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Home > Archive > Hearing loss support > August 2006 > Technical question re: flat audiogram
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Technical question re: flat audiogram
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| Mason C 2006-07-20, 9:24 pm |
| I have what seems a pertinent question for this group.
What do expensive digital hearing aids do beyond what
a frequency-corrected analog amplifier will do?
In particular, for a flat audiogram, wouldn't a $30 amplifier do
the job? There are several on the market, including BTE.
What would a $2,000 hearing aid do that such a $30
"hearing assistance" would not do, especially for a
flat audiogram?
I've not been able to find a technical description or
specification sheet that answers this question fully.
(1) anti-feedback circuitry
(2) perhaps directional microphone
(3) properly fitted earpiece
(4)
(5)
(6)
I *suspect* there is more that the hearing-aid sellers
do not describe because too technical for most buyers.
Mason C
| |
|
| Mason C wrote:
> I have what seems a pertinent question for this group.
>
> What do expensive digital hearing aids do beyond what
> a frequency-corrected analog amplifier will do?
>
> In particular, for a flat audiogram, wouldn't a $30 amplifier do
> the job? There are several on the market, including BTE.
>
> What would a $2,000 hearing aid do that such a $30
> "hearing assistance" would not do, especially for a
> flat audiogram?
>
> I've not been able to find a technical description or
> specification sheet that answers this question fully.
>
> (1) anti-feedback circuitry
> (2) perhaps directional microphone
> (3) properly fitted earpiece
> (4)
> (5)
> (6)
>
> I *suspect* there is more that the hearing-aid sellers
> do not describe because too technical for most buyers.
>
> Mason C
As I see it, these are the main things most modern hearing aids try to
do:
1. Amplify sound.
2. Reduce the sense you might have of something plugging up your ear
and causing you to hear your own voice loudly (occlusion).
3. Shape the frequency response of the amplification to correct for
your (non-flat) hearing loss. (equalization)
4. Automatically reduce the amplification when sounds get too loud for
you - in each frequency channel. (compression)
5. Listen for non-voice like sounds in each frequency band and when
found, automatically reduce the gain for that band. (noise reduction).
6. Detect when the output sound produced by the hearing aid is picked
up by it's own microphone to a degree that would cause squealing and
then automatically change it or cancel some of it out. (feedback
reduction)
7. Using multiple microphones, combine their outputs so that sound in
front of you is amplified more than sound not in front of you.
(directional mode)
The items above that contain the word "automatically" imply that the
hearing aid has to figure out when these things need to be done and to
do them. These items (while sometimes beneficial) always seem to take
some toll on sound quality or add some sound artifact of their own in
the process. The balance of advantages versus degradation is different
for each design and is not something that will show up in any spec
sheet.
| |
| Xu Zhian Wen 2006-07-20, 9:24 pm |
| Mason C wrote:
> I have what seems a pertinent question for this group.
>
> What do expensive digital hearing aids do beyond what
> a frequency-corrected analog amplifier will do?
>
> In particular, for a flat audiogram, wouldn't a $30 amplifier do
> the job? There are several on the market, including BTE.
>
> What would a $2,000 hearing aid do that such a $30
> "hearing assistance" would not do, especially for a
> flat audiogram?
>
> I've not been able to find a technical description or
> specification sheet that answers this question fully.
>
> (1) anti-feedback circuitry
> (2) perhaps directional microphone
> (3) properly fitted earpiece
> (4)
> (5)
> (6)
>
> I *suspect* there is more that the hearing-aid sellers
> do not describe because too technical for most buyers.
>
> Mason C
I mostly repair hearing aids but I think that's a good question that I
would like to know the answer to. I've been asked about these devices
and my answer is that they should try them out and let me know as
there's not much money involved so why not? That's pretty much my
response to your question as you're in a better position to find out how
effective the $30 hearing thingies are. I've yet to get any feedback on
these so that info is sketchy.
As far as the expensive stuff is concerned, I believe that aids will go
to the next step of features in that they will be connected devices that
work together, preserving spacial and timing information - you know how
a binaural set will give you the feeling of being in a small space? I'm
hoping this feature will solve that. Another new feature is VC logging
that learns/programs gain preferences in different situations. You
probably won't find these features in a $2000 hearing aid but my gut
feeling is they'll be standard on future aids.
| |
|
| Hi Mason,
Are you having difficulty understanding speech? A fully programmed digital
hearing aid, not only gives you amplification, it will give you clarity as
well. As the aid will be able to "sharpen" the sound making speech, in
particular, easier to understand. This will help eliminate the danger of
over amplification and hence, further hearing loss caused by excessive
noise. For example, if someone is a mumbler, it won't be any easier for you
to understand them, if they simply mumble louder. You need some element of
clarity too. And if you are using a analog amplifier all day, every day, you
will be at risk of noise induced hearing loss, compounding any existing
loss.
Hope this makes sense.
Maree
"Mason C" <masonc2@earthlink.net> wrote in message
news:ga50c2ds7easjgoov8rc5ql3fdkmeac5uq@4ax.com...
> I have what seems a pertinent question for this group.
>
> What do expensive digital hearing aids do beyond what
> a frequency-corrected analog amplifier will do?
>
> In particular, for a flat audiogram, wouldn't a $30 amplifier do
> the job? There are several on the market, including BTE.
>
> What would a $2,000 hearing aid do that such a $30
> "hearing assistance" would not do, especially for a
> flat audiogram?
>
> I've not been able to find a technical description or
> specification sheet that answers this question fully.
>
> (1) anti-feedback circuitry
> (2) perhaps directional microphone
> (3) properly fitted earpiece
> (4)
> (5)
> (6)
>
> I *suspect* there is more that the hearing-aid sellers
> do not describe because too technical for most buyers.
>
> Mason C
| |
| Mason C 2006-07-21, 8:25 am |
| On Fri, 21 Jul 2006 07:31:32 GMT, "maree" <mareelm@bigpond.com.au> wrote:
>Hi Mason,
>
>Are you having difficulty understanding speech? A fully programmed digital
>hearing aid, not only gives you amplification, it will give you clarity as
>well. As the aid will be able to "sharpen" the sound making speech, in
>particular, easier to understand. This will help eliminate the danger of
>over amplification and hence, further hearing loss caused by excessive
>noise. For example, if someone is a mumbler, it won't be any easier for you
>to understand them, if they simply mumble louder. You need some element of
>clarity too. And if you are using a analog amplifier all day, every day, you
>will be at risk of noise induced hearing loss, compounding any existing
>loss.
>
>Hope this makes sense.
>
>Maree
Thanks but for me not quite.
I understand frequency compensation and that the enhancement of lost
highs will help in word recognition -- hearing the consonants..
But for a flat audiogram I assume that highs would not be enhanced.
Is there some other digital-aid mechanism for "clarity" and "sharpen"?
Mason C
>
>
>"Mason C" <masonc2@earthlink.net> wrote in message
>news:ga50c2ds7easjgoov8rc5ql3fdkmeac5uq@4ax.com...
>
| |
| Paul Revere 2006-07-21, 8:25 am |
|
"jim" <jwcrim@gmail.com> wrote in message
news:1153441873.105827.86020@m73g2000cwd.googlegroups.com...
:
: As I see it, these are the main things most modern
hearing aids try to
: do:
:
: 1. Amplify sound.
: 2. Reduce the sense you might have of something
plugging up your ear
: and causing you to hear your own voice loudly
(occlusion).
: 3. Shape the frequency response of the amplification
to correct for
: your (non-flat) hearing loss. (equalization)
: 4. Automatically reduce the amplification when sounds
get too loud for
: you - in each frequency channel. (compression)
: 5. Listen for non-voice like sounds in each frequency
band and when
: found, automatically reduce the gain for that band.
(noise reduction).
: 6. Detect when the output sound produced by the
hearing aid is picked
: up by it's own microphone to a degree that would
cause squealing and
: then automatically change it or cancel some of it
out. (feedback
: reduction)
: 7. Using multiple microphones, combine their outputs
so that sound in
: front of you is amplified more than sound not in
front of you.
: (directional mode)
:
: The items above that contain the word "automatically"
imply that the
: hearing aid has to figure out when these things need
to be done and to
: do them. These items (while sometimes beneficial)
always seem to take
: some toll on sound quality or add some sound artifact
of their own in
: the process. The balance of advantages versus
degradation is different
: for each design and is not something that will show
up in any spec
: sheet.
:
Another feature I enjoy is multiple programs selected
by pushing a button.
*I have one program set for omni directional max gain.
I use this while not listening to anything particular.
*I have another program for directional listening. The
HF is cranked up more here and I listen to music and TV
as well as have conversations with it. There is more
noise with the directional mode than the omni, just
like there is more noise with a cardioid microphone
than with an omni.
* I have the third program almost off. This way I can
hear the phone without feedback and I have a place to
go when rap music or annoying kids screaming floods the
air.
peace
Paul Revere
| |
| kol_Isha 2006-07-21, 8:25 am |
|
"Mason C" <masonc2@earthlink.net> wrote in message
news:ke41c21qpve7aoikpmeolg1ohqvjd2dop3@4ax.com...
> On Fri, 21 Jul 2006 07:31:32 GMT, "maree" <mareelm@bigpond.com.au> wrote:
>
>
> Thanks but for me not quite.
>
> I understand frequency compensation and that the enhancement of lost
> highs will help in word recognition -- hearing the consonants..
>
> But for a flat audiogram I assume that highs would not be enhanced.
>
> Is there some other digital-aid mechanism for "clarity" and "sharpen"?
>
> Mason C
I am following this conversation closely, as I had asked the same question
as Mason, and at this point I'm even more confused than ever. I also have a
flat audiogram (pretty much 45 db loss across all frequencies, slightly
higher at about 8000 Hertz). I am getting digital aids. I had asked, at
the onset of this process, whether or not there was any possibility that
aids would somehow "overamplify and cause further hearing loss" and if I
recall, was reassured that aids could only help and that they do not cause
you to lose your hearing further. I AM concerned about this because,
although I struggle to hear soft conversations, I hate loud noises and seem
more sensitive to loudness than the average person. So if I'm suddenly
wearing hearing aids and the sound of a dripping faucet (which I normally
cannot hear) sounds like the roaring of a train, I am NOT going to be happy.
Also, clarity generally is not a problem for me. According to my audiogram
and evaluation, I have "excellent word recognition" at "above normal
conversation levels." My word recognition score is 92% in one ear and 100%
in the other, at 85 dbHL. And it is true that as long as you speak loud
enough, I can understand everything. So now... I am beginning to wonder if
I am attempting to kill a fly with a cannon instead of a flyswatter.
Regards,
Arlene
| |
| Peter Weis 2006-07-22, 8:27 am |
| Mason C wrote:
> I understand frequency compensation and that the enhancement of lost
> highs will help in word recognition -- hearing the consonants..
>
> But for a flat audiogram I assume that highs would not be enhanced.
There's two different philosophies in hearing aid fitting, and the score
seem to be almost even.
One is called Loudness Normalisation, and it tents to restore the
loudness of sound over the frequency range.
The other is called Loudness Equalization, and it tents to reproduce
speech components over the frequency range at equal loudness.
The former might have an edge in general listening, and the latter while
listening to speech.
For a flat audiogram, the highs won't be enhanced when using the
normalisation philosophy, while that will not be the case for the
equalization philosophy. It does however depend a bit on the
implementation of filters bandwidths, the voice activity detectors etc.
bets regards
Peter
| |
| Peter Weis 2006-07-22, 8:27 am |
| kol_Isha wrote:
> I am following this conversation closely, as I had asked the same question
> as Mason, and at this point I'm even more confused than ever. I also have a
> flat audiogram (pretty much 45 db loss across all frequencies, slightly
> higher at about 8000 Hertz). I am getting digital aids. I had asked, at
> the onset of this process, whether or not there was any possibility that
> aids would somehow "overamplify and cause further hearing loss" and if I
> recall, was reassured that aids could only help and that they do not cause
> you to lose your hearing further.
There is generally a small risk. A bit like secondary effect by taking
drugs.
It depends, as for people without hearing loss, on the sound levels you
are listening to.
Hearing aids with good recruitment compensation are better than linear
hearing aids, as they lower the amplification as the sound level goes up.
> I AM concerned about this because,
> although I struggle to hear soft conversations, I hate loud noises and seem
> more sensitive to loudness than the average person.
With a hearing loss of 45 dB, your amplifiction should be moderate only
and real risk rather limited.
Don't be araid of amplifying soft conversations. The sound level is so
low that even if you amplify, it is not likely to reach critical output
levels.
As for loud sounds being too loud, go have the hearing aids adjusted to
cut the loud sounds. They are the potentially harmfull ones.
best regards
Peter
| |
| kol_Isha 2006-07-22, 4:24 pm |
|
"Peter Weis" <p.weis@email.dk.slet> wrote in message
news:44c2023a$0$60785$157c6196@dreader1.cybercity.dk...
>
> There is generally a small risk. A bit like secondary effect by taking
> drugs.
> It depends, as for people without hearing loss, on the sound levels you
> are listening to.
> Hearing aids with good recruitment compensation are better than linear
> hearing aids, as they lower the amplification as the sound level goes up.
>
> With a hearing loss of 45 dB, your amplifiction should be moderate only
> and real risk rather limited.
>
> Don't be araid of amplifying soft conversations. The sound level is so
> low that even if you amplify, it is not likely to reach critical output
> levels.
> As for loud sounds being too loud, go have the hearing aids adjusted to
> cut the loud sounds. They are the potentially harmfull ones.
>
> best regards
> Peter
Thank you, Peter.  An answer that I can actually understand.
Regards,
Arlene
| |
| schnappize 2006-08-01, 2:26 am |
|
Peter Weis wrote:
> kol_Isha wrote:
>
>
> There is generally a small risk. A bit like secondary effect by taking
> drugs.
> It depends, as for people without hearing loss, on the sound levels you
> are listening to.
> Hearing aids with good recruitment compensation are better than linear
> hearing aids, as they lower the amplification as the sound level goes up.
>
>
> With a hearing loss of 45 dB, your amplifiction should be moderate only
> and real risk rather limited.
>
> Don't be araid of amplifying soft conversations. The sound level is so
> low that even if you amplify, it is not likely to reach critical output
> levels.
> As for loud sounds being too loud, go have the hearing aids adjusted to
> cut the loud sounds. They are the potentially harmfull ones.
>
> best regards
> Peter
| |
| schnappize 2006-08-01, 2:26 am |
| Hi, I also currently wear hearing aids in both ears, I prefer the aids
as they do amplfy conversation that is spoken in soft tones without
feedback, I own a pair of sienmens aid the kind that fit in the canal
of your ear. The only thing I cannot take is really loud music as the
only thing I hear is that an can't hear someone trying to talk to me
if they are standing next to me. Also I did not pay 2000 dollars per
aid, the smaller you go the more expensive they are. Mine were about
500 a piece, which ifyour a us resident you can probally take off your
income tax for medical expenses. I currently by batteries off of ebay
much much cheaper than the store.
maree wrote:[vbcol=seagreen]
> Hi Mason,
>
> Are you having difficulty understanding speech? A fully programmed digital
> hearing aid, not only gives you amplification, it will give you clarity as
> well. As the aid will be able to "sharpen" the sound making speech, in
> particular, easier to understand. This will help eliminate the danger of
> over amplification and hence, further hearing loss caused by excessive
> noise. For example, if someone is a mumbler, it won't be any easier for you
> to understand them, if they simply mumble louder. You need some element of
> clarity too. And if you are using a analog amplifier all day, every day, you
> will be at risk of noise induced hearing loss, compounding any existing
> loss.
>
> Hope this makes sense.
>
> Maree
>
>
> "Mason C" <masonc2@earthlink.net> wrote in message
> news:ga50c2ds7easjgoov8rc5ql3fdkmeac5uq@4ax.com...
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