on how well they are informed and what to expect during the procedure. It is the audiologist’s responsibility to notify the patient of the expected sensations, explain the experience, and the time it takes for the impression to harden. Having such info will prevent the patient from becoming impatient and uncomfortable as they get a temporary hearing loss.

3.      Otoscopy

 Otoscopy refers to the close inspection of the patient’s ear before inserting the impression material. During this step, the audiologist examines both the tympanic membrane (TM) and the canal to identify abnormalities. If their qualifications allow it, they can remove foreign objects or cerumen before starting the impression-making procedure. Inflammation, infection, and drainage are cases in which the patient may need to be referred to a physician. The audiologist will only proceed with the impression-taking process only when he/she feels it is safe to do so.

4.      Otoblock

Otoblock preparation is the next step after Otoscopy. Cotton is the ideal material for Otoblock as it is more malleable. To get a deeper impression, the block needs to be flattened out to consume as little space as possible in the ear canal. With such space, the impression material fills the ear canal without leaving gaps that would otherwise result in unwanted leakage. The use of oto-ease or any other water-based product for lubrication prevents the block from adhering to the canal wall or the eardrum when conducting deep impressions. Additionally, the lubrication eases and makes the removal of the impression more comfortable for the subject.  

5.      Curing and Removal

An impression material can take between four and six minutes to cure, depending on the manufacturer. A lot of precaution should be exercised as the material cures because if it touched during that process, the ear may expand and disfigure the impression. The audiologist should let the impression cure naturally and ensure it has set completely before manipulating it. The best way to make sure the material has set completely is by gently palpating it. Next, the patient’s ear is manipulated softly as they are asked to open their jaws to break the seal. When removing the impression, pulling it straight outward may cause discomfort to the patient. Therefore, the technician is advised to rotate it towards the nose. The lubricated eardrum makes the whole process comfortable for the patient and eases the removal action. 

6.      Second Look

The ear canal needs to be re-examined after the impression is removed. During this stage, the audiologist asks the patient some questions to confirm they are okay. On the side of the impression, the technician needs to ensure no voids or imperfections were created that would result in taking another impression. The impression created should be in line with the patient’s expectations.

Process for Custom Ear Plugs ~ Perfect for Sleeping, Music, and Work
Image from Custom Earplugs

Digital Ear Impressions

Since different labs have varying skills, research shows that a scanning machine for impression taking would resolve this issue. The Digital Ear Impression also has the advantages of reduced waiting times, being more accurate and reduced postage costs. However, 3D Ear Scans are not widely accessible to all. Some audiologists and hearing centers do offer this service and so it is always good to be on the lookout. Audio brands such as Ultimate Ears are heavy advocates of the 3D scanning method and often store all their digital impressions on file which can be further fine-tuned in the future.

What is 3D Ear Scanning, and How Can It Help You? | Big Thicket
Digital Ear Impressions – Otoscan

Custom In-Ear Monitors and their benefits

Custom in-ear monitors (IEMs) are the final product when manufacturers build an IEM to fit your ear canal after receiving your ear impressions. Often, manufacturers allow consumers to customize their IEM from different choice of faceplates and shell materials. Unlike universal in-ear monitors, Custom IEMs are highly favored for their sound isolation, secure fit and comfort. This is the reason why serve a huge market including audiophiles, stage musicians, DJs and those with hearing impairments. Here, we explore their benefits more in depth:

a.       Reduced Incoming Volume

Noise from outside can be a bother, especially when you want to concentrate and get the right sound. Customized In-Ear Monitors fit in your ears perfectly and seal them off from incoming volume. With such reduced incoming volume, you will have reduced noise, hear what you need to hear, and protect your hearing so that you can enjoy what you love doing for longer.

b.      Enhanced Sound Clarity

This is courtesy of the drivers (‘micro-speakers’) installed within the monitor. It is not necessarily the number of drivers which improves sound clarity but rather the implementation of it. Most IEMs can contain a combination of the following drivers:

  • Woofer – for low-end frequencies
  • Mid-range – for middling frequencies
  • Tweeter – for very high frequencies

There has been more and more technologies implemented to combine different combinations of drivers along with innovative crossovers, materials and acoustic designs to achieve a higher sound fidelity. Both the custom and universal IEM space is a highly evolving space and it will be interesting to see where the future will take us.

c.       More Stage Space

IEMs save a lot of stage space for musicians because there is little or no use for traditional monitors. Each musician comes on stage with their equipment, and this could lead to the space being cluttered. However, when musicians use the in-ear monitors, the stage appears less crowded, and instrumentalists can move about freely.

d.      Hearing Protection

This is the most significant benefit of the in-ear monitors. These devices are manufactured and designed to create a ridge between the user and the outside. The gadgets provide sound insulation, which acts as excellent hearing protection. Manufacturers offer IEMs in different sizes so that individuals can find those which suit them best. Additionally, some of these devices are customized for maximum comfort for the user.

e.       Less Work for Sound Engineers

In-Ear Monitors allow the user to manage the sound power on the fly without the sound engineer’s intervention. The musician can adjust the monitor using its receiver in just a few seconds without requiring any help.

Sensaphonics, Inc. (@Sensaphonics) | Twitter
Prince (Singer & Musician) wearing a Custom IEM

General Cost

The rule of thumb to remember here is quality goes hand-in-hand with high prices, although not always. However, if you desire the best custom impressions without considering those you make at home, you must understand that you will be required to pay for the material and the service. Generally, an ear impression’s price and cost can range anywhere between $25 and $150. The cost depends on several factors, including:

1. The health institution you go to for the ear impression services. Different hearing aid centers and audiology clinics charge differently, but the procedure generally takes about 15 to 30 minutes.
2. The shipping fee if you decide to ship the ear impressions to the manufacturer
3. The style of the ear impression you want.

Some other aspects contributing to the total cost of ear impressions include future appointments, repairs, warranties, parts, and power source.

DIY Ear Impression Kit

Usually, you are required to visit an audiologist or a hearing care professional to get your ear impressions done at a fee. It is recommended to do it that way for maximum safety and satisfactory results. However, for informational purposes, these DIY Ear Impression Kits usually consist of the following items:

1. A syringe used to safely and securely inject the mixed material into the patient’s ears
2. Medium and large-sized otoblocks that inhibit the material from getting into contact with the eardrum
3. Bite Blocks
4.Tubs of 2-part impression material. The necessary scoops are included for appropriate usage
5. Single-use package of 2-part impression material

Besides the risk of not getting it right the first time, taking ear impressions on your own could have other detrimental risks, including the following scenarios:

1. Not well-mixed impression material adhering to your inner ear walls
2. Pushing wax build-up too deep into the ear canal, resulting in blockage
3. The impression material sliding all the way to the eardrum because the otoblock is inserted wrongly or its size is incorrect

For the first two scenarios above, you will require professional intervention to clean your ear. The third scenario is quite dangerous and could lead to a ruptured eardrum. Hence, we highly discourage anyone from using these kits due to their significant risks.

FAQs

1)   How much does it cost to get ear impressions?

Generally, the cost of getting ear impressions may be as low as $25 and as high as $150.  The process takes 15 to 30 minutes for both ears. But if you’re the DIY-type, then you can buy “an ear-impressions do-it-yourself kit”.

However, if you want quality that comes with best custom impressions, then go for a professional audiologist. You’ll pay for the service and materials, but leave there a happy customer. Other factors that may affect the cost include the shipping fee, impression style, repairs, parts, warranties, and the audiology clinic you go to for the service. Even so, some audiologists will do a free repeat ear impression if you aren’t impressed by the first one.

2)   How long do ear impressions last?

The medical grade silicone used for ear impressions may last for up to 6 months and still be usable and fitting well. However, many audiologists recommend 1 to 3 months before getting new impressions. The silicone material usually dries out, off-gas, or deforms with time, and how fast it becomes unusable depends on the storage. Luckily, many IEM companies make 3D scans of ear impressions to overcome the shortcomings of the silicone. But, since the ear canal shape changes as we age, it’s good to get new ear impressions every 18-24 months.

3)   How do you make an ear mold?

You can either get an ear mold made by an audiologist, or make some yourself. Of course the final product may differ significantly, because of levels of experience and difference in materials used. Even so, you can make some tightly fitting molds that lock tight at home. Here is what you need:

  • DIY Ear Plug Kit – Ensure you get a body/food safe silicone putty.
  • Clean ears and hands

The molding process:

  • Open the ear plug kit and take out the contents.
  • Go through the instructions carefully- It’s important to know the manufacturer’s recommended process even with this guide in hand.
  • The silicone comes in two separate putties; a silicone base and a silicone hardener. They usually have different colors, but blend to one solid color once kneaded correctly. Take out the quantity you need for the mold from the two putties and knead together using your clean fingers. The kneading heats up the material to body temperature, which makes it comfortable to the ear when you’re making the mold.
  • When the silicone fully blends to one color, we’re ready. Get something to act as a bite block to keep your mouth open throughout the remaining procedure. A mouthwash cap will be fine. Your ear canals enlarge when you open your mouth, and open-mouth molds fit the best.
  • Pull up and away the top part of the ear to allow air to escape easily while you insert the putty. Slowly and carefully insert the putty in your ear, putting slight pressure but firmly pressing. Use the excess putty to extend the mold to your outer ear. Take the excess putty off, and give it several minutes to cure-10 to 15 minutes will suffice.
  • When ready, the mold is firm to touch, with no give in when firmly pressed. Gently remove the mold from your ear by working your fingers under the edges. The twists should be slow to ensure you don’t pop your eardrums.
  • And, you just made yourself some nice ear molds. However, you need to inspect them to ensure the results are what you expected, and let them sit for several hours to fully cure and set.

4)   How long does it take to make ear molds?

Making ear molds is a straightforward process that only takes 15 to 30 minutes for both ears. But, the actual length of time it takes depends on the state of your ears and the type of silicone used. Your ears must be clean and wax-free before the molding starts. Also, different silicone types harden at different rates and will take 5 to 10 minutes to fully cure. If you go to an audio clinic that uses digital equipment, then the time needed is reduced significantly.

Final Thoughts

Custom In-Ear Monitors (CIEMs) are surprisingly lesser known considering that the ears are among the most vulnerable and sensitive parts of a human body. The main benefits of these devices include enhanced sound isolation, hearing protection, maximal comfort and potential for improved sound. However, before you get your CIEM, you will have to get your inner ear’s full structure modelled. This is what we mean by taking ear impressions, and it is done by licensed professionals known as audiologists.

There are several materials used by the audiologists for this procedure, but the best is usually open to debate. The procedure is simple, and self-impression-taking kits are available from some manufacturers. However, it is highly discouraged to conduct the procedure by yourself as there are many risks involved. Therefore, ensure you visit a qualified and reputable audiologist to have your ear impressions taken safely.  Let us know any thoughts or comments you may have…

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