Help me understand cshell vs mold vs domes, please

Hearing Aids
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differences, pro’s and cons?
Is a cshell and a “custom mold” the same thing, or are these different?

I understand the idea is to trap more sound in the ear and the idea with the open domes is that I can naturally still here low freq stuff so keep it open to let that in…
I can sure tell a difference though when streaming music or speech if I stick my fingers in my ear to trap in the sound from the receivers! The sound is oh so much deeper and rich!

Interesting though if I try that in other situations (voice or other ambient sounds using the aids microphones) I can’t tell much of a difference if any at all. Is that just because my aids aren’t programmed as they would be for closed canals?

Back story and reason for the question:
I’ve been wearing my Phonak Marvel aids for a few years now, open domes.
Seems like every year or so I need to go get things “turned up” a bit for better speech understanding.

About a year ago I had her re-test, and there was a slight worsening in the very high freq end of my curve. (actually some test points improved a bit over my original test, interestingly enough to me anyway)
A couple times my Audi has hinted around at the idea of closed domes but I’ve resisted the idea. Made it clear I wasn’t excited about getting “closed off” & so far she has played along with the idea. The last go around she gave me a larger-sized open dome to try. I can’t say I could tell any difference with it…

I dislike the idea of getting closed off. There’s the comfort thing, but, I think mostly because it seems to me that I close off the low freq stuff that I can hear, then 100% of the sound I hear will be artificial. I know it’s not really 100%, but still that’s the feeling.

Now I’m back to asking folks to repeat themselves far too much so thinking of going back in. I reckon she’ll probably push closed domes. I get the idea that based on my test curve I probably just qualify for closed domes…but I’m really wondering if I should just cut to the chase and try some molds (or Cshells?)

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https://www.mid-stateslabs.com/earmolds
They this.
Explains moulds.

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Images of c-shells can be had by google image searching. Examples are seen at the bottom of the Phonak order form.

WH

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Hi Brad,

Looking at your audiogram, and my personal experience, your higher frequencies are getting to the severe level, where open domes just won’t allow the high frequency gains you need to hear the speech you’re missing.

Anyway, here’s some observations in my limited time.

Full mo(u)lds can be fully occluded, or vented, obviously this depends on hearing loss. I have some, which I drilled to increase the vent to 3mm, as the occlusion was just too much. They work ok, but my low and mid range loss is worse than yours. However, I only sense mild occlusion since I increased the vent diameter.

I’ve never tried C.Shells, but these are Custom in ear-canal shells, with the receiver fully enclosed inside. The receivers can’t be removed, so if they fail, new ones have to be made. They can be fully occluded or vented, and can have receivers that can open a vent, or close it for streaming. I never fancied them.

Slimtips are also Custom in ear shells. These can take either a receiver, or a thin tube. They can be both occluded or vented. These are my preferred choice. I have no occlusion, I get decent bass response with streaming, and zi get the high frequency gain I need. They’re also very secure in my ear, and don’t itch, like domes did.

Your other choices are:
Closed Domes: These have 2 little vent holes, and were ok, but still not allowing the high frequency gsins I need.
Power Domes: Wow, to me, these are the worst of everything. All I could hear was my own voice.

It’s all a fine balance, to get your best compromise.

Edit: Reading your conclusion, and your loss, I’d ask to try slimtips.

Peter

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I am very happy with Oticon Grip Tips. These are soft silicone and can be vented or not.

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OK, I think I’m catching on… so Cshell probably is short for “Canal Shell”
correct me if I’m off track…it seems that a CShell is simply a smaller custom mold that fits fully inside the canal, as opposed to other larger styles of molds that spill out of the canal for better sealing, or for locking into place, or whatever…

Seems that it would be a better sound seal than a closed dome. I’ve not paid close attention to anything about these in the past but I recall discussions that make it seem like the comfort and performance of these molds vs domes is personal and debatable.

so new questions. I know the Audiologist will guide me
but as a double check and for my understanding, how would the choice be made between the two (closed dome vs cshell) for me? or maybe more to the point, based on my audiogram am I anywhere near the point where I could benefit even a little bit from a mold over a dome? (benefit without trading off for too many negatives I mean?)

Also, for RIC aids, if the wire fails, can a new receiver be swapped into the molds at home or does that require either the Audiologist or sending to a lab?

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Thanks Peter, you answered a lot of my questions in my latest post while I was typing it!

Looks like slimtips are basically a non-custom cshell. Is that about right? If they are a custom mold I’m not understanding how they are different from the cshells

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I managed to get a pair of small ones, but I couldn’t get them to fit my Phonak thin tubes. They did look an upgrade to the standard closed domes though.

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@bradw
No Brad,

They are custom molds, but are hollow, whereas the c.shells fully enclose the receiver.

Peter

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It’s almost the Phonak encyclopedia about acoustic coupling…

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My computer locked up trying to access this.

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I have read all the replies and here is how I would fit. Phonak does have feedback issues at times with the high freq loss you have but I would not do closed domes as not much different than a finger in the ear with a speaker on the end. But there are some Phonak closed domes that do have a small vent. These are the ones I would try if staying with domes. My personal opinion is I would do molds (basically shells the receiver fits in that can be made with a variety of venting options). This allows for better high frequency amplification while still leaving the venting needed. Also easily modified if needed.

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thanks! and good timing too. I went ahead and made an appointment with my audiologist for next week. I plan to consider and probably even yield to her advice, but I have been leaning towards asking for a mold of some kind (although I am curious about the previously mentioned “Slimtip” as a cost saving compromise). I just generally have gotten the feeling that more folks complain about itching and such with domes…and I feel like acoustically molded shells make more sense too

If I go that way, I just pray that she gets the venting right.

I’m concerned about the occlusion and hearing my own voice
but I’m also concerned about closing off all natural sounds…because as good as the aids seem to be, they seem to be focused on recreating speech and so other sounds may or may not be replicated accurately (music, mechanical sounds, and just the world in general!)

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thought of a related question…
so that I can brace myself… what might I expect the cost to be for custom molded shells?

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Here are my latest HAs (sold P30s):

  1. Naida P30 UP with full molds and 3mm vent.
  2. Sky (Naida) M70 SP with thin tubes and slimtips*.
  3. Bolero M70 with thin tubes and vented domes.
  4. Audeo P90s with RIC and slimtips*.

*Both sets of slimtips have vents between 1.5mm & 2.0mm.

  1. I get a little occlusion with the full moulds.
  2. I get no occlusion with the slimtips in either pair.
  3. I don’t get enough high frequency gain with domes.

Slimtips v Molds
Molds may allow more gain, but mine don’t.
Slimtips don’t make your ears feel full. Like best of both worlds… the lightness and comfort of domes, but with better results.

Slimtips v C.Shells
C.Shells may offer more gain, but with your loss, I doubt you need it with careful programming.
Slimtips allow you to replace faulty receivers or tubes, so you are self sufficient.

Just for info, the Naida P30 UPs will not programme thin tubes and slimtips/C.Shells, so Molds are their only option.

Peter

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How about making earmold possible to insert very deep in ear canal to make less oclusiom?

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@bradw I would opt for the acrylic slim tip it can still be vented well and they last longer. It will also allow you to get better high frequency amplification. Hope this helps

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I asked specifically about the slimtip, but she said that just like other custom molds…that it wouldn’t be good for me, that I probably wouldn’t like it because I’d get too much occlusion effect.

I questioned about that, “even with an open vent and getting a proper deep insertion position?”

At some point I have to yield to her expertise… but I do wonder if maybe she’s just hedging bets. Doesn’t want to go to the trouble and expense…maybe a track record of too many of these things being rejected…etc…

and after the anecdotal reading I’ve done, mostly from folks here, I do still wonder if maybe the itching would be better and if maybe I’d get better coupling with something like that.

Anyway, my initial thoughts on the adjustments that were made is that it’s not quite enough. Mostly so far I’ve been in a quiet office by myself and don’t feel that I’ve given it a good enough test yet. And I’m still in the getting used to the changes phase…some sounds do sound a little “hot”, but I’ve still had to ask my daughter to repeat herself a time or two already…so I’m thinking that it could be a bit better if a freq or two were turned up another ‘notch’

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I have slimtips, and agree for all the reasons you say. Full moulds give me some occlusion, and I feel C.Shells will do the same. Domes just don’t do it for my loss.

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Your loss is similar to mine, I have zero occlusion with 1.5-2.0mm vents in slimtips.

I’d try someone else

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