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Titanium cShell vs. Power Domes – first impressions before complaining about large venting

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Edited

I have experienced an unexpected turn of events in the last few days. My old power domes that I received with my Sphere 90 from Wholesalehearing.co.uk1 were pretty good, but have too much slit leakage to give me the proper gain above 2.5 kHz.

There is my feedback threshold with that power domes, P receiver ( v5 Pediatric):

Przed zmianą na kopułki SDS 5.0 Zrzut ekranu 2025-08-20 002211

A few days ago I bought spare Phonak power domes, which has small difference on the appearance, but the feedback threshold is better and perfect with overtuning and I can get the 100% potential of P receiver (still isn’t enough for my loss).

The silicone is noticeably harder than in previous, maybe that makes a difference:

image

The second plot twist. After 4.5 month waiting 19th Aug I received titanium cShell, which fit somewhat good, but Phonak manufacturer wanted to make me happy by force and inserted Acoustically Optimized Vent (AOV) instead of 0.6mm diameter, despite I wrote that requirement clearly in the order form. AAAAARRRGHHH!

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Of course, the feedback threshold was awfully low, poorer than in the first screen in this post.

I packed vent by tissue paper and it’s better (perfect feedback threshold), this is after new AudiogramDirect:

2nd titanium cShell P receiver vent occluded by tissue paper

As you can see, I’ve got additional (unnecessary) possibility to make more gain in frequency range below 400 Hz.

BUT there’s the THIRD plot twist!

Despite the same fitting (gains, etc.):

  1. Earplug effect (so isolation from noise) is better with harder silicone power domes than new titanium cShell with occluded vent by tissue paper!

  2. When Sphere 90 turned on, I hear sounds noticeably quieter with that cShell than with previous harder silicone power domes! So, counterintuitively, REAG would be lower with cShell compared to power domes!

I checked that also after additional AudiogramDirect after change to cShell, so I assume that phenomenon is due to Boyle’s law: the closer receiver is to eardrum the larger is . The P receiver with power dome is probably ~4mm closer to the eardrum and that possibly makes a difference in situation when I can’t get more gain from the P receiver in the Target software.

26th Aug I’ll receive another titanium cShell for older Paradise 90. I hope that will be with 0.6mm vent, so will be also narrower and I could push it deeper in the ear canal.

10 people in this conversation11 min readJump to latest
Edited

To sum up:

positive things (titanium cShell with AOV vent oclluded by tissue paper):

  1. It stays snugly in my ear because of its rough surface. I tried opening my jaw like crazy, but it still stays in place, with no change in the feedback test after that

EDIT:

(there was 2 impressions: with opened by 2.5 cm jaw technique and bite block and second impression with closed jaw and no talking).

The impressions were perfect, for the first time in my life I was temporarily completely deaf, and they were long, 5 mm after the 2nd bend of ear canal for sure. There was even a smooth surface on it, which is typical for the bony part of the ear canal, because it doesn’t have hair!.

END OF EDIT.

  1. BIG improvement - 15mm plastic removal filament. The comfort of cShell removal is infinitely increased.

  2. No occlusion effect despite my .

Negatives:

  1. Too weak earplug effect than expected, despite no slit leaks according to feedback test.
    Maybe it’s because it has too short canal stalk. I hope that with 0.6mm vent (no Acoustically Optimized Vent, as now) it will be narrower, so it could be longer.

  2. P receiver is further from eardrum, so it gives quieter sound than with power domes. Probably it’s still too weak for my high frequency gain needs.

Wow, really good feedback and perfect timing for me, as I am also considering replacing my long-time squishy double-dome soft silicone power domes with custom molded titanium. The GRIPPY look of that shell in your photo above gives me hope that it’ll stay seated.

But the SHORTIE part of it could be a deal breaker. I also need small vent hole and deeper fit in canal I’m thinking. Keep us updated!

Edited

@1Bluejay, I’ll create another topic with advices before ordering titanium, so wait a while!

@1Bluejay said:

But the SHORTIE part of it could be a deal breaker. I also need small vent hole and deeper fit in canal I’m thinking. Keep us updated!

I’ll get second titanium cShell for Paradise 90 as a spare (I hope with 0.6mm vent) in Tuesday and I’ll give a feedback! Perhaps I should order with no vent at all to make cShell canal stalk as narrow as possible!

@1Bluejay, make sure your Audi will order cShell with 3-pin receivers for your Lumities! It’s probably SDS 5.0 with UP receiver in your case - your audiologist should know, but manufactures not always (my experience)…

@Bimodal_user said:

@1Bluejay, make sure your Audi will order cShell with 3-pin receivers for your Lumities! It’s probably SDS 5.0.

OK! I have zero idea what that receiver would be. All I know is that I have the 90s - like the most powerful speaker/receiver available for the Lumity Lifes. Am I missing something?

@Bimodal_user said:

cShell with 3-pin receivers for your Lumities! It’s probably SDS 5.0.

@1Bluejay said:

OK! I have zero idea what that receiver would be.

So the three pin receivers are SDS 4 and SDS 5. SDS 5 was the redesigned receivers to accept cerustop instead of the abomination the SDS 4 take. Looking at the form for ordering the molds, titanium cshells only have cerustop available. Look at the “wax options” section of the form3. Did I get the wrong form?

WH

Edited

@WhiteHat, in Infinio (SDS 6.0) line UP receivers has HF4 as standard, which is better acoustically, which we can see even with broader frequency respense in Infinio UP receiver compared to P. Usually, UP was worse than P in frequency response.

I am not sure about that filters for UP recevers for Lumities, like SDS 5.0.

wax filters Zrzut ekranu_25-8-2025_33719_www.phonakpro.com

@WhiteHat said:

Did I get the wrong form?

I don’t know what is the proper form in USA. IIRC, in Poland is a bit different.

I feel like things go wrong so often – that is so disappointing to me that they ignored your request for a 0.6mm pressure vent. I did wonder why you were requesting such a small pressure vent, because I thought your lows looked pretty good. But now I see, it’s needed to reach optimal gain in your higher frequencies without feedback or software limiting.

I recently reached out to my audiologist and let her know I would like a 0.6mm vent placed on mine, because for one… I’ve had a 0.6mm vent since I was about 4 years old!! I am now 24 and all these new audiologists I’ve been seeing have been trying to fit me with a 1.5 - 2mm vent.

Guess what she said to me when I made my request for the smaller vent? “I am the audiologist and you are not and you need to let me do what I do.” She then went on to explain that the software determines the vent size automatically.

I didn’t have the patience or energy to explain to her that she is simply wrong. The software is calibrated to give you the largest possible vent for comfort’s sake while avoiding feedback. I need a completely different philosophy. I need the smallest possible vent for the sake of low frequency/bass preservation while avoiding occlusion (which isn’t much of a problem for me). I need musical clarity and fidelity, not comfort. I’ve been in hearing aids my whole life and I know exactly what I need and these audiologists shame me for bringing understanding and precise questions to them.

It’s hard to be personally offended when you realize how incompetent they all are, only disappointed and frustrated. I will update if/when I ever get molds with the proper venting. I returned the Sphere’s and am going to try a pair of Widex soon. I just don’t want to go back to that other audiologist again. I need to find a new one.

I don’t mean to hijack your thread by venting my frustrations. I am looking forward to your update on if the molds on the 26th have the vent sizing you requested!!

I have question for more knowledgeable.

Is it possible that, in the case of having a very tight earmold/cShell with much insertion loss in Real Ear Occluded Gain/Response, I could have a UP receiver despite my ? Assume theoretically that cost isn’t a problem.

Edited
@MDB said:

What are you hoping to gain from a UP receiver?

See screens from my Target software, especially in 6-8 kHz. Based on the course of the G50 and G65 lines, it is possible that I am underfitted over ~1,5 kHz.

@MDB said:

I think feedback is going to be your biggest limitation.

No, because of occluded (closed) fitting. I also have no problem with the occlusion effect, especially when cShell reaches the bony part of the ear canal.

It might get you a little at 6khz. Looks like high frequency gain drops off pretty steeply after that. Guess your loss isn’t well suited for . Could introduce distortion at lower frequencies.

@Bimodal_user , I’m curious why you decided to go with the 0.6 mm pressure vent vs. no vent at all?

I’m currently using power domes with my spheres (pushed in very deeply to avoid occlusion) and they form an air tight seal, so no venting at all.

Edited
@wtolkien said:

@Bimodal_user , I’m curious why you decided to go with the 0.6 mm pressure vent vs. no vent at all?

Good question. It’s because I was afraid of the possible effect of uneven pressure on both sides of the eardrum, which could dampen its vibration.

However, it’s possible that it isn’t that scary, because even with a workaround of packing the vent with tissue paper, I don’t feel that phenomenon.

So, I’ll see tomorrow the cShell for spare Paradise 90 with 0.6mm vent (I hope), and in the next few days I’ll make a decision if it would be better with no vent for as narrow and deeply placed cShell as possible, because there will be no space needed for vent canal.

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There was another topic:

Pressure vent vs. no vent earmolds - any differences?
Are there any benefits to no-vent versus pressure-vent fittings if occlusion is not a concern? I heard (maybe wrongly) that no-vent fittings reportedly have the drawback of creating a vacuum in the ear canal during insertion of the cShell, thus limiting eardrum vibration and reducing audibility. Does the no-vent option make adjusting low-frequency handles easier in, for example, Phonak Target software, i.e., more independently in relation to neighboring handles? I think also that a no-vent de…

The concern with a UP receiver would be hearing processor noise, but the sonova microphones are pretty quiet. If money is no object it’s worth a try, but it might also be valuable to have them send pictures of the build before they make it–the UP is often too big to fit well into the ear canal and so has to sit in the concha a bit awkwardly.

@monke said:

“I am the audiologist and you are not and you need to let me do what I do.”

Ugh. She can have a different opinion, but she needs to talk it through it with you. That’s patient-centred care. I’m sorry that happened.

Edited

In reply to @monke

@monke said:

The software is calibrated to give you the largest possible vent for comfort’s sake while avoiding feedback. I need a completely different philosophy.

You’re completely right! Let’s see, what vent is proposed for my :joy: :rofl: :grimacing:

image

I have also hearing loss since I was 4yo. However, I received my first - Widex Senso P8, when I was 12. I am over 10 years older than you.

I don’t have much to add except that you should consider raising your in the mid frequencies. And of course, would be extremely useful to investigate the issues you’ve described. If you don’t have access to that, I think you’ve got the right idea about everything.

@mindsil said:

I don’t have much to add except that you should consider raising your MPOs in the mid frequencies.

Do you think so? I don’t have much experience with except that it should be higher in the Speech in Noise and Music program. Fitting algorithm is 5.0 Ped with measured in AudiogramDirect (P vs. UP, both in cShell, no vent):

Output P receiver cShell no vent Zrzut ekranu 2025-08-26 011654
Output UP receiver cShell no vent Zrzut ekranu 2025-08-26 011654

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