[TCD1975]

  I have heard recently there were acrylic housing with silicone ends available (Not 1964 ears). But I have also heard that overtime, the silicone ends will weaken and eventually detach from the acrylic shell.

 
 
Aren't Westone CIEMs an acrylic housing with silicone ends? I've never heard anyone complaining about the tips detaching from the housing with their CIEMs.

 

[goodvibes]

I'm not certain but I thought the Westone soft tips were vinyl.

 

[goodvibes]

Sounds like you have a ton of knowledge and experience which is great.

I found silicone itchy, which I guess makes me the first person you've heard say that. Why? Not sure, maybe my ears are dry and would draft that way to acrylic too...

Could be a tight fit or a sweat reaction. I suspect it's not the silicone itself. Doesn't really matter if that's your result. your ears will be a more likely to sweat with silicone. Isolation is definitely better.

 

[Blackvoodoo]

  In my experience, a high percentage of the people who state that they "prefer" acrylic have never actually experienced silicone. FWIW, I've never heard anyone call silicone "itchy" before, and I've been doing this a long time. Silicone is stable and non-reactive, and longevity is not an issue. It doesn't shrink, nor does it lose its pliability. Even the companies who promote an all-acrylic IEM line still deliver their custom earplugs in soft silicone (though usually made by outside labs).
 
We have customers still using early 2X-S models they purchased over 10 years ago. I can wear my Sensaphonics silicones 8-10 hours a day without discomfort or ear fatigue.
 
 

I have owned Sensaphonics 2X-S models for 11 years and used them right up until the second pair died after light use.   They ALWAYS made my ears itch after about an hour of wearing them (back when they worked).   My Shure Sensaphonic sleeves still make my ears itch every day.  The Shures were bought at the same time as the 2X-Ss (also 11 years old) and are still going strong despite being used for a 5 mile run every day for almost all of that 11 years. 
 
Are the 2X-S IEMs otherwise comfortable? Absolutely!  Do they sound great?  You Bet! (when they work).   The noise isolation is also killer.   As a former musician & studio engineer who is trying to protect what is left of my hearing, I aboslutely loved them.  
 
HOWEVER - and it is a BIG HOWEVER in this price point:
 
The Silicone shells make the 2X-S IEMs EXTREMELY FRAGILE.  I used them only for long-haul international airline travel at very moderate volume levels and went though 2 sets (due to driver failures) in about 5 years.  Sensaphonics repaired the first set for around $300 plus shipping etc. when a driver failed.  I still have the 2nd pair sitting in a  drawer with a dead Left HF driver that Sensaphonics refuses to repair stating they are "beyond repair".  
 
Sensaphonics blamed the first driver failure on moisture.  I kept the 2nd set of 2X-Ss in a hearing aid de-humidifier and they developed the exact same failure.   The problem is the driver connections.  They break when you press on the soft silicone to insert the IEM -simple as that.  You can actually see the strain on the connections if you just push on the side of the IEM.
 
The company does not stand by its products -and the products are prone to failure with even moderate use.  Anyone that is using a 10 year old pair of 2X-Ss probably hasn't realized one or more drivers are out.  I didn't notice it in mine for some time.  I just figured the soundstage was bad due to cabin pressure and jet engine noise.  I seriously doubt a professional musician could tell at stage volume.   
 
I wish Sensaphonics made a reliable product and stood behind it.   Id love to own another pair of 2X-Ss...they really are that good at what they do...but you know what Einstein said about insanity...   All told I sunk about $1500 in to 2X-S IEMs and got maybe 5 total years of very light-duty trouble free performance out of them.   Thats basically like buying a $300 pair of cans every year for 5 years -not a great bargain. 
 
I have a pair of AKG 240DF's that are over 25 years old and were dragged around studios like a rag-doll for over half of their life.  They still work and sound like new.    Reliability is not rocket science when its a deisgn criteria.  Neither is designed obsolescence which, I strongly believe, is Senaphonics approach to a very much niche, pro musical environment.  What does a touring band care if their $1000 IEMs have to be replaced once a year?  Its a tax deduction and costs less than a new guitar...if they even know that much about the money side of the business.
 
I've since migrated to the horrible over bloated bass of beats noise canceling junk that I got 1/2 price when Monster blew them out.   They have easilly out-lived the 2X-S track record in the  same long-haul flight duty and are the cheapest Chinese junk cans I've ever owned.  The plus side is I'm the hippest middle-aged businessman in first class...
 
Sigh...

 

[JackKontney]

Sorry to hear you've had some bad experiences, Blackvoodoo, but you're painting with a pretty broad brush.
 
Your first pair of 2X-S (and maybe your second) had permanently attached cables, which are obviously problematic in a repair situation. Today, they come with coaxial connectors (like Shure). We are constantly working to improve our designs, our construction, and our processes. Frankly, your assertion claiming "designed obsolesence," while obviously based on personal experience, is reckless, inaccurate, and insulting.
 
Sensaphonics has literally thousands of satisfied and enthusiastic customers. Personally, I've owned my 3D system since 2007 with just one issue (green cable syndrome), and bought my 2X-S in 2010 and have had zero failures.
 
Back on topic: Silicone is actually more rugged than acrylic due to its shock absorbing qualities. I have literally stepped on my Sensaphonics IEMs with no damage done - something I would not attempt with acrylics.
 
Of course - and this is my main point - your mileage may vary.

 

[Blackvoodoo]

This is pretty much the same response I've received to every inquiry I've ever made of Sensaphonics...Somehow design defects were my fault.  I MUST have abused or mistreated the product...and, how dare I criticize a company committed to...uh, making money. 
 
I was shocked by the absolutely apathetic and accusational customer service I experienced after spending what most cannot even afford on these headphones.  [size=small]I bought my 2X-Ss in 2004 and they were never ever used in a rough or hash environment.  Frankly they could not have been used more than 24 times per year since I travel no more than 2X per month.   Both of my 2X-Ss also had green cable syndrome and they developed it just sitting in the cases they were shipped to me in. [/size]
 
My Shures are at least 11 years old and have permanently connected cables not coaxial.  They are cheap E3s and they still work like new today despite enduring gallons of sweat, rain, snow, dust and having been rather harshly treated throughout their life. 
 
The connections, in conjunction with the soft silicone used in the 2X-Ss (of the vintage I own) is a very poor and fragile design that Sensaphonics has not stood behind.  Rather, they have blamed customers for improper care of their uber-fragle units.   I bought that song and dance once and even paid more money to restore my beloved 2X-Ss.  The second time I treated the 2X-Ss like a newborn baby and even stored them in a humidity free temple.  They still failed in much lighter-than-normal use. 
 
These headphones cost an absurd amount of money for the value provided.  I am not the only one who went through this issue with these headphones and I'm not the only one who was stonewalled over repeated driver failures.  I posted here on this forum in 2012 in search of an alternative and was surprised by the number of people who contacted me with similar stories. 
 
The original poster asked about Silicone vs. Acrylic.  My response is: Silicone, while generally being comfortable and providing great isolation, is fragile and is not hypoallergenic.  One of the handful of IEM companies who offers it does not stand by their very expensive product (whose cost is approximately double of its Acrylic equivalent).  Since said company's  representavie was quick to opine on the presumed hypoallergenic qualities of Silicone and the long-term reliability of their 2X-S product I felt it important to add my personal experience with the company's product.  It is also worth adding that 'itching skin and a raised, bumpy rash at the site of contact are the most common signs of an allergic reaction to silicone".
 
I have long since concluded that the reason the majority of IEM manufacturers don't offer Silicone is that is too fragile and cannot be repaired.  A minority of people are allergic to it.  I have a minor allergy to it myself and I'm still awaiting a reputable USA based company to build a high-quality, reliable IEM using silicone material.  
 
"Reckless, inaccurate and insulting" is the very description of how I was treated by Sensaphonics as a customer.   HST said: "History is hard to know because of all the hired B.S."  Well, I'm not selling anything here, nor am I in the employ of any vendor being discussed.  I don't owe anyone associated with any particular product anything.  In fact,  I work in the energy sector and have nothing to do with the headphone or music business professionally.   I am wholly unbiased in the sense that I paid for the product I'm providing an unsolicited opinion on as a user and customer.  
 
Caveat emptor. 

 

[jelt2359]

There are at least 5 IEM companies that offer Silicon right now- Sensaphonics, ACS, Customart, Noble, and Spiral Ears. Silicon hearing aids have also existed for a very long time.
 
I personally prefer the comfort and isolation of silicon. Acrylic works well too with a good fit, but it just doesn't conform to your ear the way silicon does, so I can get a more snug fit with a silicon pair than an Acrylic one.

 

[goodvibes]

1964 also offer soft canals but they do say they are less durable. I found Blackvoodo's post interesting. Not that I think it's necessarily common but when thinking about strain relief for delicate cables and connections, it would be difficult to do in a pliable yet solid medium. Cracking at the driver connections doesn't seem too far fetched in an unfortunate driver placement fit scenario. Even slight repeated bending from taking them in and out of one's ear could theoretically be an issue over time. If there's pressure when you put in your acrylics, they will be slight deformation when you put in your silicones. No idea how common this may be.

 

[Daniel4IEM]

Appreciate the healthy debate.
Anyone aware of a way to test or "sample" the material prior to getting something custom made?

Would love to be sure about my reaction prior to committing.

 

[goodvibes]

I think having a reaction is pretty rare and may not even be the silicone itself but a personal issue to the sealed, heat and sweat environment created in the canal. I wouldn't hesitate if I wanted a silicone shell and it's added isolation or just preferred a particular IEM.

 

[He Is Emil]

Oh, interesting subject . I have had really many talks and thoughts about it!

 
I think that "superior comfort of silicone" and "superior insulation of silicone" are catchphrases which are supposedly appeal to ones common sense (that could be the same common sense that will tell you that jet can't fly because big heavy metal things just fall to the ground). Actually apart from this type of arguments I can't find proper explanations on the supposed differences between comfort and seal of both silicone and acrylic CIEMs… 
 
Oh, don't get me wrong, I'm pretty sure that manufacturers using acrylic would use the same type of arguments if they have had the opportunity (and probably they sometimes do... when nobody is watching ).
 
Still most of the CIEM technology is derived straight from hearing aid industry. And these guys really do their homework when it comes to scientific investigations. Also it might be more important for them to get to the, at least statistical truth (in their volumes of production decreasing need of refits by just few % can generate pretty big $$$ savings which can be vital). 
 
So I talked to professionals a lot and searched a lot and here is some interesting read: http://www.hearingreview.com/2006/08/earmolds-and-hearing-aid-shells-a-tutorial-part-4-bte-styles-materials-and-acoustic-modifications/ .
 
 
For those who don't want to read the whole thing these are excerptions on our topic:

  Soft earmolds do not prevent acoustic feedback related to jaw movements. Consider that the increase in the ear canal volume would require the earmold to expand instantaneously when the mouth is opening and then compress just as quickly when the mouth was closing (see Figure 5). There are no soft earmolds that increase and decrease their volume in a split second. The likelihood of breaking the acoustic seal by jaw movements for both soft and hard earmolds is similar.⁵ 
 
Another study tried to determine whether clinicians fit soft or hard earmolds more successfully.¹⁰ A total of 2,731 earmolds were investigated: 1,318 of the earmolds were made from soft materials such as silicone, vinyl, and soft acrylic, while the rest were made from hard acrylic. The parameters of the molding process were monitored throughout the study to ensure consistent manufacturing. The study found that soft earmolds required 0.6% more remakes than hard earmolds. This demonstrates that there is no reason to consider soft materials superior. 
 
(…)
 
Insertion. While inserting a soft earmold, the patient may have difficulty guiding the canal portion of the earmold into the ear canal. As a result, the canal on the earmold can bend backwards, resulting in improper insertion. Hard earmolds are more suitable for these patients. 
 
Comfort. Theoretically, earmolds made from soft materials should be more comfortable than those made from hard materials. Practically, because most ears appear to be softer than most earmolds, the softness of the earmold is irrelevant. It is the ear tissue that has to conform to the earmold, not the earmold to the ear.
Results in custom hearing aid fittings confirm this opinion. The majority of shells for custom hearing instruments are manufactured from either a hard acrylic or hard ultraviolet resin. A study found that, with proper impression taking technique and competent manufacturing, less than 1% of custom in-the-ear hearing aids required a remake due to discomfort, including high gain instruments.¹¹ These results would not be so impressive if soft materials were as critical for comfort as it is commonly thought.

 
These data for me clearly says that in terms of seal and comfort (apart of comfort of inserting and removing) the material type is irrelevant to quality and technique of taking ear impression and later processing of the earmould. Other things like aesthetics and durability of finished CIEMs is another pair of shoes. 
 
Naturally statistics are statistics and there can be singular experiences and personal likings that are not to be argued with but these are personal opinions rather than common truths.

 

[JackKontney]

There's plenty of good information in this 2006 article, but it's of critical import to note that it is strictly about BTE (behind the ear) hearing aid shells, not CIEMs. Hearing aids rarely use full-concha shell structure. Rather, they are designed to be as lightweight and low profile as possible. Similarly, deep-insertion silicone molds (past the 2nd bend of the ear canal) are not considered by the author, as they are rarely used in hearing aids.

 

[jdriver]

The difference in isolation will be a non-issue if the CIEM is well fitted. Emphasis on well fitted. If it is truly well fitted you won't be able to hear anything going on around you when the music is playing even at a low volume. Mine are acrylic and I've been surprised by cars coming up right behind me while walking and I've joked that the isolation is "gun range" quality until I proved it one day when I shot a snake with a 357 pistol while wearing them. I barely heard a pop.

 

[goodvibes]

Obviously any well fitted custom will isolate well but there is a difference. A hollow acrylic shell doesn't block or damp as much energy as a solid silicone one. I use an acrylic CIEM but it doesn't bias me to the all good vs all bad type of message board arguments. In fact my old Shure se530s with a deep fit olive tip isolated about as well as these. I suspect that an er4s with deep triple flanges do as well. Obviously acrylic is good enough at isolation judging from stage use but it doesn't change the fact that silicone is a bit better. I may personally prefer acrylic for other reasons but you can't isolate better than a snug silicone shell.

 

[He Is Emil]

  There's plenty of good information in this 2006 article, but it's of critical import to note that it is strictly about BTE (behind the ear) hearing aid shells, not CIEMs. Hearing aids rarely use full-concha shell structure. Rather, they are designed to be as lightweight and low profile as possible. Similarly, deep-insertion silicone molds (past the 2nd bend of the ear canal) are not considered by the author, as they are rarely used in hearing aids.

Yes, I found it pretty interesting . But it seems that they covered wide variety of earpiece constructions there.
Yet actually I cannot see physical difference between full-concha shell and some lo-profile earpieces in terms of things we're discussing here: comfort, seal and external noise supression. Findings published in this article seem to confirm that there are none:

(...) These findings further support the supposition that acoustic seal in earmolds (and also ear-level custom hearing instruments) occurs in the ear canal. This means that the bulk of the earmold at the concha is irrelevant to the earmold’s seal. However, it should be clearly stated that the above opinion is correct only if:
•  The ear impression is properly taken;
•  Structures of the patient’s ear provide sufficient in-canal retention,
•  Mandibular movements do not break the seal, and
•  The earmold is skillfully manufactured.

 
In terms of isolation, material used (if we're comparing relatively similar in therms of weight, density and acoustic impedance like acrylic and silicone) is faaaaaar less relevant then how air-tight is the mold (i.e. how well fitted are CIEMs).
It's situation similar to sound-proof door, especially these used in recording studios or cinemas. Yes, they can be heavy but the most important factor is how well fitted they are, good are the gaskets, and whether their construction enables to push the door to the frame with big force when closing.
 

  The difference in isolation will be a non-issue if the CIEM is well fitted. Emphasis on well fitted. I

The same point from me.
 
 

  Obviously any well fitted custom will isolate well but there is a difference. A hollow acrylic shell doesn't block or damp as much energy as a solid silicone one. I use an acrylic CIEM but it doesn't bias me to the all good vs all bad type of message board arguments. In fact my old Shure se530s with a deep fit olive tip isolated about as well as these. I suspect that an er4s with deep triple flanges do as well. Obviously acrylic is good enough at isolation judging from stage use but it doesn't change the fact that silicone is a bit better. I may personally prefer acrylic for other reasons but you can't isolate better than a snug silicone shell.

I know that hollow things can seem less blocking/damping than the solid ones but this can be tricky. Let's take gypsum board walls for an example - wisely used can provide much better isolation that many solid structures. 
 
Let's also remember that after inserting CIEMs we still get some energy coming through rest of our head/body. And energy transmitted through earpieces sums with energy transmitted through other tissues. And since we change only one part of our barrier (we can't change our head ) we make changes in only one path of energy transmission. It's like changing only one window in your room to one with slightly higher or lower insulation. Since energy is summed in logarithmic scale it does not make big difference.
 
And your experience with olive tips and my experiences with triple flanges again suggests me that it is all about the seal. Not the material .