DIY Exploring Fit Formulas - huge difference - TOO much difference?

Exploring Fit formulas for myself as a patient and others. Beltone Serene 17/Nexia 9

Beltone Fit me as NAL-NL2. Now, as an HCP myself, I’m learning more about the other Fit formulas, and that most Beltones are actually first fit using BAFA. Strange

I tried fitting myself using BAFA last week and the difference in experience was stark and not at all preferred. I would never have thought that a Fit Formula would make such a difference. I wonder which one is “actually” to prescription. I’m also aware that what we might “like” better, might not be what is actually addressing the hearing loss at script, and that perhaps one “should” take time to get used to unfamiliar hearing before judging the fit - maybe tolerating BAFA for a week would make me like it? It feels like I’d be suffering though - or would deviate so much from the formula that there’d be no point.

With all of that in mind, and with learning in mind, I am attaching some screen shots. Please note the difference between first time user, at 100% fit with NAL-NL2 compared to BAFA. If I’m reading these correctly, I’m currently at target in NAL-NL2, but WAY louder in NAL-NL2 than if I was fit with BAFA. Also, my Left ear would be considerably louder if I fit using BAFA and right ear considerably quieter, which would be contrary to what my brain seems to want right now - perhaps because my hearing loss in my L ear is 30+ years old, (and was left untreated until recently) and my brain adapted, and now experiences L sided gain as an offset. (just a guess) My R side hearing loss is SSNHL, two years ago, and was treated shortly thereafter

Do these differences between the fit formulas seem right to you? do they make that much of a difference?


I have been doing some reading elsewhere, and might try an in situ to allow for my actual ear acoustics in the process. That might get me closer to “reality” in my own fitting. Is that why they do in-situ? Thoughts?

Yeah so when you install Beltone Solas Max the default is usually BAFA, this is under fit, a bit lower then say NAL as you’ve noticed,not so strange as all the manufacturer’s do this,the default can be changed.

Depends, you’ve already noticed NAL plus you’ve got fit to 100% maybe as you’ve never used HA on you left use “first time” user.

Yes obviously, different formula different gains different outcomes, so it’ll take time to change.
Your left/right difference makes sense looking at you audogram, you’ll want a bit more gain on your left, although pretty easy to balance it out in Solas, yeah having a loss for 30 odd years and now trying to treat it takes time to get used to everything as for SSNHL two years ago, you say it was treated at the time, do you mean with a HA or drugs?

Good idea, most people find it follows your audiogram, not exactly but the difference could be what your looking for.
You don’t actually mention how you like these settings in you environment, as in how are you getting on with speech when you out and about.

Thanks!!! yes to both - tried steroids etc, , and now treat with hearing aids.

It’s ongoing - in noise it’s tough. My word descrim in my left ear isn’t good, and sometimes I think I’m making it more difficult bringing that up. Also, I haven’t decided if I like the MRIE mics better or the regular, but My speech, especially watching tv could be better.

Yeah it’s not easy with that loss on your left, but I will say I didn’t like the M&RIE receiver myself, I stick with the standard version.

1 Like