Fresnel aspherical acoustic mirrors
 

Does anyone know of any firms that can design and
manufacture small Fresnel acoustic mirrors with a
specified (non-planar) surface shape ?
My hope is for a new form of hearing aid for those with
mild hearing loss, in which suitably designed shoulder
pads would reflect sounds incident to the front of the
wearer and direct them to foci just outside the ears.
Horses and other animals have wonderful acoustic
reflectors. It's about time we humans devised something
similar - without the user having to look freakish.

Fresnel aspherical acoustic mirrors
 

On 24/10/2012 13:11, Jim Hawkins wrote:

without the user having to look freakish.

Aye, as Hamlet would say, there's the rub.

Fresnel aspherical acoustic mirrors
 

Erm, not sure this would work very well. Surely even if the reflectors did
work, the head turning could upset it rather.
Its not I think going to be any better than cupping the ear with one hand.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Jim Hawkins" wrote in message
...
Does anyone know of any firms that can design and
manufacture small Fresnel acoustic mirrors with a
specified (non-planar) surface shape ?
My hope is for a new form of hearing aid for those with
mild hearing loss, in which suitably designed shoulder
pads would reflect sounds incident to the front of the
wearer and direct them to foci just outside the ears.
Horses and other animals have wonderful acoustic
reflectors. It's about time we humans devised something
similar - without the user having to look freakish.

Fresnel aspherical acoustic mirrors
 

On 24/10/2012 14:37, Brian Gaff wrote:
Erm, not sure this would work very well. Surely even if the reflectors did
work, the head turning could upset it rather.
Its not I think going to be any better than cupping the ear with one hand.

Brian

Perhaps worn as a hat?

Fresnel aspherical acoustic mirrors
 

Phil wrote:
On 24/10/2012 14:37, Brian Gaff wrote:
Erm, not sure this would work very well. Surely even if the
reflectors did work, the head turning could upset it rather.
Its not I think going to be any better than cupping the ear with
one hand. Brian

Perhaps worn as a hat?

Yes - that might be very acceptable for many women.

Fresnel aspherical acoustic mirrors
 

GB wrote:
On 24/10/2012 13:11, Jim Hawkins wrote:

without the user having to look freakish.

Aye, as Hamlet would say, there's the rub.

Bring back ear trumpets I say!

Tim

Fresnel aspherical acoustic mirrors
 

On 24/10/2012 16:32, Jim Hawkins wrote:
Phil wrote:
On 24/10/2012 14:37, Brian Gaff wrote:
Erm, not sure this would work very well. Surely even if the
reflectors did work, the head turning could upset it rather.
Its not I think going to be any better than cupping the ear with
one hand. Brian

Perhaps worn as a hat?

Yes - that might be very acceptable for many women.


You've actually missed the whole point about how hearing aids work, and
why.

As we get older, the ears become less sensitive at high frequencies, but
retain their sensitivity at lower frequencies. Hence, hearing aids don't
just make everything louder. They boost the high frequencies, but not
the lower ones.

You'll need to build that into your hat, or it won't help.

Fresnel aspherical acoustic mirrors
 

On Wednesday, 24 October 2012 13:11:04 UTC+1, Jim Hawkins wrote:
Does anyone know of any firms that can design and
manufacture small Fresnel acoustic mirrors

No - because Fresnel doesn't work in "small". For optics, a convenient size is (optically) "large", so they work. For acoustics, a sensibly sized gadget is going to be (acoustically) small, relative to wavelength. So your gadget is going to suffer from so much diffraction as to stop it working.

Fresnel aspherical acoustic mirrors
 

On 24/10/2012 21:44, Andy Dingley wrote:
On Wednesday, 24 October 2012 13:11:04 UTC+1, Jim Hawkins wrote:
Does anyone know of any firms that can design and
manufacture small Fresnel acoustic mirrors

No - because Fresnel doesn't work in "small". For optics, a convenient size is (optically) "large", so they work. For acoustics, a sensibly sized gadget is going to be (acoustically) small, relative to wavelength. So your gadget is going to suffer from so much diffraction as to stop it working.


Very succinctly put! I'm glad you said that. (I did wonder whether the
OP was confusing Fresnel lenses with diffraction gratings)

Fresnel aspherical acoustic mirrors
 

On Wed, 24 Oct 2012 16:52:40 +0100, Tim+ wrote:

GB wrote:
On 24/10/2012 13:11, Jim Hawkins wrote:

without the user having to look freakish.

Aye, as Hamlet would say, there's the rub.

Bring back ear trumpets I say!

What?

Fresnel aspherical acoustic mirrors
 

Jules Richardson wrote:
On Wed, 24 Oct 2012 16:52:40 +0100, Tim+ wrote:

GB wrote:
On 24/10/2012 13:11, Jim Hawkins wrote:

without the user having to look freakish.

Aye, as Hamlet would say, there's the rub.

Bring back ear trumpets I say!

What?

I SAID, BRING BACK EAR TRUMPETS! ;-)

Tim

Fresnel aspherical acoustic mirrors
 

On Wed, 24 Oct 2012 13:44:52 -0700 (PDT), Andy Dingley
wrote:

For acoustics, a sensibly sized gadget is going to be (acoustically) small, relative to wavelength.

May I respectfully suggest:

http://en.wikipedia.org/wiki/File:Wartuba.jpg


Oh, sorry missed the "sensibly"...


Thomas Prufer

Fresnel aspherical acoustic mirrors
 

On 24/10/2012 13:47, GB wrote:
On 24/10/2012 13:11, Jim Hawkins wrote:

without the user having to look freakish.

Aye, as Hamlet would say, there's the rub.

Don't you think someone with massive acoustically reflecting shoulder
pads is going to look pretty silly? And still a very limited gain.

Modern digital hearing aids are now incredibly good. You can't compete.
The improvements in DSP technology have overtaken my dad's hearing loss.
He can now hear in both ears again!

--
Regards,
Martin Brown

Fresnel aspherical acoustic mirrors
 

In article ,
Martin Brown wrote:
On 24/10/2012 13:47, GB wrote:
On 24/10/2012 13:11, Jim Hawkins wrote:

without the user having to look freakish.

Aye, as Hamlet would say, there's the rub.

Don't you think someone with massive acoustically reflecting shoulder
pads is going to look pretty silly?

ever heard of "fashion"? Lots of things people wear look 'pretty silly'.

--
From KT24

Using a RISC OS computer running v5.18

Fresnel aspherical acoustic mirrors
 

On 25/10/2012 09:16, charles wrote:
In article ,
Martin Brown wrote:
On 24/10/2012 13:47, GB wrote:
On 24/10/2012 13:11, Jim Hawkins wrote:

without the user having to look freakish.

Aye, as Hamlet would say, there's the rub.

Don't you think someone with massive acoustically reflecting shoulder
pads is going to look pretty silly?

ever heard of "fashion"? Lots of things people wear look 'pretty silly'.

No. I never was very fashionable...

--
Regards,
Martin Brown

Fresnel aspherical acoustic mirrors
 

It's an interesting notion but surely impractical, I'm afraid: quite apart
from the need to boost only higher frequencies, the angling required would
make any shoulder pads a very odd shape indeed.

Modern hearing aids are small, self-contained, hard to spot, very efficient
and even programmable with different frequency responses for differing
conditions. And available free on the NHS. That's tough competition.

But good luck.

Fresnel aspherical acoustic mirrors
 

"Martin Brown" wrote in message ...

On 24/10/2012 13:47, GB wrote:
On 24/10/2012 13:11, Jim Hawkins wrote:

without the user having to look freakish.

Aye, as Hamlet would say, there's the rub.

Don't you think someone with massive acoustically reflecting shoulder
pads is going to look pretty silly? And still a very limited gain.

Modern digital hearing aids are now incredibly good. You can't compete.
The improvements in DSP technology have overtaken my dad's hearing loss.
He can now hear in both ears again!


He'd be really popular with the ladies if he could breathe through them.

Fresnel aspherical acoustic mirrors
 

On Wednesday, October 24, 2012 9:44:52 PM UTC+1, Andy Dingley wrote:
No - because Fresnel doesn't work in "small". For optics, a convenient size is (optically) "large", so they work. For acoustics, a sensibly sized gadget is going to be (acoustically) small, relative to wavelength. So your gadget is going to suffer from so much diffraction as to stop it working.


but it will work at high frequencies and that's just where you need to increase the signal. wavelength is 8cm at 4kHz

Robert

Fresnel aspherical acoustic mirrors
 

On Thu, 25 Oct 2012 07:36:06 +0100, Tim+ wrote:

Jules Richardson wrote:
On Wed, 24 Oct 2012 16:52:40 +0100, Tim+ wrote:

GB wrote:
On 24/10/2012 13:11, Jim Hawkins wrote:

without the user having to look freakish.

Aye, as Hamlet would say, there's the rub.

Bring back ear trumpets I say!

What?

I SAID, BRING BACK EAR TRUMPETS! ;-)

:-)

There are some real gems he

http://www.moolf.com/interesting/biz...ices-used-for-
hearing-airplanes-in-wwii.html

Fresnel aspherical acoustic mirrors
 

Martin Brown wrote:
On 24/10/2012 13:47, GB wrote:
On 24/10/2012 13:11, Jim Hawkins wrote:

without the user having to look freakish.

Aye, as Hamlet would say, there's the rub.

Don't you think someone with massive acoustically reflecting shoulder
pads is going to look pretty silly? And still a very limited gain.

Modern digital hearing aids are now incredibly good. You can't
compete. The improvements in DSP technology have overtaken my dad's
hearing loss. He can now hear in both ears again!


Where did you get the 'massive. from ? Not from my post!
I envisage them being slightly bigger than the shoulder pads in suits,
but like them, worn inside, and so quite invisible.
And I did say 'for those with MILD hearing loss'.
Even the latest ITE (in-the-ear) devices deliver what I consider to be an
unacceptably poor signal/noise ratio - and are much too expensive. for
many people.
You may not realise that Fresnel mirrors (acoustic as well as optical)
can be of any external shape. It's only the individual reflecting sectors
that are angled to reflect into the required focus area.
As they would comprise only plastic mouldings, they would be cheap,
reliable, and leave the ears free.
Bone conduction (BTE) devices are, in my opinion, already more effective
than the ITE devices - and are improving. But they too are fragile high-tech
electronic devices, and don't come cheap.

Fresnel aspherical acoustic mirrors
 

Bert Coules wrote:
It's an interesting notion but surely impractical, I'm afraid: quite
apart from the need to boost only higher frequencies, the angling
required would make any shoulder pads a very odd shape indeed.

No. Fresnel mirrors can be of arbitrary external shape, and so could
fit the shoulders in exactly the same way as ordinary shoulder pads.

Modern hearing aids are small, self-contained, hard to spot, very
efficient and even programmable with different frequency responses
for differing conditions. And available free on the NHS. That's
tough competition.

If only all that were true !

Fresnel aspherical acoustic mirrors
 

On 25/10/2012 18:44, Jim Hawkins wrote:
Bert Coules wrote:
It's an interesting notion but surely impractical, I'm afraid: quite
apart from the need to boost only higher frequencies, the angling
required would make any shoulder pads a very odd shape indeed.

No. Fresnel mirrors can be of arbitrary external shape, and so could
fit the shoulders in exactly the same way as ordinary shoulder pads.

Modern hearing aids are small, self-contained, hard to spot, very
efficient and even programmable with different frequency responses
for differing conditions. And available free on the NHS. That's
tough competition.

If only all that were true !


And which bit is NOT true?

I do have to wonder about "hard to spot", but compared to the huge lump
my grandmother had hanging from a clip, nearly continuously emitting
very loud, piercing noises, it is at least arguable.

--
Rod

Fresnel aspherical acoustic mirrors
 

On Wed, 24 Oct 2012 19:05:00 +0100, GB
wrote:

You've actually missed the whole point about how hearing aids work, and
why.

As we get older, the ears become less sensitive at high frequencies, but
retain their sensitivity at lower frequencies. Hence, hearing aids don't
just make everything louder. They boost the high frequencies, but not
the lower ones.

You'll need to build that into your hat, or it won't help.

Pah, trivially easy.
Russian fur hat with the flaps down or simple baseball cap with
extensions out to the lower sides, cunningly shaped as cartoon
characters to attract the local idiots.

Fresnel aspherical acoustic mirrors
 

On Thu, 25 Oct 2012 18:34:35 +0100, "Jim Hawkins"
wrote:

Bone conduction (BTE) devices are, in my opinion, already more effective
than the ITE devices - and are improving. But they too are fragile high-tech
electronic devices, and don't come cheap.

I'm reminded of the BoneFone, as advertised in Omni magazine in the
late 70s. The wearer draped it around their shoulders and it
transmitted the sound to the ears via the collar bone, neck and skull.
Crackpot idea, but sold well enough until people realised they looked
like ****s.

Fresnel aspherical acoustic mirrors
 

On 27/10/2012 20:50, Grimly Curmudgeon wrote:
Pah, trivially easy.
Russian fur hat with the flaps down or simple baseball cap with
extensions out to the lower sides, cunningly shaped as cartoon
characters to attract the local idiots.


FA: Woolly hat with inbuilt headphones. Came as a package with a camera
we bought in Spain after I left mine at home...

Andy