The Mid-Field Concourse (MFC) is a new building which adds 30 gates to Hong Kong International Airport (HKIA). Initiated by the Hong Kong Airport Authority, the MFC is a key component of the airport’s expansion plans, which include the opening of a third runway and Terminal.
In 2011, acoustics and AV consultant Arup Hong Kong started the process of defining a future-proof strategy and design for the MFC’s public address capability, looking at all acoustic, technological and electro-acoustic approaches. Leading the project, Henry Chan for Arup HK was looking for a system with matrixed zone grid, capable of relaying different messages and signals to different zones, through automated and live playback and emergency situations.
With Cobranet infrastructure to handle the signal traffic, different messaging functions had to have distinct sound and acoustical performances, identifying, for example, live announcements in the Gates zone, or emergency announcements in the Fire zones, with seamless coverage across the entire terminal for General PA. Last but not least, the acoustic control of the PA design had to minimize any need for acoustic treatment, maintaining the aesthetic and architectural style of HKIA’s Terminal one.
Over 3 years, working closely to support Arup and the Airport Authority, NEXO engineers brought a design to life, providing acoustic and electronic simulations, live demonstrations and value engineering. The final validated design, a low-impedance system using NEXO’s GEO S8 ultra-compact tangent array loudspeaker modules and NXAMP controllers, went out to tender in 2013, and the installation contract was awarded to PCCW in Hong Kong, working in conjunction with Top Plot International Limited, distributor of NEXO products in China.
Nearly 200 line-source loudspeaker cabinets were used for the MFC project, each of which had to be concealed within a giant suspended ceiling of asymmetrical design. The exact angle and tilt of each cluster of GEO S805 and S830 modules had to be calculated. To do this for over 100 clusters, working inside an airport ceiling, amounted to nearly six months of installation work for PCCW.
The positioning and spacing of loudspeakers has been calculated so that listeners close to the speakers, and others further away in the atrium space, would receive the same SPL. Moving on the travellators, airport users experience a seamless sound field along the centre line with great separation within each side. Live announcements at the gates are made in clearly focused sound with natural vocal presence, while general PA messages are audible as a background system.
The entire system has been programmed through NEXO’s proprietary Remote ESMonitor Control software, which manages all the NXAMP controller-amplifiers on the EtherSound network. Preliminary tests of the STI (measuring speech intelligibility) revealed between results between 0.62 to 0.7, well above the target of 0.55.
NEXO has provided deep and wide-ranging technical support for the HKIA project, from concept stages involved Nicolas Kirsch of NEXO Asia and François Deffarges and David Hochstenbach of the Engineering Support Team in Paris, to on-site design input and back-up from Leo Ho of NEXO Asia.
Setting a new standard for the sound quality in airport terminals, the MFC installation is a blueprint for the future. “We have clearly achieved excellent results, after many years of dedicated work and detailed design, and trust in the consultants’ and designers’ approach, “says Steven Tam, project manager for the Airport Authority. “We have totally reached our goal to create a sound quality way above Terminal 1 and 2. A new standard is established and this is probably the best-sound airport terminal in the world.”
