How Theme Parks Work

Digital Audio Systems

Audio systems have advanced significantly as digital signal processing has become more prevalent. However, before studying the new, let's take a quick look at the old.

Theme park projects can be quite large in magnitude, and large projects require slightly different thinking for reasons of efficiency. Ideally, to reduce spares and to and to make it easier to maintain a highly trained maintainance staff, the same type of equipment should be used in as many places as possible. This can put a cramp in the designer's choice of devices, but this is where creative products come into the picture.

Up until the early 90's, theme park systems relied upon racks of card frames comprised of mixing modules that served as a common type of gear that satisfied all possible applications. Some parks made do with off-the-shelf products, the more adventurous ones used custom engineered products. Equipment was configured through a combination of wiring and switch settings, which made configuration work quite challenging, particlarly in large attractions where hundreds of audio channels could exist.

In large systems, equipment racks, then and today, are thought of as subsystems. As the diagram above indicates, each rack has a functional purpose. Racks are interconnected using large cables with robust multipin connectors, such as ELCOs. The interconnection scheme is chosen to efficiently divide labor. Racks of equipment are built and configured in specialized shops, and electricians interconnect the cabinets using the multipin cables. The negative of this scheme, of course, is that it is very labor intense.

While the system functions haven't changed much, today's systems are evolving into a new form. Audio in the '90's took a turn when flexible audio digital signal processing (DSP) was introduced by Peavey Electronics: the MediaMatrix™ system. This was the first of its kind, and for many years, the only of its kind. Originally designed by Peak Audio, now a division of Cirrus Logic. Today, there are several products of this class available, some with very sophisticated audio networking, which we'll explain later.

Flexible DSP signal processing allows the system designer to create the exact system required through a computer-driven graphical user interface (GUI), without special wiring. These systems automatically program their DSP-based hardware to perform all audio functions as drawn by the system designer. In addition, the designer can create sophisticated GUI's for system setup and for operator control. This class of product eliminates lots of rack wiring and configuration. It also makes the inevitable "field change" quite a bit easier. Below is an example of one such GUI created on a MediaMatrix system in the 90's. (click to enlarge)

In the upper left corner, you'll see a set of purple buttons that are used to select an input, an output, or a combination of channels, for local monitoring. On the right, you'll see bar meters used for visual indication of audio levels. The series of little lights below, some of which are lit bright green, are indicator lights for system functions. Rather than create a physical panel with a as many lights, this soft panel was cheaper and easier to implement. We talk more about how this panel interfaces to Show Control on our Controls page.