[jason]

I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

Does someone in this august crowd have experience with such
systems? Recommendations? Potential pitfalls?

Thanks,
Jason

[Mike Rivers[_2_]]

On 3/2/2016 2:25 PM, Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

I'm not an authority on this, but it's been my impression for the past
few years that induction loop "T-coil compatible" systems are on the way
out. What seems to be on the way in are short range WiFi based systems
that people can listen to with their smart-ish phones. These systems are
starting to show up in sports bars with a couple of dozen TV sets on
each wall, allowing the patrons to "tune in" to any channel that they
want to watch.

It's probably worth asking the patrons, particularly if it's a small
community, what capabilities they currently have for assisted hearing
now, and if they have WiFi phones or tablets that work with their
hearing condition. Hearing aids are very different these days than they
were 50, or even 20 years ago. I don't know if these new digital in-ear
hearing aids even have induction loop capability.

--
For a good time, visit http://mikeriversaudio.wordpress.com

[geoff]

On 3/03/2016 9:16 a.m., Mike Rivers wrote:
On 3/2/2016 2:25 PM, Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

I'm not an authority on this, but it's been my impression for the past
few years that induction loop "T-coil compatible" systems are on the
way out. What seems to be on the way in are short range WiFi based
systems that people can listen to with their smart-ish phones. These
systems are starting to show up in sports bars with a couple of dozen
TV sets on each wall, allowing the patrons to "tune in" to any channel
that they want to watch.

It's probably worth asking the patrons, particularly if it's a small
community, what capabilities they currently have for assisted hearing
now, and if they have WiFi phones or tablets that work with their
hearing condition. Hearing aids are very different these days than
they were 50, or even 20 years ago. I don't know if these new digital
in-ear hearing aids even have induction loop capability.


Induction-loop hearing assistance systems are very much mainstream, and
are incorporated into the majority of existing hearing aids. Not sure
what the situation is with the latest generation. Hearing loops are
mandatory in some areas of many public buildings in some jurisdictions.
Newer technologies (IR , Bluetooth, etc) are likely to be in addition to
the loop systems for quite some time I suspect.

Try http://www.hearingloop.org/ - a bit dated though ....

Here's a major manufacturer's FAQ:
http://www.ampetronic.co/FAQ

geoff

[JackA]

On Wednesday, March 2, 2016 at 2:25:44 PM UTC-5, Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

Does someone in this august crowd have experience with such
systems? Recommendations? Potential pitfalls?

Thanks,
Jason

Never heard of this. Sounds like an outdated means of transmission. But, I see for about $200 you can purchase the transmitter. I'm not sure it is 100% analog, but, if so, that would bother me, due to interference. Telecoil = T-coil.

[Scott Dorsey]

Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

Does someone in this august crowd have experience with such
systems? Recommendations? Potential pitfalls?

I have set them up, and they aren't difficult if you follow the rules.
They are less and less popular these days but they are still pretty
commonly installed at big events.

I believe there is good information in the Yamaha Sound Reinforcement
book on laying them out. The secret is to lay the wires out so that
you get even field across the room without hot spots and cold spots
in too many places.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Mike Duffy[_2_]]

On Wed, 2 Mar 2016 16:43:32 -0800 (PST), JackA wrote:

On Wednesday, March 2, 2016 at 2:25:44 PM UTC-5, Jason wrote:

... renovation.

... Sounds like an outdated means of transmission.

Put a streaming audio server onto your WiFi subnet.

[jason]

On Thu, 3 Mar 2016 10:08:03 +1300 "geoff" wrote
in article
Here's a major manufacturer's FAQ:
http://www.ampetronic.co/FAQ


Thanks, geoff and Mike. I suspect the intended beneficiaries of such a
system are not red-hot smartphone savvy, 'tho it seems like everybody
these days has a tablet. More research required.

Jason

[Trevor]

On 3/03/2016 7:16 AM, Mike Rivers wrote:
On 3/2/2016 2:25 PM, Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

I'm not an authority on this, but it's been my impression for the past
few years that induction loop "T-coil compatible" systems are on the way
out. What seems to be on the way in are short range WiFi based systems
that people can listen to with their smart-ish phones. These systems are
starting to show up in sports bars with a couple of dozen TV sets on
each wall, allowing the patrons to "tune in" to any channel that they
want to watch.

It's probably worth asking the patrons, particularly if it's a small
community, what capabilities they currently have for assisted hearing
now, and if they have WiFi phones or tablets that work with their
hearing condition. Hearing aids are very different these days than they
were 50, or even 20 years ago. I don't know if these new digital in-ear
hearing aids even have induction loop capability.

Not all hearing aid wearers can afford new aids every few years to keep
up with the latest trends, and many older people are not interested in
Hi Tech solutions anyway. T-coil is still very common inclusion on most
aids, even if they have blu-tooth, wi-fi, or any other capabilities.
The mandated standard here is still inductive loop systems, and any
thing else would be additional, not an alternative. That *may* change
one day of course.

Trevor.

[geoff]

On 3/03/2016 4:26 p.m., Trevor wrote:
digital in-ear
hearing aids even have induction loop capability.

Not all hearing aid wearers can afford new aids every few years to
keep up with the latest trends, and many older people are not
interested in Hi Tech solutions anyway. T-coil is still very common
inclusion on most aids, even if they have blu-tooth, wi-fi, or any
other capabilities.
The mandated standard here is still inductive loop systems, and any
thing else would be additional, not an alternative. That *may* change
one day of course.

Trevor.

I suspect they are *the* standard in UK and rest of EU as well. Dunno
about US ...

I've got a bin of flat 'under-carpet' cable here, for testing ones that
I repair ;-)

geoff

[jason]

On 2 Mar 2016 20:04:21 -0500 "Scott Dorsey" wrote in
article
I believe there is good information in the Yamaha Sound Reinforcement
book on laying them out. The secret is to lay the wires out so that
you get even field across the room without hot spots and cold spots
in too many places.


Thanks for reminding me. I have the book. The room is not a stadium venue
by any means - it's about 30x40.

[jason]

On Wed, 2 Mar 2016 20:15:52 -0500 "Mike Duffy"
wrote in article
Put a streaming audio server onto your WiFi subnet.


We could do both. The library has excellent WiFi. Adding a streamer
wouldn't be difficult.

I suspect many of the beneficiaries of this kind of system are not at the
top of the smartphone-savvy list, but it seems that everybody has a
tablet these days, even the old codgers like me!

Thanks

[Trevor]

On 3/03/2016 2:40 PM, Jason wrote:
On Wed, 2 Mar 2016 20:15:52 -0500 "Mike Duffy"
wrote in article
Put a streaming audio server onto your WiFi subnet.


We could do both. The library has excellent WiFi. Adding a streamer
wouldn't be difficult.

I suspect many of the beneficiaries of this kind of system are not at the
top of the smartphone-savvy list, but it seems that everybody has a
tablet these days, even the old codgers like me!

Me too, but rarely carry it around with me. (more people are more likely
to have a smart phone on them than a tablet IMO, even older people)
Those who need hearing aids usually have them with them however.

Trevor.

[geoff]

On 3/03/2016 5:59 PM, Trevor wrote:
On 3/03/2016 2:40 PM, Jason wrote:
On Wed, 2 Mar 2016 20:15:52 -0500 "Mike Duffy"
wrote in article
Put a streaming audio server onto your WiFi subnet.


We could do both. The library has excellent WiFi. Adding a streamer
wouldn't be difficult.

I suspect many of the beneficiaries of this kind of system are not at the
top of the smartphone-savvy list, but it seems that everybody has a
tablet these days, even the old codgers like me!

Me too, but rarely carry it around with me. (more people are more likely
to have a smart phone on them than a tablet IMO, even older people)
Those who need hearing aids usually have them with them however.

Trevor.

When I see people wandering around cradling their tablets I immediately
think "dicks".

geoff

[JackA]

On Wednesday, March 2, 2016 at 10:26:59 PM UTC-5, Trevor wrote:
On 3/03/2016 7:16 AM, Mike Rivers wrote:
On 3/2/2016 2:25 PM, Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

I'm not an authority on this, but it's been my impression for the past
few years that induction loop "T-coil compatible" systems are on the way
out. What seems to be on the way in are short range WiFi based systems
that people can listen to with their smart-ish phones. These systems are
starting to show up in sports bars with a couple of dozen TV sets on
each wall, allowing the patrons to "tune in" to any channel that they
want to watch.

It's probably worth asking the patrons, particularly if it's a small
community, what capabilities they currently have for assisted hearing
now, and if they have WiFi phones or tablets that work with their
hearing condition. Hearing aids are very different these days than they
were 50, or even 20 years ago. I don't know if these new digital in-ear
hearing aids even have induction loop capability.

Not all hearing aid wearers can afford new aids every few years to keep
up with the latest trends, and many older people are not interested in
Hi Tech solutions anyway. T-coil is still very common inclusion on most
aids, even if they have blu-tooth, wi-fi, or any other capabilities.
The mandated standard here is still inductive loop systems, and any
thing else would be additional, not an alternative. That *may* change
one day of course.

Trevor.

This claims, if you purchase a hearing aid, be sure it includes Bluetooth....

https://loopwisconsin.wordpress.com/...il-technology/

Jack

[JackA]

On Wednesday, March 2, 2016 at 8:04:26 PM UTC-5, Scott Dorsey wrote:
Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

Does someone in this august crowd have experience with such
systems? Recommendations? Potential pitfalls?

I have set them up, and they aren't difficult if you follow the rules.
They are less and less popular these days but they are still pretty
commonly installed at big events.

I believe there is good information in the Yamaha Sound Reinforcement
book on laying them out. The secret is to lay the wires out so that
you get even field across the room without hot spots and cold spots
in too many places.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

No one even mentioned the FCC mandate!!!...
http://www.tecear.com/Turn-On-To-T-coil.htm

Jack

[JackA]

On Thursday, March 3, 2016 at 9:06:04 AM UTC-5, JackA wrote:
On Wednesday, March 2, 2016 at 10:26:59 PM UTC-5, Trevor wrote:
On 3/03/2016 7:16 AM, Mike Rivers wrote:
On 3/2/2016 2:25 PM, Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

I'm not an authority on this, but it's been my impression for the past
few years that induction loop "T-coil compatible" systems are on the way
out. What seems to be on the way in are short range WiFi based systems
that people can listen to with their smart-ish phones. These systems are
starting to show up in sports bars with a couple of dozen TV sets on
each wall, allowing the patrons to "tune in" to any channel that they
want to watch.

It's probably worth asking the patrons, particularly if it's a small
community, what capabilities they currently have for assisted hearing
now, and if they have WiFi phones or tablets that work with their
hearing condition. Hearing aids are very different these days than they
were 50, or even 20 years ago. I don't know if these new digital in-ear
hearing aids even have induction loop capability.

Not all hearing aid wearers can afford new aids every few years to keep
up with the latest trends, and many older people are not interested in
Hi Tech solutions anyway. T-coil is still very common inclusion on most
aids, even if they have blu-tooth, wi-fi, or any other capabilities.
The mandated standard here is still inductive loop systems, and any
thing else would be additional, not an alternative. That *may* change
one day of course.

Trevor.

This claims, if you purchase a hearing aid, be sure it includes Bluetooth....

https://loopwisconsin.wordpress.com/...il-technology/

Jack

Wrong link Geoff!...

http://www.tecear.com/Turn-On-To-T-coil.htm

Jack

[Ty Ford]

On Wednesday, March 2, 2016 at 2:25:44 PM UTC-5, Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

Does someone in this august crowd have experience with such
systems? Recommendations? Potential pitfalls?

Thanks,
Jason

Hello Jason,

Loops are still quite relevant. I have a contact, Fred Palm, with whom I've worked on many occasions. He designs such systems and has the hardwoods and knowledge to make sure they work correctly.

I have one of his loop amps here and have set it up here and on several other locations. If installed properly, it's a great and has no latency. If you have people presenting where lips can be seen, wi-fi and BlueTooth can be off-putting.

Please reach out to Fred directly (419) 340-8903 in Toledo, OH or

Please mention that you were in contact with me.

Regards,

Ty Ford

[[email protected]]

On Thursday, March 3, 2016 at 9:50:09 AM UTC-5, Ty Ford wrote:
On Wednesday, March 2, 2016 at 2:25:44 PM UTC-5, Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.



if you are doing a renovation, at least consider having the loop wires installed.

It is much easier to install the wire loop during renovation compared to after the fact.

Mark

[jason]

On Thu, 3 Mar 2016 08:33:46 -0800 (PST) "
wrote in article 40cc6282-c1c6-4627-8dae-

if you are doing a renovation, at least consider having the loop wires installed.

It is much easier to install the wire loop during renovation compared to after the fact.

Mark



That's the plan, since the floor is being replaced too. Most
installations I've read about place the loop(s) at floor level, but I
suppose running it/them around the ceiling would work too.(?)

[jason]

On Thu, 3 Mar 2016 06:50:05 -0800 (PST) "Ty Ford"
wrote in article

Please reach out to Fred directly (419) 340-8903 in Toledo, OH or

Please mention that you were in contact with me.

Regards,

Ty Ford



Thanks, Ty! Will do.

Jason

[Scott Dorsey]

wrote:
On Thursday, March 3, 2016 at 9:50:09 AM UTC-5, Ty Ford wrote:
On Wednesday, March 2, 2016 at 2:25:44 PM UTC-5, Jason wrote:
I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

if you are doing a renovation, at least consider having the loop wires installed.

It is much easier to install the wire loop during renovation compared to after the fact.

Absolutely. Although I have worked with plenty of temporary installs in
convention halls where THHN wire was just taped to the floor.

In a first floor room with wooden construction and basement access, it can be
possible to just run the wire under the floor. Tack it down, add a series
resistor and hook the old Crown D-60 up to it.

The hard problem with these systems is mostly keeping the noise from lighting
dimmers down.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[jason]

On 3 Mar 2016 13:28:55 -0500 "Scott Dorsey" wrote in
article
In a first floor room with wooden construction and basement access, it can be
possible to just run the wire under the floor. Tack it down, add a series
resistor and hook the old Crown D-60 up to it.

The hard problem with these systems is mostly keeping the noise from lighting
dimmers down.
--scott
--


The floor is a concrete slab. It's has carpet now but that will change to
a laminate. It might be easier to run it around the edges of the ceiling.
The room is 25x50. Is that one loop or more?

Dimmers may be a problem, but so may be the "flourescent light" tubes
that are now LED's.

Jason

[Scott Dorsey]

Jason wrote:
The floor is a concrete slab. It's has carpet now but that will change to
a laminate. It might be easier to run it around the edges of the ceiling.
The room is 25x50. Is that one loop or more?

I don't know, my guess is multiple loops but check the Yamaha book. You
can also go out there with a CD player and some wire and just tape a
temporary arrangement out. Borrow a "fox" wire finder from your telecom
guy and wander around the room making sure the sound coverage is even.
When you like what you have, draw it out and have the floor guys install
the wire between the laminate and subfloor.

Dimmers may be a problem, but so may be the "flourescent light" tubes
that are now LED's.

The fox is a good tool for tracking that down also.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[[email protected]]

On Friday, March 4, 2016 at 10:52:45 AM UTC-5, Scott Dorsey wrote:
Jason wrote:
The floor is a concrete slab. It's has carpet now but that will change to
a laminate. It might be easier to run it around the edges of the ceiling.
The room is 25x50. Is that one loop or more?

I don't know, my guess is multiple loops but check the Yamaha book. You
can also go out there with a CD player and some wire and just tape a
temporary arrangement out. Borrow a "fox" wire finder from your telecom
guy and wander around the room making sure the sound coverage is even.
When you like what you have, draw it out and have the floor guys install
the wire between the laminate and subfloor.

Dimmers may be a problem, but so may be the "flourescent light" tubes
that are now LED's.

The fox is a good tool for tracking that down also.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

this is interesting,

you might think that if the wire loop is around the outside of the room
and the room is very large, that the field in the center of the room might be
reduced becasue you are far away from the wire..

but this is not so

http://hyperphysics.phy-astr.gsu.edu...ic/curloo.html


the field will be strong within the circumference of the loop no matter how large the loop may be.. in fact it is strongest in the center.

So it is a matter of Amp turns and every spot inside the loop will have good signal.

interesting

Mark

[Don Pearce[_3_]]

On Fri, 4 Mar 2016 09:13:58 -0800 (PST), wrote:

On Friday, March 4, 2016 at 10:52:45 AM UTC-5, Scott Dorsey wrote:
Jason wrote:
The floor is a concrete slab. It's has carpet now but that will change to
a laminate. It might be easier to run it around the edges of the ceiling.
The room is 25x50. Is that one loop or more?

I don't know, my guess is multiple loops but check the Yamaha book. You
can also go out there with a CD player and some wire and just tape a
temporary arrangement out. Borrow a "fox" wire finder from your telecom
guy and wander around the room making sure the sound coverage is even.
When you like what you have, draw it out and have the floor guys install
the wire between the laminate and subfloor.

Dimmers may be a problem, but so may be the "flourescent light" tubes
that are now LED's.

The fox is a good tool for tracking that down also.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

this is interesting,

you might think that if the wire loop is around the outside of the room
and the room is very large, that the field in the center of the room might be
reduced becasue you are far away from the wire..

but this is not so

http://hyperphysics.phy-astr.gsu.edu...ic/curloo.html


the field will be strong within the circumference of the loop no matter how large the loop may be.. in fact it is strongest in the center.

So it is a matter of Amp turns and every spot inside the loop will have good signal.

interesting

Mark

The only real problem with the magloop is that of orientation. The
receiving coil needs to aligned at least approximately the same way as
the transmitter - ie horizontally. You still get a reasonable signal
if they are off, but once you get close to a right angle the nulling
can be pretty severe.

Probably best not to lie flat on the floor while you listen.

d

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[Scott Dorsey]

wrote:
you might think that if the wire loop is around the outside of the room
and the room is very large, that the field in the center of the room might be
reduced becasue you are far away from the wire..

but this is not so

http://hyperphysics.phy-astr.gsu.edu...ic/curloo.html

Right. If you have a big rectangular room, one loop is the way to go and
if you have multiple loops you have issues at the edges where they interact.

The problems all start when you get places that aren't rectangular, like
cruciform churches.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Don Pearce[_3_]]

On 4 Mar 2016 13:50:50 -0500, (Scott Dorsey) wrote:

wrote:
you might think that if the wire loop is around the outside of the room
and the room is very large, that the field in the center of the room might be
reduced becasue you are far away from the wire..

but this is not so

http://hyperphysics.phy-astr.gsu.edu...ic/curloo.html

Right. If you have a big rectangular room, one loop is the way to go and
if you have multiple loops you have issues at the edges where they interact.

The problems all start when you get places that aren't rectangular, like
cruciform churches.
--scott

You can still route the loop around the periphery, and have the
advantage that everywhere inside is a little closer to the wire than
it might be otherwise. The field in the centre of the room is more or
less uniform, rising sharply as you approach the loop itself. The
actual level of the field is inversely proportional to the average
diameter of the loop.

A good thing about loops is that once you move outside them, the field
dies away very quickly to zero.

d

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[Phil Allison[_4_]]

Jason wrote:



The floor is a concrete slab. It's has carpet now but that will change to
a laminate. It might be easier to run it around the edges of the ceiling.
The room is 25x50. Is that one loop or more?



** Google turns up plenty of good info on loop installation and amplifiers.

Ideally you need an amplifier made for the job with "constant current" output and built in compressor with at least 30dB range.

Alternatively, fitting an 8 ohm resistor with say 50W power rating in series with the loop will also do nicely plus using an external compressor. Hearing aid T pickups operate over an limited dynamic range so the level needs to be kept close to the optimum all the time.

For a room your size, a 50 to 100 watts ought to be enough and the loop can be at floor, wall or ceiling height. The loop should be made from wire with a 1 sq mm cross section or maybe Cat5 with all the strands wired in parallel.



Dimmers may be a problem, but so may be the "flourescent light" tubes
that are now LED's.


** Really doubt LED lights will present any problem - the internal DC power supplies operate at frequencies too high to be heard.


..... Phil

[jason]

On Fri, 4 Mar 2016 16:49:43 -0800 (PST) "Phil Allison" pallison49
@gmail.com wrote in article e5c354b3-43e8-400c-a3f3-

or maybe Cat5 with all the strands wired in parallel.



That's a cool idea! The library basement has a carton with a couple of
miles of discarded Cat5...

[Ty Ford]

On Thursday, March 3, 2016 at 12:53:03 PM UTC-5, Jason wrote:
On Thu, 3 Mar 2016 08:33:46 -0800 (PST) "
wrote in article 40cc6282-c1c6-4627-8dae-

if you are doing a renovation, at least consider having the loop wires installed.

It is much easier to install the wire loop during renovation compared to after the fact.

Mark



That's the plan, since the floor is being replaced too. Most
installations I've read about place the loop(s) at floor level, but I
suppose running it/them around the ceiling would work too.(?)

No. People and their t-colis aren't in the ceiling. They are usually sitting.

[Ty Ford]

On Thursday, March 3, 2016 at 9:45:26 PM UTC-5, Jason wrote:
On 3 Mar 2016 13:28:55 -0500 "Scott Dorsey" wrote in
article
In a first floor room with wooden construction and basement access, it can be
possible to just run the wire under the floor. Tack it down, add a series
resistor and hook the old Crown D-60 up to it.

The hard problem with these systems is mostly keeping the noise from lighting
dimmers down.
--scott
--


The floor is a concrete slab. It's has carpet now but that will change to
a laminate. It might be easier to run it around the edges of the ceiling.
The room is 25x50. Is that one loop or more?

Dimmers may be a problem, but so may be the "flourescent light" tubes
that are now LED's.

Jason

1. If there's rebar in the floor, you have to account for that.
2. 25 x 50 is way too big for complete coverage with one wire going around the wall.

There's hard science on this install stuff, you really need to pay attention to details.

[Ty Ford]

On Friday, March 4, 2016 at 12:14:05 PM UTC-5, wrote:
On Friday, March 4, 2016 at 10:52:45 AM UTC-5, Scott Dorsey wrote:
Jason wrote:
The floor is a concrete slab. It's has carpet now but that will change to
a laminate. It might be easier to run it around the edges of the ceiling.
The room is 25x50. Is that one loop or more?

I don't know, my guess is multiple loops but check the Yamaha book. You
can also go out there with a CD player and some wire and just tape a
temporary arrangement out. Borrow a "fox" wire finder from your telecom
guy and wander around the room making sure the sound coverage is even.
When you like what you have, draw it out and have the floor guys install
the wire between the laminate and subfloor.

Dimmers may be a problem, but so may be the "flourescent light" tubes
that are now LED's.

The fox is a good tool for tracking that down also.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

this is interesting,

you might think that if the wire loop is around the outside of the room
and the room is very large, that the field in the center of the room might be
reduced becasue you are far away from the wire..

but this is not so

http://hyperphysics.phy-astr.gsu.edu...ic/curloo.html


the field will be strong within the circumference of the loop no matter how large the loop may be.. in fact it is strongest in the center.

So it is a matter of Amp turns and every spot inside the loop will have good signal.

interesting

Mark

Damn! NO! The signal only radiates from a wire so far.

[Ty Ford]

On Friday, March 4, 2016 at 7:49:49 PM UTC-5, Phil Allison wrote:
Jason wrote:



The floor is a concrete slab. It's has carpet now but that will change to
a laminate. It might be easier to run it around the edges of the ceiling.
The room is 25x50. Is that one loop or more?



** Google turns up plenty of good info on loop installation and amplifiers.

Ideally you need an amplifier made for the job with "constant current" output and built in compressor with at least 30dB range.

Alternatively, fitting an 8 ohm resistor with say 50W power rating in series with the loop will also do nicely plus using an external compressor. Hearing aid T pickups operate over an limited dynamic range so the level needs to be kept close to the optimum all the time.

For a room your size, a 50 to 100 watts ought to be enough and the loop can be at floor, wall or ceiling height. The loop should be made from wire with a 1 sq mm cross section or maybe Cat5 with all the strands wired in parallel.



Dimmers may be a problem, but so may be the "flourescent light" tubes
that are now LED's.


** Really doubt LED lights will present any problem - the internal DC power supplies operate at frequencies too high to be heard.


.... Phil

Multiple strands has been found not to work as well as one strand. Think, phase distortion.

[Phil Allison[_4_]]

Jason wrote:

I'm a trustee of our local library. The Community Room
is about to undergo renovation. One consideration brought
up by many library patrons is inclusion of an inductive "hearing
loop" for folks with hearing aids. The room hosts lectures and
movies and occasional small-scale live music.

Does someone in this august crowd have experience with such
systems? Recommendations? Potential pitfalls?


** When there is a lecture and the speaker wishes to use a microphone linked to the loop amplifier - make sure it is a condenser type. Dynamics will pick up the radiated field from the loop and this can cause nasty feedback.


.... Phil

[Phil Allison[_4_]]

Ty Ford wrote:




For a room your size, a 50 to 100 watts ought to be enough and the
loop can be at floor, wall or ceiling height. The loop should be
made from wire with a 1 sq mm cross section or maybe Cat5 with all
the strands wired in parallel.


Multiple strands has been found not to work as well as one strand.
Think, phase distortion.


** Nah - I'm not gonna do that.

Too silly for words.


.... Phil

[jason]

On Sat, 5 Mar 2016 18:25:18 -0800 (PST) "Phil Allison" pallison49
@gmail.com wrote in article 34f607cd-1d32-49d1-bd17-

Dynamics will pick up the radiated field from the loop and this can cause nasty feedback.

That makes sense. Thanks.

[Jason[_15_]]

In article , says...
I believe there is good information in the Yamaha Sound Reinforcement
book on laying them out.


Strange. I dug out the Yamaha book, says it's the second edition. There
is an index entry for inductive loops, but on p 171 there is NOTHING
about them - it's about mixers. And there's nothing in the table of
contents. I wonder if something fell through the cracks when they did
the second edition...

[Scott Dorsey]

Jason wrote:
On Fri, 4 Mar 2016 16:49:43 -0800 (PST) "Phil Allison" pallison49
wrote in article e5c354b3-43e8-400c-a3f3-

or maybe Cat5 with all the strands wired in parallel.


That's a cool idea! The library basement has a carton with a couple of
miles of discarded Cat5...

If you do this, you have the choice of having multiple paralleled loops,
or just one big loop with all the lines in parallel. Which one is a win
probably depends on the size of your loop.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Jason wrote:
On Sat, 5 Mar 2016 18:25:18 -0800 (PST) "Phil Allison" pallison49
wrote in article 34f607cd-1d32-49d1-bd17-

Dynamics will pick up the radiated field from the loop and this can cause nasty feedback.

That makes sense. Thanks.

The real solution for this is to keep the microphones out of the loop. This
is easy if you have a well-defined stage area and audience area, but I can
see instances where it could be an issue.

The flux drops off very fast once you get out of the loop.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Phil Allison[_4_]]

Scott Dorsey wrote:


or maybe Cat5 with all the strands wired in parallel.


That's a cool idea! The library basement has a carton with a couple of
miles of discarded Cat5...

If you do this, you have the choice of having multiple paralleled loops,
or just one big loop with all the lines in parallel. Which one is a win
probably depends on the size of your loop.


** With all 8 conductors in parallel, the loop impedance is about 1 ohm for 50 metres. With all in series, it rises to over 50 ohms.

A 100W/8ohm amp will deliver about 1 amp peak into such a loop and might not be enough - despite the extra field strength from having more turns.

Commercial loop amplifiers normally specify a loop of less than 2 ohms so the "constant current " feature works properly.


..... Phil