Hi All,
I’ve got Oticon Spirit Synergy Spirit MiniBTE from the NHS.
I was initially fitted with open domes. I then tried double vent bass dome and finally the power dome.
I asked whether the HAs needed reprogramming as I’m aware that there is a setting in the software for this.
I was told by a couple of the fitters that programming is not required.
Does anyone have any input on this? Essentially I’ve got my HAs programmed for open domes but using a power dome at the moment.
Hi
Yes is the short answer. It is definitely preferable to have the settings changed when you change domes. The open domes have a natural sound path for low frequencies (unamplified) where as a closed dome cuts that pathway off. Generally I would expect a bass boost to be the main change if they are reset and that gives you a fuller sound.
I’m not 100% sure which is the right dome for me.
Was trying to eliminate feedback and have the domes stay put.
Think my loss suggests closed domes but they fitted me with open ones. I know the guidance suggests 40dB in the low frequencies as the level required for open domes.
Maybe I’ll try a 10mm open. Perhaps it was the 8mm that was too loose.
Thanks.
You would probably do OK with a closed fit (no occlusion) and there are advantages to having a closed fit. You can get a higher gain without feedback, plus the noise reduction works better. The hearing aid can’t reduce noise that goes straight into the ear.
If I were you, I would want closed domes with a single small vent.
You might want to think about that again. If there’s low frequency ‘leakage’ from an open dome. When you plug the leakage does the bass increase or not?
Your advice is probably the opposite of what the wearer needs, especially if they are experiencing more occlusion as a result of the closed fitting.
What you’re looking at there is the response from the aid - occluded keeps more sound in while the open fit vents more of the low frequency - it doesn’t ‘take in more sound from the outside’.
You’re confusing software compensation in the lower frequencies with venting. There’s more LF compensation routinely applied to open fits to stop the aid sounding too tinny.
This is Hearing Aid 101, did you not understand the lecture that forms the basis of your career?
What; did they just hand you different domes and send you on your way? Are these two fitters at the same location? Maybe you need to change fitters along with the domes but then, maybe I’m just used to fitters being so accomodating, they would automatically do a quick test.
Yes.
Not really possible to change fitters in this instance. It was the local NHS hospital. I have to go there to have these HAs setup.
I appreciate that they cost me nothing and hence I don’t really have the leverage of not paying…
In response to the earlier replies - the empirical evidence suggests that increasing the occlusion by switching from open to vented bass to double dones progressively increases the bass sound, despite no adjustments made to the programming.
Open domes sounded tinny to me and sticking my fingers in my ears improved the sound. Unfortunately, I found driving with my elbows somewhat difficult! 
Is it possible that, in the situation for normal hearing of the environment (not streaming)
UKNHS is talking about a hypothetical patient who has perfect low frequency hearing such that not amplification is needed in the low end, and the open fit allows the patient to hear the lows through the venting,
while Um_bongo is talking about a patient who doesn’t have perfect low frequency hearing, but maybe only slight or moderate low frequency hearing, such that a little bit of amplification in the low is still applied, and actually a little bit more than normal even by the software, to compensate for the leak due to the open fit?
Of course, in the situation of streaming, the vent doesn’t let any sound in, but instead it leaks out the streaming sound, especially the streaming low sounds.
That specific sentence there - it’s totally wrong. The software does exactly the opposite of that. The more occlusive the fittng the LESS relative gain is applied in the LF. You stick more LF gain in with greater vent size to compensate for the leakage.
Moreso it shows a lack of understanding of the Physics of the mechanism involved, which is a bit critical if you want to fit hearing aids properly.
OK, thanks for the clarification. I got it now. Yes, I agree that with more occluded dome, the software would not want to put in more low frequencies. It’d be the opposite, if any.
I used to be with “closed” domes, the tip with only a few holes in them. When my audiologist programmed my new audiogram into my aids, I got immediate feed back, so she changed me to power domes (the double dome type). That eliminated the feedback, but it does give me a bit of occlusion. My own voice sounds like it has a cold. It might be a matter of time to get used to the aids sounding differently. My audiogram is not that different from yours.
Thanks for your replies.
The audio isn’t too bad overall. I’d probably like an REM to be carried out to check things are where they should be.
I’m currently sticking with the power domes although they’re not completely comfortable.
Perhaps a mini-mould is the solution.
I’m considering IIC due to being quite active - running etc.
I run and play tennis and I wear RIC aids with IP68 rating and they handle excessive sweating just fine.
Unless you engage in a contact sport, I don’t think IIC or CIC aids would be needed.
