“It was clear from our initial discussions with Mr. Fontana that he would not compromise on the audio equipment’s quality and performance,” the installer continued. “After that phone call we knew we would be using Lab.gruppen power to drive the MM-4s. We have also started using Lab.gruppen amplifiers for our concert systems, because they sound great and are reliable; it was this kind of performance that we needed for the River Walk project, so the CX20:8X made perfect sense.”
Cables to the 16 Meyer MM-4 loudspeakers – four mounted along the canal, eight beneath the bridge and four along an additional walkway – are carried via steel conduit. In contrast to conventional low-power 70 V, transformer based systems, the MM-4 connects directly to an amplifier and is capable of producing high SPL with reduced distortion.
The loudspeaker houses a single four-inch cone driver with a 16-ohm voicecoil mounted in a sealed enclosure; it draws 150 W peak, and produces a reported 112.5 dB peak SPL. The enclosure’s black anodized, extruded aluminum serves as a heat sink to cool the driver’s voicecoil. “We specified Belden all-weather outdoor-rated cabling,” Edwards said.
The outdoor installation posed its own unique design challenges. “A major consideration was to protect the systems from weather, theft and vandalism. We decided to house all of the playback equipment and amplifier racks in a central, custom-deigned enclosure and run individual signals to each of the suspended loudspeakers,” the installer explained.
“The overall design had to cover three primary aspects: One, the enclosure needed to provide a safe haven for the equipment, safe from public access; two, it needed to be protected from the elements; and three, it needed to be temperature controlled.” Fabricated by DDB Unlimited, the rain-proofed enclosure features 19-inch rails for the rack-mounted equipment, plus a venting system that forces air through the hood.
“We suspended the enclosure some 12 feet in the air,” Edwards recalled, “using custom strapping and brackets.”
The equipment enclosure is mounted beneath the bridge out of the worst of the weather, with conduit routed away from reach of the public. “We used thick-gauge steel for the enclosure, with perforated covers that were custom designed in Austin,” the installer continued. “The Meyer MM-4 loudspeakers are a weatherized version with a water-seal kit and sealed EN3 connector for cable termination.
“Each loudspeaker is mounted within a 10- x 10- x 8-inch steel enclosure with a moveable U-bracket yoke and swivel bracket to allow them to be aimed as necessary. Within the river zone the loudspeakers are mounted between 12 and 16 feet above water level, while in the sidewalk areas they are between 8 and 10 feet in the air. It is a very robust and well-engineered system.”