On last august I upgraded my RIC HA’s right receiver from P to UP and, as you know about UP/HP case, it was necessary to get a shell because the UP receiver must be encapsulated within its shell in one single solid piece. The shell was very big: referring to this gallery, it was the “full shell” one and it filled all the right ear’s concha (both cymba and cavum, see here).
Recently I’ve just upgraded left receiver as well from P to UP but in this case the shell is the “cShell” of the above gallery.
I’ve asked my audiologist why this big difference and he’s answered the factory decides the shells’ sizes, he just sends to it the mold of the ears.
I’m not fully convinced of his answer so I want to ask you if you experienced something like that with UP shells and, if yes, if you can tell me the reason of this difference.
Hello @audio_hunter
The reason is that they look at the audigram you’re HCP send them and the size of the mouldimpression and your wanted receivers. So then they can precisely decide what would be the best solution to hear speech with these criteria.
You’re HCP has to fill out the form and probably didn’t say that you wouldn’t agree with something else as then asked for.
Normally they ask before making if it’s alright to deliver this “not asked for’ alternative.
My main concern about this new left UP shell, much smaller than the right UP one, is the following: if my hearing loss in my left ear got as worse as it’s in my right ear, would this smaller left cshell be still good when its receiver is set at its max power? As far as I know the necessity of this particular solid shell with encapsulated UP/HP receivers is to better adsorb the higher vibrations generated by UP/HP receivers, on the other hand a UP/HP receiver put in a “normal” earmold with a hole (as for the less powerful receivers) would generate so much feedback it’d be useless. So a question (maybe dumb!) comes to my mind: can a cshell adsorb as vibrations as a full shell can? In other words: is a matter of material of the shell or of its size its capability of adsorbing UP/HP receivers’ vibrations?
I googled a bit and I’ve found this form about Unitron shell request for Blu platform HAs like mine, I guess audiologists fill it to request shells to fabric and send client’s mold with it. The strange thing is this is the only Unitron document I’ve found on these shells request and you can see there’re only “SlimTip” and “cShell” shapes to choose between, while there’d be the “full shell” option too!
@audio_hunter
That you now have two different moulds could have a reason. I surely would ask your HCP as he/ she knows why this is done as it is.
And as you found out already, yes there are many factors that can have an influence on the absorption of sound. Going from material used, form factor, receiver strength to anatomical given and unchangeable ones. Relation between hight of frequency and absorption is depending on a lot of factors, more or less experimental given. That’s why the HCP does feedback tests.
As your hearing loss can change in time so your anatomy can change in time. And no one will know/ can foresee how and what the influence will be on the total sum of loss in dB or frequency, bone conduction or air conduction. So also feedback can change over time because of these reasons.
Most important will be you have a good relation with your HCP and trust this person. And for questions like these just ask. Be open in talking about cosmetic issues as well as hearing aid issues.
Hope this helps. And try to don’t bother to much about all this complicated stuff. It is really interesting to read much about it, but it can make you pretty unsure and even afraid that bad things happen and you aren’t helped the right way…
My UP receivers use a standard skeleton type mold. I can change the receivers and wax guards by removing the receivers from the molds. What is an “encapsulated” mold mentioned?
when I say receiver is “encapsulated” within the shell, in the sense they both one are a singles solid piece, you can’t extract receiver. What’s the right word for that? @mr.smithster What are your HAs? I guess they’re neither Phonak nor Unitron.
Yep, that wording sounds correct if you cant remove the receiver.
Mine are Resound. I just didnt realize some mfg’s made them encapsulated. So if you need a new receiver do you have to buy a new mold?
If I need a new UP receiver (eg. the present stops working), yes, I have to and I think everyone who uses Phonak or Unitron HAs with UP/HP receivers shares this necessity.
I guess you don’t use UP/HP receivers, I mean the highest power RIC’s receivers Resound can supply, don’t you?
Yes, mine are 105’s, they look like this…
They are semi-soft silicone. I can easily remove the receiver to replace the wax guards or receiver which i have had to do
