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Special report: An audible change in assistive technology

With more people of all ages experiencing problems with their hearing, awareness of the benefits of assistive listening systems is growing. Installation looks at the main technologies and where this crucial market might be heading

In life we have a moral imperative to treat everyone the same, regardless of gender, race, religion, sexuality or any other aspect of personal identity. We know diversity is important, yet a lack of inclusion continues to hinder our workforces – even in AV. The world of AV moves fast – just look at the pace of change since the start of the pandemic! – so, in terms of diversity in the workplace, just how far behind are we?

As far as most people are concerned, hearing loss is something experienced by those with congenital conditions, severe illness or who are just getting older. But increasingly it is a problem among the younger generation. The World Health Organisation (WHO) reports that over 1 billion young adults are now at risk of permanent, avoidable hearing loss due to unsafe listening practices. WHO also projects that by 2050 nearly 2.5 billion people will have some degree of hearing loss, with at least 700 million of those requiring what it describes as “hearing rehabilitation”.

Of the terms used in this field, ‘hearing loss’ is applied to those who do not hear as well as someone with normal hearing (that is, with hearing thresholds of 20dB or better in both ears). ‘Hard of hearing’ covers people with mild to severe hearing loss, who often use a hearing aid, cochlea implants or other form of assistive device. ‘Deaf’ describes profound hearing loss, with very little or no hearing.

In recent years, hearing aid technology has improved considerably, with higher sensitivity and a greater degree of miniaturisation. Despite this, they still need to be augmented in public places and for events such as concerts and conferences by being connected to assistive listening systems (ALSs). The best established of these is the induction loop, also known as hearing loops or audio frequency loop systems (AFILS). These are now widely available in public areas, including theatres, churches, cinemas and some shops.

The loop itself is usually made from a single turn of cable or wire installed round the designated operating area. A magnetic field is generated as current passes through the loop; in conjunction with a specialist amplifier, this is able to reproduce any audio signals picked up by specially placed microphones or an interconnected sound system.

Hearing aid wearers can pick up the output of the induction loop by switching their aids to the T (tele-coil) setting, as can those with suitably equipped smartphones. Given the ubiquity of smartphones, this was a necessary addition, particularly with the increase in hearing loss among younger age groups. “Aging is a big factor in hearing loss,” comments Jesal Vishnuram, technology advisor to the RNID (Royal National Institute for the Deaf). “But research is showing that the problem is accelerating among young people, who are listening to music on their smartphones at levels of up to 110dB, depending on the headphones.”

Vishnuram explains that tele-coil and loop systems were originally designed for landline telephones and are old analogue technology. “Induction loops are also expensive to install and maintain,” she adds. Despite that, loop systems are probably still the most widely available form of ALS. The International Hearing Loop Manufacturers Association (IHLMA) claims that hearing loops and T-coils are “still the only technology that meet all the needs of hearing aid users, including intelligibility, discretion, ease of use, transient use and availability”.

The induction loop market is small and niche but mature, with the best-known amplifier manufacturers including Contacta, SigNET and Ampetronic. In 2020 Ampetronic entered into a strategic partnership with US ALS specialist Williams AV to market both brands across Europe. Williams, like other manufacturers, also works with both proven and emerging enabling technologies. The two main challengers to induction loops over the last 20 to 30 years are FM/DM (frequency modulation/digital modulation) and infrared (IR).

Alternatively called radio frequency assistive listening systems, FM/DM systems are based on sending low frequency radio signals from a source such as a microphone or audio system to FM receivers. The receiver can be a dedicated unit that is distributed to people attending a meeting, church service or who are part of a tour group. Hearing aids and cochlea T-coil couplers can also pick up the signals through a personal inductive neck loop. While these wireless systems are relatively easy to install and have a range of around 153 metres, with the ability to be used outside, downsides include having to supply receivers for all users, regular battery replacement, variable frequency range and the need for licences on some equipment.

In IR set-ups, feeds from the sound source are sent to a transmitter and modulator. From there signals are transmitted wirelessly into areas saturated with IR light and picked up in the same way as FM/DM. Advantages include a simple installation process, a high level of security because the signals cannot pass through walls and multi-channel capability (also offered by FM/DM). Among the disadvantages are that IR is line of sight and cannot be used in direct sunlight.

The ALS sector is now looking beyond the legacy technologies, partly because of their respective limitations and partly due to what new alternatives can offer. Jesal Vishnuram comments that smartphone developers in particular are keen to move away from induction loops, largely because T-coils take up valuable space on handsets. The preferred replacement for many manufacturers, she says, is Bluetooth Low Energy (BLE). This is a wireless personal area network technology designed by the Bluetooth Special Interest Group for defined market sectors such as healthcare, fitness, security and home entertainment.

Among the earliest implementations of BLE for ALS was a hearing device for the Apple iPhone that appeared ten years ago. This, Vishnuram says, used a lot less audio power than other systems and has led to further developments that are now coming to fruition. “Companies like Samsung and Apple have been looking at dual audio sharing, with the next stage being connecting to an unlimited number of devices,” she comments. “It will take time to implement and right now people are looking into how it will all work together. It has been designed for hearing aids but it has to go through a device like a smartphone and you need to know what it is connecting to. But it should be easier than loop systems.”

One of the manufacturers working with BLE is Bellman & Symfon, which produces personal amplifiers and listening systems. UK account manager Simon Haisman observes that Bluetooth “seems to be the most robust and widest used technology” for ALS. “It is the technology available to us right now,” he says. “There are probably only about 10 million people in the UK that are deaf or hard of hearing and many will not do anything about it. We are looking at a small target audience so we have to make sure the technology is affordable.”

WiFi is also widely available and familiar to most people. As such it is regarded as a potential replacement for induction loops but Haisman says although Bellman & Symfon did look at WiFi, it has “gone down the Bluetooth route”. A company that has opted for WiFi is Sennheiser, which in 2014 introduced MobileConnect. This is described as an assistive and personal listening system that streams live audio over WiFi to any iOS or Android smartphone in a designated area.

MobileConnect comprises three components: an “audio-to-network bridge” called MobileConnect Station, which takes audio signals in a room and streams them to any preferred streaming network; the MobileConnect receiver app; and the MobileConnect Manager for handling multiple Stations. It is able to operate with existing WiFi access points and can feed up to 100 smartphones from a single Station.

Kim Franklin, vice president of marketing, Listen Technologies, says that newer technologies such as Wi-Fi and BLE are quickly becoming a preferred choice for assistive listening because of simple venue installation and intuitive user interface. “Wi-Fi systems provide a discreet experience for end users since they can use their own smartphone or checkout a smartphone receiver provided by the venue,” she says. “Wi-Fi systems work on the venue’s network and cost less than traditional assistive listening systems. BLE will also become a viable option for assistive listening technology with the current focus on innovation in the Bluetooth space. Future solutions will support various personal assistive listening applications in multiple markets.”

Jakub Kolacz, manager for product and commercialisation at Sennheiser Streaming Technologies, sees the benefits of WiFi as both its transmission capabilities and the opportunity to work on a BYOD (bring your own device) basis. “The fundamental requirement for somebody with a hearing impairment is amplification,” he says. “Our system can go direct into a hearing aid or cochlea implant and enables people to focus more on what they are hearing.” He adds that in big buildings it can be difficult for a hard of hearing person to detect the different noises coming into their ear or hearing aid. To deal with this, MobileConnect has a Personal Hearing Assistant feature that allows people to enhance speech intelligibility and sound quality.

Kolacz also comments that the smaller size of modern hearing aids and the interconnectivity with smartphones is attractive to young people with hearing difficulties because it reduces the perceived stigma of being seen to use assistive devices. “The younger generation will get used to hearing amplification,” he says. “If someone has grown up with [smartphone] technology it is more natural for them to rely on amplification if they need it. Headphones also offer some functionality and assistance, particularly if they have transparency mode.”

While Kolacz says WiFi has improved considerably in recent years, with greater stability and lower latency in the region of 50 milliseconds, the RNID’s Jesal Vishnuram observes that there can still be the problem of lag if a large number of connected devices is being used on a network at the same time.

While the technical pros and cons of Bluetooth and WiFi for ALS can be debated and analysed, it is reassuring that such modern technologies are offering greater accessibility and inclusivity at a time when those are needed in everyday life more than ever before.

Last word goes to Kim Franklin: “We see assistive listening solutions and technologies becoming more widely available as venues work towards enabling more inclusive and immersive experiences for their guests. Technology will continue to evolve to provide seamless experiences for end users and minimal installation for venues, providing a better experience all around.”

Click here to read a report on the culmulative effects of hearing loss by Halvard Eriksen, service manager at B Mikklesen AS.