Choosing the right assistive listening technology will make spaces more accessible to those with hearing impairment, says Andrew Thomas.
03 June 2019 | Andrew Thomas
To loop, or not to loop?
Assistive technology amplifies the desired sound above distracting background noise.
The most familiar solution is the hearing or induction loop:
1. Copper wire is placed beneath the flooring around the perimeter of the space or in a series of loops across a larger area.
2. Sound from a microphone or a PA system is converted into a magnetic signal by an amplifier.
3. The loop transmits this signal to a wearer's hearing aid, which converts it back to sound using its built-in magnetic coupler or 'T-coil'.
Large-area hearing loops can transform the experience of the congregation at a place of worship, delegates in a conference room or passengers in an airport terminal.
Short-range or 'one-to-one' hearing loops enhance communication with staff at a till point or service desk. These can also be integrated into speech transfer systems to make every secure service window accessible to customers with a hearing impediment.
Infrared systems use invisible light to project sound via an IR transmitter. Receivers then convert the light into audio and allow a person to listen clearly with or without hearing aids.
Although these can be used for theatre auditoriums or conference spaces, IR systems have distinct advantages where sound needs to be contained, as in courtrooms or meeting rooms where the spillage of sound into neighbouring spaces has to be avoided.
Radio frequency systems
Radio frequency systems are ideal when sound sources need to be wirelessly transmitted across large areas. They use radio waves so the signal is unaffected by a building's structure or internal fittings.
RF systems' ability to transmit to multiple receivers simultaneously makes them ideal as an assistive listening device for conferences, exhibitions and museums, as well as use in guided tours.
Ensure proper integration
Assistive listening technology should be an inherent part of any development scheme. For example, while a skilled installer can conceal loop cabling in the most challenging spaces (think listed buildings, timber-floored auditoriums) it is far easier and cheaper to incorporate it into a design and make sure it is laid before flooring goes down.
Understanding a building's construction means that audio engineers can calculate the signal loss from a metal substructure or the potential interference from an air conditioning unit.
Accurate room sizes will also affect the selection of transmitters to make sure they are powerful enough to give coverage across the whole space.
Schemes involving open areas such as the concourse on a railway station need careful consideration. Listening points may be planned for hearing aid wearers to stand in to hear announcements, but can they see the information boards at the same time? Is there seating they can use? And is there signage to show them where to stand?
All of these factors demonstrate the need for careful planning to offer the user the best outcome and to prevent costly redesigns further down the line.
Regulations and guidance
Being able to hear clearly is a key factor in employee well-being and public spaces need to be inclusive to meet legal and best practice requirements.
It is important to become familiar with the accessibility requirements as listed in the Equality Act 2010 and part M of the Building Regulations.
Installing assistive listening technology is one thing, but if it isn't performing well when someone tries to use it, it might as well not be there.
A well-planned installation with a continual schedule of maintenance and testing is essential to create an inclusive space that is accessible to all.
Andrew Thomas is market development director at Contacta Systems