This is approximately how a decent ear impression should look:
For an example of an inadequate ear-impression, please see discussion here:
www.head-fi.org/t/684396/new-jh-audio-flagship-siren-series-roxanne/1275#post_10056821
www.head-fi.org/t/684396/new-jh-audio-flagship-siren-series-roxanne/1290#post_10056903
www.head-fi.org/t/684396/new-jh-audio-flagship-siren-series-roxanne/1290#post_10056929
and here:
www.head-fi.org/t/578855/things-to-consider-before-getting-your-custom-iem-impressions-done-the-perfect-fit/135#post_12366845
...and examples of the impressions procedure can be found here:
(I disagree with the bite block being used in the maximum-opening position, as seen in the above video. It leads to too much tension in the jaw muscles and would only be really relevant for opera singers, or rock vocalists who scream with their mouths wide-open whilst using their CIEMs. I only use the bite block in the medium position and get good comfort and excellent seal, even when opening my mouth whilst listening to the CIEMs, but... as ever...
one should remain cognisant of the fact that ear anatomy varies surprisingly widely, from person to person, so what works for one person may not necessarily be what works best for another).
more on impressions:
www.youtube.com/watch?v=npexMDj_32g
and here:
www.rockstarears.com/earimpressions.html (the customer/patient in this video is doing it all wrong - moving around
all over the place, grinning, stooping down... really a textbook example of how
not to have ear impressions taken. It's not the audiologist's fault, just a naive customer. To get the best possible results, one needs to be as absolutely still as possible).
Keep in mind that if you have a perforated eardrum (see your doctor!) or impacted earwax, the audiologist may be unable to take impressions. Therefore, if, for example, you already know that you have issues with
earwax, you may save a wasted appointment if you make some effort to address the issue 2-3 weeks prior to your audiology appointment. You can purchase over-the-counter products for breaking down accumulations of earwax, usually in the form of ear drops (e.g. 'Otex'), or you can simply use (clean!)
*extra-virgin* olive oil, applying a couple of drops a day (using a pipette, without inserting it). If you're unsure about this, then simply see your local doctor or pharmacist.
Don't leave earwax removal 'til the last few days prior to your audiology appointment, because:
1) using pharmaceutical ear drops or olive oil takes time to work
2) in the event that your ears require syringing, this in itself may require an appointment with a several-day waiting list,
and in addition to this, syringing may leave your ear canal slightly inflamed for a few days, which could lead to inaccuracies in your ear impressions.
When you attend your audiology appointment, to have impressions taken, remember it will be easier for all concerned if you take with you some printed guidelines (both for yourself and for the audiologist) relating specifically to impression-taking for the purposes of custom IEMs:
empireears.com/ear-impressions/ (.pdf version)
jhaudio.com/files/Audiologist-Tip-Sheet.pdf
nobleaudio.com/workspace/media/uploads/support/pdfs/ear-mold-impressions-guide_1.pdf
1964ears.com/pages/audiologist
1964ears.com/img/instructions.pdf
david.rhines-customs.de/wp-content/themes/Kickass/Uploads/PDF/rcm-Abdruckanleitung-EN.pdf
This is not to insult the audiologist - the point is simply that the requirements for CIEM impressions are
not the same as the requirements for hearing-aid impressions, and far too many audiologists naively (or, in some cases,
arrogantly) assume that because they've taken a thousand hearing-aid impressions during their lustrous career, taking CIEM impressions must be exactly the same procedure.
In such circumstances, it is quite possible for an audiologist to assert that they've done CIEM impressions before, even if they never have, so although many audiologists will be honest, never simply take such assertions at face value.
In addition to the importance of the impression extending just past the 2nd-bend of the ear canal (discussed in detail, in the first 3 forum links of this post) another example of how a CIEM impression differs from a hearing-aid impression, is the importance of the full helix, including the 'crus', being moulded properly (some discussion
here) along with the tragus and antitragus.
I have found it worthwhile to calmly & politely tell the audiologist that I have very specific requirements and I would appreciate him/her briefly familiarising themselves with those requirements, so we both know where we stand, before undertaking the procedure. Please never feel too shy to do this, and never feel intimidated by the audiologist. Just be polite and open about your specific requirements,
right from the outset.
If you fail to do this, you may not get adequate impressions, and it can cost you a lot of time and money shuttling impressions back & forth to your CIEM maker, and yourself back & forth to repeat audiology appointments. It can also mean that the audiologist may feel justified in charging you twice, in the event that you need to go back for a better set of impressions.
No decent, rational, audiologist with a
normal-sized ego will object to a customer being upfront about having specific requirements - in fact, it does
them a favour, as it helps them serve you best as a customer, and satisfied customers reflect well upon their business & reputation.
I noticed the following link was also posted on Frogbeats' website:
audiologyonline.com/articles/earmolds-and-more-maximizing-patient-850
(Remember: the above instruction links are intended for Acrylic CIEMs. If you are buying Silicone CIEMs then the instructions are the same except that the vendor will probably request that you keep your mouth closed during the impressions-taking procedure). But PLEASE check with your vendor!!
SpiralEar request closed-mouth impressions for their silicone CIEMs.
VisionEars request closed-mouth impressions for their acrylic CIEMs.
CustomArt request open-mouthed impressions for their silicone CIEMs and open-mouthed impressions also for their acrylic CIEMs.
EmpireEars request open-mouthed impressions for their acrylic CIEMs.
Very rarely, an acrylic CIEM vendor may request a different method of having impressions taken. I don't know if Fitear do their impressions differently depending on whether you are a singer or an audiophile, but, apparently, they request the customer to move their jaw slightly whilst the silicone impression material is curing (
http://www.head-fi.org/t/607362/new-fitear-mh335dw-custom-iems/60#post_9089125), but (unless you purchase via a 3rd-party dealer like Jaben), they will insist on you visiting their premises and doing the impressions personally, with their own staff, so this unusual exception doesn't negate the advice in this thread, for having impressions done for almost all other acrylic CIEM vendors, via an independent audiologist.
UPDATE: As with VisionEars, I have recently heard that Hidition may ask for impressions to be done with the mouth
closed, even though they make
acrylic CIEMs. However, it may be that they make their CIEMs
slightly larger in order to achieve a very snug fit. Confusingly, I read in a
factory-tour thread that they do offer onsite customers a choice of bite-rings whilst having impressions taken, so it's not clear what Hidition really want customers to do when they're having impressions done, elsewhere.
Unique Melody apparently now like closed-mouth impressions.
Please
always check with the vendor you are ordering your CIEMs from, before you have your impressions taken.
As a side note, it is worth requesting that your audiologist use a
high-viscosity silicone, as some silicones are softer, which can make them a little less consistent for working with, when you submit them to the CIEM lab. Indeed,
EmpireEars wisely specify that they wish customers to submit high-viscosity impressions. There are many different brands of impression silicone on the market, but one example of a very good high-viscosity silicone is Dreve Otoform (tends to be flourescent green). Don't be shy with your audiologist - be confident and polite about your requirements - if they are unwilling or dismissive, then you may consider quitting the appointment and going to someone who will be more accomodating of your requirements.
It's also worth taking along a bite block of some sort, to be prepared in the event that the audiologist doesn't have any to hand (this should not be hard, as it may be uncomfortable to bite - balsa wood, polystyrene foam, a chunky pencil eraser, or similar would be OK. On my second occasion, I had to improvise by biting the side of my hand, but this is obviously less than ideal, as it increases the likelihood of jaw muscle tension, owing to the weight of one's hand, even if one tries to avoid any 'dead weight'.
Also take a handkerchief/tissue in case you find yourself drooling whilst the bite block is in your mouth.
The silicone doesn't take long to go off (approx. 4-7 minutes) and the experience is not unpleasant, so just relax and try not to laugh or smile while the audiologist is grinning at the sight of you gawping with a bite block in your gob and drool running down your chin
heheh.
More Head-fi discussion:
http://www.head-fi.org/t/470450/custom-iem-impressions-gone-wrong#post_6372502
Personally, I feel the sooner silicone ear-impressions are obsolete, and digital ear-scanning is the de facto standard for taking ear impressions, then the better it will be for everyone - in terms of accuracy and longevity of the impressions, ease & cost of supplying them to one or multiple CIEM makers (just e-mail them, instantly! - a major benefit if buying CIEMs from vendors in other parts of the world), ease of modification in computer software, to permit re-fits, etc., etc.
Although some of these benefits may currently be obtained via 3D-scanning of a supplied conventional silicone impression into digital environment for digital manipulation
www.youtube.com/watch?v=VYT7gNvLmbI
...the ideal, for maximum benefit and efficiency, is obviously to have the impressions actually taken digitally, from the outset.
I haven't heard much, in terms of industry penetration, about the digital ear-scanning methods, since their release:
www.head-fi.org/t/751094/head-fi-ces-2015-highlights#post_11229855
Also see:
http://earscanning.com
www.lantostechnologies.com
For those folks reading this thread who are new to custom IEMs, in addition to Sproketz' excellent advice, you may find the following clips on Youtube to be of interest:
www.youtube.com/watch?v=JWdwikZoXzA
www.youtube.com/watch?v=UPpHBFsvmlg
www.youtube.com/watch?v=nPKwh-xrJEk
www.youtube.com/watch?v=BbjJNfjgck0
www.youtube.com/watch?v=dGN4GaVaMY8
www.youtube.com/watch?v=OwWhku783S8
www.youtube.com/watch?v=TwupQniBWis
www.youtube.com/watch?v=SUzscWUv_9o
www.youtube.com/watch?v=MzKJKXZd1jg
www.youtube.com/watch?v=xZBoHwhyVkk
www.youtube.com/watch?v=qxUKRjgJjS0
youtu.be/BZtMSpA0lqE?t=11m39s
And here's one from 1964 Ears (thanks, average_joe & tomscy2000):
www.youtube.com/watch?v=kbKSe_e6fYQ
Thanks, Piotrus-g ('Peter', @ TheCustomArt) for this one:
www.youtube.com/watch?v=3UzpYGlxPE4
and thanks to ForceMajeure for this one:
www.youtube.com/watch?v=7C1Hhm2wCEM
Please note that although these are from UE's, Westone's, and 1964 Ears' production facilities, the same principles apply to almost anywhere
acrylic-shelled custom IEMs are made (with the slight exception that some vendors choose to inject a silicone or acrylic
FILL into the acrylic shell, once the drivers/crossover/wiring have been fitted. M-Fidelity, for example, inject silicone into their SA-43 hollow acrylic shell, and FitEar inject acrylic into their CIEMs, so the end result is a FitEar acrylic CIEM with no air inside it, just components and solid acrylic.
CIEMs made
entirely from silicone require a substantially different production process, but I've yet to see any videos detailing that. If I do, I'll update this post.
Oh, and there is currently an increasing move towards digital methods of CIEM production, so the above lab methods will eventually become obsolete (at least for the big labs).
Speaking of which, thanks to MuZo2 for this:
Fitear factory tour. Shows how digital ciem are made
www.youtube.com/watch?v=nIOjFE8U3FU
and thanks to Jude for this:
www.youtube.com/watch?v=9rP4CLxw5_0
Here's another:
www.youtube.com/watch?v=xZBoHwhyVkk
This isn't essential viewing, but for those of you with some patience, and an interest in learning where the CIEM industry may be going, this video discusses some relevant issues:
www.youtube.com/watch?v=Z8kCb0UanGY
Also, of related interest to CIEM buyers,
(although not directly related to having impressions taken):
Functional Anatomy of a BA drive unit:
www.youtube.com/watch?v=YXjCodzFI9Y
www.youtube.com/watch?v=1uzFhlpKIvM
www.youtube.com/watch?v=10noamcvsNo
For any of you feeling exceedingly brave, and wishing to try building your own CIEMs, your best bet would be to view the following thread and videos, but please understand that it is not an easy thing to configure and build a CIEM, and you are unlikely to save money doing it yourself:
www.head-fi.org/t/430688/home-made-iems/4020#post_12098298
Lastly, let's not forget what it's all aiming to achieve!:
www.youtube.com/watch?v=46aNGGNPm7s