Public address: Important announcements

Bosch PA-VA Image
Phnom Penh airport in Cambodia with Bosch PA-VA systems

With the number of airports in APAC increasing, Hurrairah bin Sohail talks with manufacturers about how intelligibility and quality can be ensured for PA-VA systems in these environments.

As Asian markets mature and the standard of living across countries rises, the transport sector has started to boom.

In particular, the number of new airports being built across Asia as well as the traffic volumes they handle is rising.

Joe Andrulis, executive vice president, corporate development for Biamp, provides numbers to back up these claims: “Global air traffic is increasing and Asia accounts for 45% of the world’s top 20 busiest airports and will continue to play a growing role as the number of airports increase. According to the CAPA Centre for Aviation, large Asian airports that handle over 30 million passengers annually and are not constrained by infrastructure are positioned for expansion with the ability to handle 50 million to 60 million passengers annually.”

Andrulis also sheds light on what this growth means for airports: “With expansion comes the need for appropriate AV solutions that are flexible and scalable – from passenger announcements and communications to digital signage integration to voice alarm and emergency notifications. The demand for PA-VA solutions will continue to grow as airports expand and as other airports upgrade to meet the demands of keeping travellers informed and safe.”

Alerting passengers is the core function of PA-VA systems but it is important to remember that in the worst-case scenario they also perform a critical role. Yoshio Furuse, product marketing manager at TOA, cites a recent example: “In September 2018, Typhoon Jebi caused extensive damage to Japan Kansai airport, submerging part of the airport. This brought down the electrical supply to the PA-VA system, paralysing the entire airport. Despite the fact that there were some emergency provisions, like food and fresh water, the airport had no means to make it known to the passengers stranded at the site as announcement and emergency instructions could not be made. It was a chaotic scene at the airport. This disaster taught us the importance of airport PA-VA systems. After this disaster, the PA racks and the main system are now installed at a higher location in order to protect it and avoid encountering the same incident again.”

With the crucial purpose of PA-VA systems in airports beyond debate, it is surprising to find that the audio provided by these systems is not always of the highest quality. Certainly, most travellers have had the experience of being in an airport and not understanding broadcasted audio announcements due to low audio intelligibility.

The problem is hard to unpack as Andrulis from Biamp says: “In complex system designs and audio environments like airports, poor audio quality might be caused by any of a number of sources. Some buildings are inherently more difficult acoustic environments due to structural design or reflective surfaces that create hot and dead spots or a tendency to echo. Poorly designed equipment may not include sufficiently sophisticated processing to adequately correct for even common challenges.”

Eric Zhang, president of CMX Audio, agrees and provides further opinions: “The main reason for failure is the fact that installation and design are not always well matched with architecture. Secondly, these public buildings accommodate different people flows, and this factor or variable is something that the designer and installer are not informed of which makes it hard to account for it. Thus, the PA-VA system for airports must be improved from time to time as more information and data regarding usage becomes available.”

Furuse from TOA brings up further complications that are pertinent to Asia Pacific and show how the goalposts for good audio intelligibility keep shifting: “In Japan [and many other Asian countries], there is the issue of an aging population and being a Japanese company, we have had to develop a set of special quality standards and sound tuning for speech intelligibility targeted at elderly people in Japan. At present it’s only available in the Japanese language but we have started working on it for other languages as we see the demand to cater for a growing aging population worldwide. These types of studies will be important for PA-VA systems in order to create good speech intelligibility in airport environments.”

Daniel Quek, senior manager for regional marketing installed sound at Bosch, says: “Many airports in Asia, and this is based on our experience across the region over the last ten years, do not take the step to appoint an acoustic specialist. The design for the PA-VA system falls to the system integrator. PA-VA for airports is crucial and the right resources must be deployed to ensure that the manufacturer’s products can perform to the best of their ability.”

With multiple moving parts involved in delivering PA-VA systems, the blame for low quality audio cannot be laid at any one party’s feet. Andrulis from Biamp says: “Designing both the building and the equipment in airports might be further constrained by regulations that inadvertently make intelligible audio harder to ensure. Even when buildings and equipment are not the issue, poorly designed or implemented solutions can still result in an unsatisfactory audio experience. It is unfair to point to any one of the participants as the sole culprit. When building excellent communication systems, this community acts like links in a chain and it only takes one or two weak links to cause a project to fail.”

The common thread in our discussions with manufacturers with regards to ensuring quality for PA-VA systems was that all parties involved must work together towards the same goals. Andrulis from Biamp says: “The most productive scenario is where each of the project participants does its job with an understanding and concern for the impact its work has on the acoustic experience. Architects design with audio friendly structures and materials and equipment makers build robust products with modern signal processing to compensate for challenging environments against standards written to facilitate a successful outcome not inhibit it.

“As an equipment maker, Biamp devotes substantial energy and resources to designing sophisticated signal processing algorithms into our products to overcome even the most serious audio issues. Last but not least, consultants and integrators that collaborate to select and commission the mix of system components best matched to the functional requirements of the application and acoustic characteristics of the facility are essential for success.”

According to Zhang from CMX Audio constant engagement holds the key: “Airports must purchase PA-VA systems with comprehensive after-sales service and maintenance service. This is very important. Moreover, the supplier should select the digital signal processor with care and be ready to upgrade it. The proper DSP can enable flexible signal streaming, longer distance transmission and better compatibility with video and Passenger Information Systems.”

A specific technological development that aimed to improve PA-VA systems is the move to IP networks. However, it might not have had the desired effect in full. Quek from Bosch says: “With the emergence of IP based solutions, the quality of PA-VA systems and what they can achieve has improved. But that is not to say that it doesn’t come with its own set of challenges. In order for PA-VA systems to work over IP networks the network infrastructure has to be of a particular standard and this is another quality check that we now have to perform. We also have to now work within the constraints of the IP networks, which means having to contend with issues of latency and quality audio reproduction.”

With so many moving parts, would a ‘single-vendor’ approach or a ‘turnkey-solution’ provider be preferable? After all, becoming a ‘one-stop-shop’ seems to be the goal for many manufacturers in the AV industry nowadays. Andrulis from Biamp says: “Ultimately, system integrators have the final say over the selection of components they integrate into a system on a particular project, whether that be from one or many different equipment vendors.

“Nevertheless, we are seeing a growing trend and preference for single vendor supplied systems where they are available. Buying many components or complete systems from a single vendor that have been expressly designed and tested to function well with one another reduces the likelihood of integration problems and increases overall system performance and reliability. In addition, if a problem does arise, getting vendor support is much easier as the debate over which vendor is responsible for solving a problem is eliminated if only one is involved.”

However, taking on the entire responsibility for PA-VA systems might be easier said than done.

Quek says: “At Bosch, we have a good solution for the audio part be it communication, processing, speakers or amplifiers. But a commonly requested feature by airports is integration with the flight information system. Whether it is a check-in gate announcement or changes to flight departure times, airports are looking to have these announcements made completely automatically when they are registered. This integration is something that is still lacking when it comes to the current range of PA-VA systems on the market today."