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Can Someone Explain to me this Screenshot?

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Looking at the screenshot below (taken from the youtube video below), could someone explain to me why the area in Cyan isn’t amplified so that the wearer can hear sounds from +4k, since the HA can only hear from 70dB @4k upward?
I though the whole idea of HA is to amplify in someways sounds so they can be audible to the HA wearer, am I mistaken?

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Thank you

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Getting usable amplification about 4khz has always been difficult. The bulk of human speech is between 300 - 3300 hz. Granted, some sounds above 3300 are important but trying to match those targets can be very difficult. The feedback manager may be restricting the higher frequencies. Hearing aid usually can not match every target out in the 4-6 khz range. You get the most that can be delivered and hopefully that is sufficient.

Audible background noise can be anywhere and everywhere in the audible spectrum, unfortunately.

In reply to @Zebras

The background noise that I find most annoying is “speech babble” (other people talking) and unfortunately it’s at the same frequency as speech.

In reply to @gorgeguy

Yes. IIRC, back in the day, the telephone lines had c-message weight filters. Supposed to filter out anything outside of 300-3000 hz. One of the many reasons why music on hold was terrible. Speech emphasis was the goal.

@louyo said:

Supposed to filter out anything outside of 300-3000 hz.

My phone program on my older Aids reduce frequencies outside of this range. I did wonder why.

Others are correct that historically it was difficult for hearing aids to amplify up there, there are diminishing returns for speech up there and increasing patient complaints and feedback issues. But. . . just to be devil’s advocate, frequencies up past 4 kHz are what resolve phoneme confusion for sounds like /z/ and /p/. Pediatric targets chase them and, regularly these days, get them. Note that these are child targets rather than targets.

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You can also compare DSL 5.0 Adult targets, which are closer to NAL-NL2 but still provide a bit more high frequency audibility (compare to Baltazard’s original snap). These are rechargeable , a few years old (not current), custom tips M receivers. In this case, there’s some feedback limiting around 6/8 kHz with the current acoustic coupling.

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Compare, also, the speech intelligibility index for the pediatric targets is about 80% whereas for the adult fit it is about 60%.

And for added interest, for those of you familiar with software targets, here’s a snap of the settings that were required to meet prescriptive targets for one of the above–significantly above what the software thinks it needs.

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You’re not going to get that without . No clinician would push the highs that dramatically without being able to see what was happening in the ear. Additionally, clinicians who don’t do REM actually have no idea how far below targets hearing aid gain can (regularly) be.

Re: feedback suppression and compression to target voice. For musicians, these functions need to be turned off to allow those higher frequencies to come into play. On a dedicated program, of course.

Most hearing aids will use some combination of gain limiting and phase shifting. The latter is what gives you the awful trill in music and needs to be turned off. If the acoustic coupling to the ear and/or venting requirements are such that feedback will be a problem, gain will typically still be limited. The other options would just be. . . feedback. And that’s not going to make music sound great either. Improving the acoustic coupling will improve the high frequency response where feedback gain limiting is an issue, but there are limits with the physical coupling itself–not everyone is happy in a snug, full shell silicone earmold. :slight_smile:

In reply to @Neville

Thank you. And also you have providers that match targets, and then reset the settings to first fit afterwards. Then they can claim they have run REM and meet best practices. It’s a shame. Sometimes I’ll run their prior aids through the test box or do a transition fitting and it is very common that they are nowhere near any targets.

Oticon: Lowering of sounds with frequency composition - Speech Rescue™ BrainHearing™ technology

https://web.ics.purdue.edu/~alexan14/Publications.html6

If you want to dive into , I think this is a good start. Their fitting assistant at the top has lots of great links as well. The audiologyonline frequency lowering master class that it links is really good.

The main takeaway that I’ve seen is that frequency lowering should always be verified with probe mic measurements otherwise it is typically/likely to be more of a hindrance than helpful.

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