- Where
can I find out about the Disability Discrimination Act (DDA)?
Visit the Government website click here
Contact your local council's Access Officer
Ask us for help - we have a leaflet available too - Can I use electric guitars with the loop system?
Generally, electric guitars cannot be used within an induction loop system.
The "pick-up" coils on electric guitars will pick up the electromagnetic field from the loop system in tha same way that the "pick-up" (telecoil) in a hearing aid. If the guitar is used with its own "combo" amplifier, the signal from the loop will be picked up by the guitar, and heard through the guitar amplifier's speakers. Worse still, if the guitar sound is fed to the loop system, feedback will occur. Acoustic guitars with "crystal" (eg Barcus Berry) or Electret (eg C-ducer) pickups are not affected. - What
type of microphones can be used with loop systems?
Ideally, phantom powered electret condenser microphones. Dynamic microphones may cause problems because the coil in the microphone will pick up the magnetic field from the loop, possibly causing feedback.
- I
need to fit a hearing aid loop system in a meeting room. There
is no need for a PA system but do I need a microphone?
Yes, loop systems need microphones, but remember that several microphones may be needed so that one is always close to the talker!
- How do I stop my electronic keyboard from picking up the loop signal?
Most modern electronic keyboards are not affected by loop systems, however if "hum loop" if formed by the cables linking the keyboard to an amplifier, the system may pick up the loop signal. Use an active Direct Injection Box, or a good quality passive DI box with a screened transformer. NEVER remove electrical earths from mains powered equipment. They are there for your safety. We also recommend a RCD "powerbreaker" type device should be fitted to ensure the safety of performers.
- How
do I connect several microphones to the loop amplifier?
Microphones need to be close to the talker, so that they pick up mostly the talker, with the minimum other noise or reverberation. If several microphones are "on" then all microphones except the one nearest to the talker pick up background noises or reverberation from the room. If more than 3 microphones are used, an automatic microphone mixer is recommended. This "reduces" the sound from microphones that are not "in use" ensuring the best sound is fed to the loop system
-
Can I use a PA or HiFi amplifier to drive the
loop cable?
No. A specially designed loop amplifier is required. Conventional amplifiers are designed to drive loudspeakers, and are called "voltage amplifiers."
Loop amplifiers are "current amplifiers", designed to give the appropriate current in the loop, even though the impedance of the loop rises with frequency.
- How
many "turns" or cores of wire should I use for the
loop?
We recommend single turn loops, as there are problems associated with multi-turn loop cables due to the high voltages required to produce adequate current at higher frequencies. This is due to the rise in electrical impedance of the loop "coil" which rises with frequency, compounded with the rise in impedance proportional to the square of the number of "turns", (eg. A 2 turn loop will need 4 times the voltage to drive it, while only gaining a factor of 2 in the effective loop current contributing to the magnetic field strength.)
- How
can I have more than one loop system in the same area?
Use an Infra-Red transmission system with personal neck loop receivers. This is useful where adjacent rooms need a loop system or, for a multi-language conference or, when different sound sources are needed in a museum for example. 'Low-spill' loop designs can also be used in adjacent spaces - these require designing in advance of loop cable installation. Size of building, number of users and the environment all need expert consideration - we can advise the most suitable option for your project and budget.
Frequently
Asked Questions about Hearing Aid Loop Systems
(Induction Loop System or sometimes referred
to as Deaf Aid Loop System)
Where
can I find out about the Disability Discrimination Act (DDA)?
Can
I use electric guitars with the loop system?
What
type of microphones can be used with loop systems?
I
need to fit a loop system in a meeting room. There is no need for
a
PA system but do I need a microphone?
How do I stop my electronic keyboard from
picking up the loop signal?
How do I connect several microphones to
the loop amplifier?
Can
I use a PA or HiFi amplifier to drive the loop cable?
How many "turns" or cores of
wire should I use for the loop?
How
can I have more than one loop system in the same area?
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