Sunday, June 23, 2024

Alcorn McBride: Everyone loves a parade

Technology that makes parades flow through a park with ease

By Scott Harkless, Alcorn McBride

ABOVE: Parades can excite and engage guests in meaningful ways. They can be daily occurrences or special events such as this Chinese New Year parade at Ocean Park Hong Kong in 2012. Photo courtesy Shankar S. via Flickr and Wikimedia Commons

With their elaborate floats, live performers, and engaging soundtracks, parades are often star attractions within theme parks. However, since they operate within the common areas of the park and involve a widely distributed audience, they can also be one of the most technically challenging attractions to build. The best way to avoid having your parade rained on (technologically speaking!) is to understand the key concepts behind how they work and leverage the right tools to overcome the common challenges.

Audience and audio

First, we have to consider the sheer size and location of the audience. Parades usually travel through the heart of the theme park and are one of the most highly anticipated attractions. Dense crowds are inevitable. Although the show experience originates from the parade floats, the crowds make it impractical for the floats to provide all of the show audio. If they did, the floats would either be too quiet for most guests to hear, or so loud that the devoted fans waiting in that premium spot would rupture their eardrums! In order that everyone have an enjoyable experience, the floats need the help of the parkwide audio system.

The parkwide audio system is the network of cleverly hidden speakers you hear throughout the park. During normal daily operations, this system provides background music and sound effects to enhance the themed experience. It also gives the staff the ability to page and make announcements. Since the job of the parkwide audio system is to distribute audio to everyone in the park, it’s the perfect vehicle to distribute the parade audio as well. Sounds easy, but there’s a catch; in order for that concept to work, the parkwide system needs to synchronize with the floats as they pass by.

Why is this so difficult, you ask? Well, to start, audio-to-audio delay is one of the most unforgiving scenarios when it comes to synchronization. The human brain is quite sensitive when it comes to perceiving sound. Minute variations in audio delay, amplitude, and frequency are carefully analyzed by our brains to perceive such things as which direction a sound is coming from, and how far away it is. If the audio playing from the parade floats is out of sync with the parkwide audio, the result can be quite unpleasant. Although the amount of delay that affects each person varies, a common goal is to try to keep these audio systems synchronized to within 10ms of one another (10ms = 10 milliseconds; a millisecond is one-thousandth of a second).

So… what we’ve got is a parkwide audio system that runs from playback equipment that’s locked away in an equipment room somewhere in the depths of the park, and a bunch of battery-powered vehicles with their own separate audio playback systems. Keep in mind that there is no wired connection between these systems and that the floats will be moving throughout the park during this experience. Under these circumstances, how in the world do we achieve synchronized playback with a precision better than 10ms? While there are many approaches to solving this problem, the more effective ones revolve around the idea of having a shared reference clock that’s distributed wirelessly. In the earlier days of parades, this clock would be broadcast using DTMF tones (dual-tone multi-frequency signaling, such as those used in touch tone phones) or SMPTE longitudinal timecode (LTC). The floats and parkwide playback systems would both receive this transmission, lock to these distributed clocks, and trigger simultaneously with a respectable level of precision.

Nowadays, the same shared clock principles still apply, but the distribution methods typically adhere to more modern industry standards. This includes methods such as GPS and network-based clock standards like NTP and PTP (network time protocol and precision time protocol). As long as the floats and parkwide systems are equipped with audio playback equipment that can precisely lock to these standards, they can all share a clock that is accurate, and perform to within microseconds of one another. The idea is that all systems can be scheduled to begin playback at a very specific time based upon this clock value. Even though it may take some time for control packets to bounce around network switches and fly through the airwaves on wireless networks, it doesn’t matter. Every system readies itself to start playback at the scheduled time and, as a result, they are able to achieve microsecond-synchronization.

Loops, floats and control

Once the parade system has this ability to synchronize audio playback between the floats and the parkwide system, it has the ability to provide the foundation of a parade show: the parade loop. To elaborate, most parades are designed around the concept of a show, typically several minutes in length, that is designed to loop seamlessly. Although the show elements would vary greatly, the duration of the show on a given float would be the same as that of the other floats. These shows would all be designed to loop synchronously along with the parkwide audio and repeat until the parade is over. Thanks to the shared clock, the parade system can retrigger the parade loop in perfect sync every time.

With synchronized parade loops, we’re ready to move on to the next major dilemma; those pesky floats that insist on moving. Most parades will have unique show elements for each float, each with corresponding, unique audio tracks that the parkwide system will need to play, and play only from speakers near the float as it moves along the parade route. This requires the parade system to track the position of every float so that it can route audio to the speakers that are nearby. To do this properly, there must be an intelligent control system onboard the float that is capable of interfacing with technologies like wheel encoders, GPS, and/or RFID scanners to determine position. This control system must then relay that position to the control system that’s managing the parkwide audio system so that it can route to the appropriate speakers. By deploying the right show control systems in conjunction with the flexible routing and mixing capabilities of a modern DSP (digital signal processor) platform, the complexity of this task is greatly reduced.

Equipment and environment

Last, but not least, the unique environment of the float itself should be considered. As with pretty much anything else in theme parks, story and theming come first so the technology equipment for a given float will inevitably be housed and concealed in its dark, cramped, in-between spaces. Space, power consumption, and equipment weight are, therefore, significant factors of float design. Other factors to take into account include the constant vibrations and exposure to outdoor elements; factors that mainstream A/V equipment is not designed to handle. Given these considerations, when making equipment choices, ideally those choices should point to something that is compact, efficient, DC-powered, and specifically made for this type of application. These types of solutions empower operations and maintenance staff to keep the parade running at its best.

When you combine the power of distributed clocks, float tracking, flexible show control, and float-friendly hardware, you have a solid foundation for an amazing parade that not only looks great, but sounds great too. • • •

As Chief Innovation Officer at Alcorn McBride, Scott Harkless ([email protected]) works closely with clients to determine their biggest areas of need and leads a team of problem solvers to come up with creative solutions. He draws upon experience in product development, system commissioning, client training, marketing, and sales.



Alcorn McBride: Tech talk

Scott Harkless
Scott Harkless
As Chief Innovation Officer at Alcorn McBride, Scott Harkless works closely with clients to determine their biggest areas of need and leads a talented team of problem solvers to create the products used in many of the world’s most popular attractions. He draws upon his experience in product development, system commissioning, client training, marketing, and sales to ensure that the products stamped with the Alcorn McBride logo exceed client expectations and offer value to the entire industry.

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