When the decision was made to reinstate announcements at Waverton Station a few kilometres north of the Sydney CBD, fury from local residents resonated more than the local commuter trains hurtling northwards to Hornsby.
“Locals are horrified as it would mean up to 2000 announcements per day,” a spokesman commented.
Following a deal struck with transport authorities in 2010, the locals were spared regular announcements at a station where trains commonly stop every two minutes.
Having perfected a bespoke audio-over-IP solution for some 300 plus stations within the Sydney Trains and NSW TrainLink network, tm stagetec systems was challenged to solve the local issues at Waverton. The new digital announcement system needed to ensure travellers were in the know, whilst letting residents go about their lives oblivious to the fact that the 8.11 to Parramatta was about to depart platform one.
tm stagetec systems MD, Treva Head, said, “Previous tenders for our digital PA centred around required speech intelligibility for passengers.
“However, Waverton required a much more sensitive approach and as such the emphasis was placed more on environmental pollution control of the Digital Voice Announcements (DVA), including ambient noise control, directional speaker design and time of day switching.”
Based on standard TCP/IP protocols with extremely low latency, Waverton is controlled and monitored from the Central Network Management System (CNMS) via the IP network. The centralisation of voice-based announcements adopts a node-based design that minimises the installation of on-site equipment. The central management system has nodes comprising one or more MF4 matrix frames and under each node the stations fall. Currently, there are around 20 nodes each handling approximately 20-60 stations each.
Originally opened in 1893 as Bay Road and renamed as Waverton in 1929, a scalable cut and paste PA design could not be applied at this heritage-listed station. As is the norm, the DVAs are made in full bandwidth in real time with less than 2ms delay to the end of the two platforms.
The analogue audio signals are firstly routed to a digital PA MF4 TDM communications router, before entering a switch over a Layer 2 network and a Dante Enabled Network Amplifier Module or NAM. Each NAM can drive up to four 12W speakers, for which loudspeaker processing can be configured differently according to the station’s bespoke requirements.
Also available as an indoor version, the IP66-rated sealed NAM models installed at Waverton can not only operate in extremely wet conditions, they can also fully function in direct sunlight by dissipating internal heat.
Ambient AKG microphones on both station platforms feed back up to the node incorporating the audio processing. When the PA is in operation, the adoption of echo cancellation algorithms ensures that the microphone picks up the PA, cancels it out of the microphone and provides pure ambient noise.
The same system provides for auto-mixing when ambient noise levels rise and the announcements need to increase their levels louder, for example when a train arrives.
“When a train comes in, we can smoothly increase the volume of the announcement in real time, then turn it back down again when the train leaves,” Mr Head said.
“The same can be done if there are lots of people on the platform, but you don’t really notice it unless you are actually there.”
While the audio levels of the announcements have been reduced – particularly in the evenings – minimised and relevantly zoned, careful attention has also been applied to the loudspeaker directivity.
Standardised weatherised TOA CS154Q 8 Ohm horn models with FIR filtering firing towards the track under the platform roofing constitute the majority of the speakers. However, the long, curved platforms required a more specialised loudspeaker solution in compliance with both the 2ms delay and restrictive dB spillage.
Facing down the platform, two weatherproof EDC Acoustics SC-30 loudspeakers have been installed under the canopy end of each roof to cover the 150m distance down the full length of the platform. The plane array loudspeaker design comes with a unique scaling feature.
Its selection at Waverton is fully warranted as the two-dimensional arrays act as a single acoustic point source with variable horizontal and vertical pattern control, whilst providing coherent summation across the entire audio bandwidth. Specialised algorithms provide full bandwidth power to the three four-inch LF woofers and 27 LF drivers that are individually powered by 200W and 30W amplifiers respectively.
tm stagetec systems engineers worked closely with Sydney Trains Audio Services Manager, Charles Chan, and the electro acoustic engineer David Connor to configure the two dimensional arrays of each plane array speaker within the DSP programming software.
Also configurable within the Dante domain, a Williams Sound DL207 SYS D induction loop system has been installed into both platforms to provide assistive listening capabilities on each platform. Incorporating DSP audio processing, audio override and a pink noise generator, this loop system also provides an option for either local or PC app configuration.
Although the majority of announcements originate from the centralised DVA, local live announcements can be made from either a paging panel microphone or a smartphone via a downloaded VCOM app.
“Should a speaker fail or need replacing, a new model can be installed in its’ place without needing to re-calculate the DSP settings as they are already stored in the CNMS,” Mr Head said.
Chris Walsh, Deputy Executive Director of Customer Area for Sydney Trains, said, “‘For almost ten years, there were no announcements for passengers using Waverton Station.
“This had become a bit of an issue for our customers. We’ve worked very closely with the local community to come up with positive outcome for everyone. The adoption of a digital speaker system provides directionality, minimises noise spillage and zones non-urgent announcements.”
This partner content is brought to you by tm stagetec systems. For more information, visit www.tm-systems.com.au.
Published with kind permission of Pro AVL Asia.