If someone has 70db HL and gets 70db HA gain, does he hear 0db?

bump, learning more all the time!

@xbulder said:

pretty much no one uses adro anymore.

the old savia used to, now they have steer away…

Savia is not an adro hearing aid.

Kind regards,

Leia

What if the hearing loss at a certain frequency is already at NR (like my case) does it mean you can apply your preferred gain?

We know that, beyond certain threshold there is no use in using amplification
because that cochlear zone is dead. the ideal option is to use either frequency
compresion or frequency transposition. Avr Sono had been doing freq compr for a very very long time. Phonak had popularized frequency compre. and it calls it sound recover.

Widex, had used freque. transposition in their inteo line for quite some time-
Im not sure they have been that sucessful. Most people reject transposition and it
requires a adaptation time… But the results are promising…

We are approaching the 2nd wireless products from phonak, siemens and Oticon.
I would expect siemens and Oticon to consider some sort of frequency transposition
products. We would know in april …

The big thing to remember about gain is that it is an amount of additional volume for any given input (or output depending on the hearing aid). So, if you have 30dB of gain it doesn’t mean you are hearing sounds at 30dB…it means that you are hearing sounds 30dB above a specific input of sound. For example, say our hearing aid looks at gain for 3 input levels, 40dB, 60dB, and 90dB. If we just looked at the middle one, 60dB, and assumed a 30dB gain amount, that means sounds at that frequency would be heard by the wearer at 90dB (60+30). So if you had a hearing loss of 75dB at 3000Hz, and had gain of 30dB at 3000Hz, a sound at 60dB at 3000Hz would be heard at 90dB which is 15dB above the wearers threshold and should be easily audible. Now this is very simplistic but illustrates the concept of gain and how it works/is applied.

This may become more understandable next week when I get my first ever pair of HAs.

For someone with my hearing loss chart I do not understand why HAs cannot just act as small equalizers and simply boost the volume of a certain range of high frequencies.

I think my chart means I can still hear certain high frequencies but for instance, at 8000 they have to be 80dB louder than for a “normal” person. So if the hearing aid were able to boost sounds in the 8000 frequency range by 80dB without too much distortion or feedback then I would hear them and all would be well.

As I understand the Phonak SoundRecover feature it transposes high frequencies to a mid range one and mid range ones to lower ones and compresses the difference to fit the high ranges progressively into the lower ranges whereas other HAs simply transpose them so that high and mid range sounds are both duplicatively heard as the same mid range sounds. I am not sure I am going to like this which is why I checked whether this feature could be turned off. I think I would like the simple transposition even less. I wish that simple equalization worked. But until I get my HAs I won’t know.

@TambourineMan said:

This may become more understandable next week when I get my first ever pair of HAs.

For someone with my hearing loss chart I do not understand why HAs cannot just act as small equalizers and simply boost the volume of a certain range of high frequencies.

I think my chart means I can still hear certain high frequencies but for instance, at 8000 they have to be 80dB louder than for a “normal” person. So if the hearing aid were able to boost sounds in the 8000 frequency range by 80dB without too much distortion or feedback then I would hear them and all would be well.

As I understand the Phonak SoundRecover feature it transposes high frequencies to a mid range one and mid range ones to lower ones and compresses the difference to fit the high ranges progressively into the lower ranges whereas other HAs simply transpose them so that high and mid range sounds are both duplicatively heard as the same mid range sounds. I am not sure I am going to like this which is why I checked whether this feature could be turned off. I think I would like the simple transposition even less. I wish that simple equalization worked. But until I get my HAs I won’t know.

You are not applying gain correctly. We don’t use 0dB HL as a reference for gain. Gain is an amount of amplification over a certain input or output so if you have an input of 60dBHL and you had 80dB of gain, the sound would be 140dB HL…so that obviously doesn’t work. Also, the goal of hearing aids isn’t to try to get your hearing thresholds to 0dB…it’s to restore hearing to an audible level for normal conversational speech…so usually if we do aided testing after, thresholds are usually 15-30dB HL because normal conversational speech happens around 55dBHL. Here’s another kicker…hearing aids function in dB SPL and not HL which is an artificial scale created so that hearing within normal levels it can be plotted in a nice, straight line (because everyone likes straight lines).

But wait, THERE’S MORE!!! Hearing loss in the high frequency range results from outer hair cell damage. If there is enough hair cell damage it results in essentially dead areas of the cochlea, so it doesn’t matter if you could generate a million dB of gain, there’s nothing there to send the signal to the brain. Soundrecover takes the sounds that would potentially fall in the cochlear dead regions and compresses them to an area where there could potentially be some lingering functional hair cells allowing the wearer to hear that /s/ sound whereas before they might not be able to.

To simplify a hearing aid, it is basically a very high -tech equalizer…applying amplification of varying amounts where you need it plus tons of other features like noise reduction and all those other fancy things you get with hearing aids.

From a previous thread:

OK, it comes down to the application of gain.

First you have to understand that these numbers we throw around on here 80-90-100 dB aren’t a linear scale. To put it simply, if one speaker puts out 80dB and you put another speaker right next to it you produce a whopping 83dB. So a doubling of ‘power’ equates to a 3dB rise in measured output.

The next thing to take into the equation is that there’s a reasonability test applied to gain which forms the basis of all gain calculations. IE: how much sound is ‘needed’ to hear whilst staying within people’s UCL or uncomfortable loudness levels.

The third aspect is that the inputs we have been discussing (speech) aren’t 65dB AVERAGE, they are 65 dB ‘peak’ value. The average value is about 30-40dB depending on the mix of ambient and speech proportion.

The fourth part of this is that given all of the above, engineers determined in the 50’s 60’s 70’s 80’s and 90’s refinements to the basic concepts so that you don’t break some fairly fundamental ‘rules’ of gain.

Namely: 1/2 gain and 1/3 gain rules, basically that if you have a conductive hearing loss, you will receive Half that amount back in gain, at the appropriate frequencies. If you have sensorineural loss, that will be 1/3 or less. Now in our fancy digital age, there are systems that deviate from this to an extent, but that’s the basic precept.

So, if you have a 60dB loss, on average, you’ll get 20dB gain on average. Which, even on a 65dB input signal doesn’t put you anywhere near the 85dB (Aleq), simply because the average dose of continuous speech at 85dB is going to be around 40-50dB. Any more than this is going to do your swede in as you’ll get Auditory Fatigue from the long term exposure.

To combat this, for the last couple of decades hearing aids have been built with circuits that incorporate compression - compression is a technique which allows louder sounds to be given less gain while still amplifying the quieter ones. This has the beneficial effect of making the quieter sounds audible but not blowing your head off with the louder sounds. Now, you’ll hear some people saying that compression is bad, and linearity is good, especially for music. Yes, this is true to an extent, but, non-believers, listen-up! you’ve had some degree of compression in your analogue aids for years - go and dig out the old Gennum and K-Amp specs if you like - or even ask Mead Killion (if he’s still going around on his unicycle…) Basically all circuits compress the output to some extent to avoid the receiver clipping - overdrive distortion on the sound. ~(output-limiting compression)

And finally, just when you think that the manufacturers are really going to do you down, we have software. All the stuff you can see, and all the stuff you cant. Here’s a thought: wouldn’t it be a really good idea to put a limiter into ALL hearing aids? Just to keep the Lawyers happy and to stop self-programmers from really doing damage? Well, what if we put in default UCL limiters at 105-110dB? So that the peak values of the output wouldn’t do any real harm…You can override them of course, but that’s at your risk.

Just think, if somebody fires a gun near your head with occluding hearing aids in - you’ll experience less hearing damage than the person who fired it…

So, there it is, in a nutshell. Hearing aids listening to speech are unlikely to damage your hearing further. I hope that doesn’t sound too patronising. If you want more info, try to get hold of the excellent book: Hearing Aids by Harvey Dillon or Andi VonLanthen’s one.

So I got my first ever HAs this morning (Naida S IX CRTs). Greatest things since sliced bread.

Anyway regarding SoundRecover it has to be on or off for all the four automatic transition programs, but it can be selectively on or off for a manual program.

So initially I have a manual music program with all the same settings as the automatic music program except sound recover is off. I don’t know yet which I will like, but I am happy it is doable.