Frequently asked questions

Below are the most common questions which are asked regarding CARL, the use of CARL, and anything else that is popular.

CARL 101

What is CARL?

CARL is your perfect patient. CARL is a manikin designed to simulate a hearing loss patient. CARL and CARL ears are made directly from CT scans creating not only a realistic anatomical model, but an ear with a realistic acoustical response. CARL is as realistic to a physical hearing loss patient as you can get.

Camera CARL includes a camera-tracking system mounted within the head to provide real-time feedback for objects being inserted into the ear canal. With this camera, you can get an inside-view to what is happening within CARL's ear canal.

How can I use CARL?

CARL can be used in any way in which you would typically interact with a patient. Even though CARL doesn't speak (yet), CARL's realistic ears represent an outlet in which you can perform otoscopy, real ear measurements (, device insertion and physical fitting, earmold impressions, cerumen management, tympanometry, electrocochleography, and much much more.

CARL can be used in training settings, research settings, and clinical settings for product demonstration to patients, all in a portable solution.

With CARL's mounting options, you can place CARL on a desktop, attach it to a desk with suction cups, or mount CARL to a computer monitor mount using a standard VESA mount on the bottom of the manikin.

What CARL options are there?

CARL has several options depending on how you believe you want to make use of your CARL.

Base CARL: Base CARLis the CARL manikin head, with one set of ears with opaque ear canals. In this option, the inside of CARL's head is empty without any additional feedback modules. This option does not have any software included, and only contains the one set of ears. Base CARL is able to be upgraded to a Camera CARL at any time with the purchase of a self-installable camera module.

Camera CARL: Camera CARL is a Base CARL with the camera module pre-installed within the head, with an included set of ears with transparent ear canals. This option includes a one-year subscription to the CARL software,

CARL Ears: There are currently three different ear anatomies available for CARL (CARL Small, CARL Large, and CARL Bendy) that are all compatible with Base CARL and Camera CARL. All anatomies are developed directly from patient scans, and represent three different clinical ear cases. All ear anatomies have clinician-verified ear canal acoustics for different cases and differing acoustic for new challenges in real-ear measurements.

CARL Carrying Case: If your CARL will be on-the-move, the CARL carrying case is a checked-bag that can fit up to three CARLs. Upon check-out or placement of the order, specify how many CARLs you would like to fit within the case.

Baby-CARL: Baby-CARL is a pediatric version of the base CARL. The pediatric head is made to simulate a two-year-old head model and includes a modular ear piece for swapping in and out different pediatric anatomies. Currently, only a six-month-old pediatric ear is available and included with the baby-CARL. The pediatric ear is produced with slightly more pliable silicone to simulate the pliable ears of a baby.

What does the CARL software allow me to do?

The CARL software allows for interaction with a Camera CARL. Using the mounted camera within CARL's head, you can utilize AHead's extensive computer-vision techniques to track any objects within CARL's ear canals while offering a real-time measurement of the object-to-eardrum in mm. This can be used to record/analyze the position of a probe-mic within the ear canal (is it within 5mm from the eardrum?), the placement of a otoblock and the expansion of earmold impressions into the canal, the placement of IICs or RICs into the ear canal, or locations of artificial cerumen within the canal. If you contact CARL's eardrum throughout any of these procedures, you will hear an audible 'OW' signifying CARL is in pain!

The CARL software also allows for testing/evaluations of procedures on CARL. With the use of user profiles in CARL, you can record the final po

What CARL is best for me?

The CARL that will best suit your use case/environment will depend on a few things:

1. Do you want to know the position of objects within CARL's canal?

If so, we recommend Camera CARL.

2. Do you want users to record the results of a procedure within a user profile which will save data and be accessibly by another user?

If so, we recommend Camera CARL.

3. Do you specialize in any pediatric care/research/training at your facility?

If so, we recommend Baby-CARL.

4. Are you limited in funding but need to offer more experiential training or more realistic research?

If so, Base CARL is still a fantastic place to start. You can always add the camera module on after the fact if you think it would provide value to your current use.

In some cases if this is used in a training environment, it may provide more value having a greater number of Base CARLs, than a fewer number of Camera CARLs. For example, if you have 10 students in a classroom at once, we recommend having a CARL for every student or every two students in a hands-on setting.

As always, our CARL specialists are available for consultation if you need any additional help. Check out our 'Needs Analysis' for a sheet to help evaluate your needs. Send this completed form to for immediate assistance.

What does the future hold for CARL?

CARL is becoming more and more like your patient every day. CARL is becoming more realistic through incremental design improvements, and will soon be able to 'hear'. CARL is moving closer and closer to your one stop shop for every audiology!

Using CARL

How long will CARL last?

CARL is made out of a high-strength plastic which will make a durable manikin head for years to come. CARL has been around for three years now, and has not seen any degradation to the head model. Given proper care of the head and properly securing it to prevent falls, CARL will last at least five years.

CARL's ears are made of a high performance, platinum cure silicone rubber material with shore hardness 10A. While these ears are extremely difficult to rip, they will degrade over time and extensive use. After in contact with many different hands, objects, and materials, the ears will gradually begin to harden and lose their flexibility. The expected life of these ears with heavy use (use at least a twice a week) is approximately two years. If the ears are only used on occasion, they should last.

The transparent-version of CARL's ears will lose their transparency over time and after extended exposure to light and objects within the ear canal. In order for maximum transparency and maximum compatibility with AHead's computer version algorithms, we recommend replacing the transparent ears once a year with continuous use.

How should I take care of CARL?

With the CARL head being made out of plastic, cleaning it with soap and water should remove any residue that may accumulate on the head. Use minimal water to avoid leakage into the CARL head (particularly with Camera CARL).

For CARLs ears, we recommend cleaning the ears with hot water and soap. The silicone is capable of high temperatures so soaking the ears in boiling water for 10min with remove most residue on the ears. The ears still have a limited shelf life and particularly in contact with other silicones (earmold impression materials may chemically-bond to the ears) they made need regular care and maintenance.

Are there any templated lesson plans to use with CARL?

The CARL Curriculum is a very important part of the CARL package. To encourage the use of CARL and the incorporation of more experiential learning and new research methodologies, AHead will supply as much curriculum and lesson plans with CARL as possible. With an early emphasis on amplification and real-ear measurement, the CARL curriculum will grow to cover all aspects of a hearing healthcare professional's duties. Stay tuned for more.

Are you interested in collaborating and developing curriculum and lesson plans for CARL? Please reach out to We are always looking to build the CARL Community and the CARL Curriculum!

Where can I get earmolds for CARL?

With CARL's consistent ear anatomies, earmolds for CARL can be pre-made without the need for making the earmold impressions yourself (although if you still want to, go for it!). Below are three options:

1. Are you interested in CARL-branded earmolds? Reach out to AHead at for your custom earmolds. This is still a pilot program so limited styles are currently available.

2. We currently have CARL's ear anatomies and several pre-made venting/earmold styles available at different earmold manufacturers. Please reach out to and we will refer to the nearest manufacturer to your location.

3. If you have a preferred earmold manufacturer which you would like to work with, you can still perform earmold impressions on CARL's ears and send in the impressions to whoever you would like. This option is preferred by customers who have their own connections with preferred vendors with preferred rates, or if you are looking for custom designs on your custom products (company logos, school colors, etc.) Alternatively, CARL is a great demo for an ear scanner to demonstrate how this new technology can be used.

What equipment is compatible with CARL?

CARL is compatible with any equipment you would use on a patient. CARL is entirely universal and made to simulate a patient no matter what equipment is being used. For these reasons, CARL is an excellent benchmark/patient/volunteer for comparing different equipment, testing out new procedures, or testing new equipment which you may not be familiar with.

CARL Software

How does the software subscription work?

The software subscription will activate from the date you first install the software. With the software subscription, you will receive all software updates for free, and will be notified upon opening the software that there is a new update available.

Once the 365 days from the activation date has passed, you will still get 100% access to your CARL software up to the last installed version number (see the latest version number here).

If you have found the last 365 days of the software subscription to be of value to you and your institution and would like to resubscribe for another year of updates, please email The cost for a software subscription renewal is $500 USD.

How do I activate CARL's software?

Upon receiving the CARL package, the software license key will be printed within the product manual. The software key is in the format of ATKXX-XXXX-XXXXX-XXXXX-XXXXX-XXXXX. Upon request, the license key can also be sent via email to the email address on file for the simulator usage and purchase.

For a step by step walkthrough of software activation, please visit our software page.

How do I know if I have the most up to date software?

Upon opening the software, a notification will appear if there is a software version update which you do not currently possess. If you would like to check this manually, you can click the 'About' button at the top right of the software window to see your license information. This pop-up will show how long your software subscription is still valid. As long as the subscription is valid, it will automatically update you if there is an update.

Finally, when you open the software, it will have a version number in the title bar at the top. This number can have be cross referenced with the software information on our software page.

Is there an iPad/tablet/smartphone app for using CARL?

At the moment, there is no iPad/tablet/smartphone version for using CARL. If this is something that you and your institution would be interested in, please email

Currently, there is only a windows application available for use of CARL.

Do I need to calibrate the camera system?

The camera system within a Camera CARL will be pre-calibrated from our warehouse. Pre-calibration includes adjusting the camera for proper focal depth, ensuring precise clarity of all transparent ear canal versions of CARL ears, and properly verifying ear canal positioning within the camera's field of view.


What are the different ways in which I can purchase a CARL?

CARL can be purchased in three ways:

(1) Online via credit card. CARL can now be purchased entirely at without speaking to a representative at AHead (don't worry - we're not offended).

(2) Direct payment link via credit card. If you've been working with an AHead representative and have been looking for a custom quote, you can pay by credit card directly through one of these quotes/invoices. If you would like any clarification or would like to speak to a representative for a custom invoice, please email

(3) Purchase order through quote. If you are working within an institution that prefers to work with purchase orders, or are looking at a larger purchase with several CARLs and will be more comfortable with a purchase order, email directly for a quote to create a purchase order.

Note: Orders shipped outside of North America must be pre-paid in advance. Contact for any questions or concerns with this policy.

Where can I buy CARL?

CARL is available for purchase directly from AHead Simulations through the online store, or through a sales representative. All orders will be shipped from Ontario Canada.

AHead does not yet have any preferred distributors of their equipment. If you are interested in carrying AHead Simulations products, or would like to work with a particular supplier for the purchase of your CARL, please email

Where can CARL be shipped to?

CARL can now be shipped worldwide. AHead's preferred carrier is FedEx international and shipping will be charged on top of the order. If you or your institution would rather use their own shipping accounts for preferred rates and further tracibility, please specify this to AHead in advance.

Note: Orders shipped outside of North America must be pre-paid in advance. Contact for any questions or concerns with this policy.

Is there any warranty for CARL?

Currently, all CARL products are included with a standard 60 day manufacturer defect warranty. If there are any issues with the product upon receival, please contact as soon as possible. AHead will stand behind its products and is currently designing an extended warranty for further security and confidence. Please contact if you have any advanced requirements for such an extended warranty program.

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