A question regarding frequency lowering candidacy

Audioscan Verifit can be used to objectively determine frequency lowering candidacy and properly adjust frequency lowering settings to restore audibility for important speech cues with minimal interference with the existing aided bandwidth. The frequency lowering clinical procedure begins first by completing a conventional Speechmap verification fitting. Once the fitting is completed, you get Real Ear Aided Response result obtained in the presence of a 65 dB SPL average speech passage (ISTS signal).

Next, if you’re going to activate frequency lowering, then you must first identify the maximum audible output frequency (MAOF) range. The MAOF range is the range of frequencies that can be identified using as your starting point the previously measured 65 dB SPL REAR average speech banana.

Since I don’t have an Audioscan Verifit I tried to simulate the output. In this photoshoped image, that include my left ear audiogram, the low-frequency end of the MAOF range is defined as the frequency where the aided long term average speech spectrum (LTASS) for an average speech input (the thick line in the middle of the green shaded area) first crosses back under threshold. The high frequency end of the MAOF range is defined as the frequency where the top line of the green shaded area for an average speech input first crosses back under threshold. The range of frequencies between these two points is the MAOF range.

According to this simulation that is not precise for sure, the low-frequency end of MAOF is at 500 Hz and the high-frequency end is at 1300 Hz. Only two or three frequency lowering systems can lower the high frequencies below 1300 Hz - The Enhanced Audibility Extender by WIdex (lowers down to 650 Hz), Sound Recover 2 by Phonak (down to 800 Hz) and maybe Spectral iQ by Starkey (500 Hz). All high frequency sounds should be lowered and positioned so that the upper shoulder of the lowered hump lands inside of the MAOF range. Ideally, the downward side or upper shoulder of the lowered hump should be positioned as close to the high frequency end of the MAOF range as possible.

What do you guys think about my experiment? Can I get any benefit with frequency lowering or the situation is hopeless with such a severe loss?

This is the simulation with my right ear audiogram. With only 920 Hz high frequency end of MAOF I guess only residual energy of the lowered sounds will be aidable.

The Audioscan instructions concerning how to set up frequency lowering uses the S as the dropping point for high cut off, I think that’s what I read.

I use Phonaks Sound Recover 2 aggressively using the S SHH sound as the limit for high cut off. Your hearing loss is worse than mine so I really don’t know if this frequency lowering technology will get low enough for you. Something else that I used for a gauge was hearing alarms, birds, kitchen appliances and the blinker in the car. These were all new sounds I have not heard in years. At that time speech was still very garbled and unclear. It took 3-4 months for speech to start getting better. Along with this speech came music I actually enjoy music again.
At this time I am using Phonaks Audeo M90 RT aids with power receivers and soft silicone molds.

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I wonder how high the average speech spectrum LTASS (the green shaded area) can be placed. The MPO may exceed 120 db so if the top line of the shaded area can be placed near 118 dB level then the high end of MAOF will be over 1700 Hz for the left ear in my case.

The Enhanced Audibility Extender and Spectral iQ can go lower than Sound Recover 2. The problem is the lack of a decent Widex HA in the ultra power segment, Widex Super is close to ten years old. Starkey offers Muse iQ Power Plus that is an UP aid but AFIK there are some limitations by the software.

One thing about your attached graphs they are not a particular hearing aids manufacturer software. Knowing that it will push gains where your Widex or my Phonak software wouldn’t. So that is not really an issue here.
If you are programming your aids, have you dropped the frequency lowering settings as far as they will go? If you have, do your hear birds or alarms that you couldn’t hear before? That would be a great sign that in time speech would also get better.

Interesting simulation. From your audiogram it seems questionable if frequency lowering would help. However, how well you do with speech understanding doesn’t really coincide with how I would expect you to hear based on your audiogram Frequency lowering should enable you to hear higher frequencies. How much and whether you like it or find it beneficial? Who knows. The only way you’re going to know is to try it.


I thought the same thing about his understanding speech with that audiogram. He is is either telepathic or a really good lip reader.

From what he is saying, he has not used frequency lowering technology yet.

I don’t have any experience with frequency lowering that can go below my MAOF high end frequency. I have tested Resound Enzo Q with Sound Shaper on but it has pretty basic FL with lowest cut-off frequency at 2.5 kH.

I downloaded a Frequency generator app to test the loudness of different frequencies at around 75 dB SPL that corresponds to the upper line of the green shaded area (speech passage at 75 dB SPL). With my old Widexs I can hear sounds that would be of benefit for speech intelligibility up to 1900 Hz for the left and 1500 Hz for the right ear.

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It sure sounds like you would benefit from a good frequency lowering technology. You like Widex, can you give them a try at frequency lowering? They will need to be adjusted to where the S sound lisps. Then wear them until your brain learns and acclimates to the new sounds. It was a struggle with speech for a while but all the new sounds of nature and around the house made it worth it.

It seems Widex is not interested in the UP segment anymore. Their last UP premium HA is Widex Super, released in 2011, almost 10 years ago. Widex also released a budget UP HA in 2012 called Menu with 3, 5 and 10 channels and targeted for India. Audibility Extender is not included in Menu by default, only as add-on. Probably these models are already discontinued.

The Phonak Naida M SP would be a good power aid that has frequency lowering that I know to be very good. The Oticon Exceed could be a good one but the frequency lowering does not go low enough for you.
Do you have a Phonak representative to try the new Naida?

I already requested to test the new Naida Marvel but my audiogram is not fully covered by the fitting range from 800 Hz to 3-4 kHz. In my opinion there is not enough gain to “raise the bar” and increase the MAOF endpoint. Naida B may be a better choice.

You may be right. As a mentioned earlier you might just need to try a couple different aids.
The specs on the Naida M and B are very similar. The Marvel aids do improve speech recognition in my opinion. The Oticon Exceed might be good for you too.
I do believe frequency lowering might really help you.

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I just found an article from 2013 about the effect of Audibility Extender on speech perception especially for profound loss - https://www.tandfonline.com/doi/pdf/10.1179/1557069X11Y.0000000001 .
The results are just too good to be true :slight_smile:. The more profoundly hearing-impaired participants from Group B may not have received sufficient amplification in the low-frequency region to ensure audibility of speech sounds with energy concentrations in the low frequencies. It is clear that the HA used in this experiment (Widex Mind 440) cannot cover the most profoundly impaired cases.
On the other hand Widex Super is designed for low-frequency boost:

There are several other articles in favor of Audibility Extender, some sponsored by Widex…

Well, I now have a new audiogram with better results (added in profile). Maybe I’ll qualify for the Naida Marvel SP? My concern is if the benefit from Sound Recover 2 decrease with the Naida SP aid. Is Naida SP enough powerful for my case or I’ll have to stuck with the UP version?

My opinion only…the Phonak Naida M SP aids would work for you with very aggressive Sound Recover 2 settings.

How much aggressive, below 1.1 Hz the speech intelligibility decreases a lot.

The low cut off for me is 800 hertz. When the S starts lisping I stopped.

Initially I heard birds, crickets, buzzers, smoke alarms, car turn signals for the first time in many years. It was amazing. This kept me going. At this time speech was jarbled and not very clear. It took a couple or three months for speech to start clearing up. Music sounds pretty good too. I have two manual programs, speech in 360 and speech in loud noise do pretty good in loud places.


I’m wondering if the earmold type can expand the max gain of HA with the so called horn effect. Horn effect to increase low or high frequencies can be achieved by using a drilled horn bore, large bore, reverse curve bore etc. It’s not clear if this effect reduces or increases the gain specified in the HA datasheet.

I have read about what you are describing but never heard of anyone getting molds like that. The place I get my molds made does not show anything like this horn design in their showcase.

I suspect you are debating the Naida M SP aids.

It seems that with 3 mm Libby horn I can get 1 dB extra boost after 1400 Hz and up to 5 dB extra boost from 2000 to 3000 Hz. Naida Marvel SP comes with two options for earhooks - damped and undamped. The damper is white in colour that corresponds to 680 Ohms impedance - removing the damper increases the gain from 2 dB up to 11 dB depending on the frequency, with noticeable difference especially at the resonant peaks.

But the standard 2 cc coupler that measures the gain uses a horn tubing too…I’m wondering if the 3 mm Libby is equal to the horn used to measure the official gain?

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