When management at the Edward Jones Dome in St. Louis, home of the St. Louis Rams NFL team, determined they needed to improve their music playback capabilities they decided that adding speakers, subwoofers and amplifiers to the main system was not the best solution.
Instead they wanted a sound system that would be flexible enough to work for the home football games as well as for a number of applications and in different locations year-round.
For their solution they turned to Tony Badamo, pro sound and AV specialist at Tech Electronics in St. Louis, to configure and package new, portable on-field systems that would provide the audio quality and flexibility they required.
Tech Electronics immediately turned to One Systems Inc.‘s loudspeaker brands. Having successfully installed them in a number of outdoor and indoor sports facilities, they were confident they could create a system that would meet managements exacting specifications.
“We’ve used One Systems products for a number of applications and they always deliver the kind of sound our clients demand along with tremendous reliability,” Badamo explains.
Each system was required to deliver 128 dB SPL with a frequency range of 33 Hz to 20,000 Hz + 3 dB. In addition each speaker stack had to be easily movable by one person, fast to set up, yet deliver high output and be capable of projecting its sound long distances. The stacks had to be self-contained including its own mobile cart, power amplifiers, processing, and all AC and signal cabling and the full-range system and subwoofer had to be permanently attached to each other.
But that wasn’t all. The amplifiers had to deliver sufficient power to ensure 3 dB of headroom and each stack had to operate from a standard 20 A 120 V ac circuit and had to include a 15.15 m / 50 ft ac mains cable. To add to the complexity, the rig could be no more than 1.8 m / 6 feet tall, so that it could easily be moved through the stadium’s tunnels onto the field, or into storage to ensure that sightlines weren’t interrupted.
Last but not least, the speakers had to be “industrial grade” with durable enclosures and metal grilles that could withstand impact without damage and they needed to be black and have no manufacturer’s logo visible.
With all of that in mind, Badamo determined that four full-range vertical array/subwoofer stacks placed at each corner of the field would cover the stadium’s large floor area plus be heard above the crowd. This concept would offer the coverage and portable flexibility the stadium was looking for.
Ultimately each of the four stacks consists of one One Systems 312CIMs, one On Point Audio OPA-218-Sub and one Powersoft K3 DSP amplifiers. One channel of the Powersoft K3 DSP amplifier drives each loudspeaker and subwoofer.
The 312CIM is a vertical array loudspeaker featuring three 12-inch woofers with large-format voice coils and a coaxially mounted large-format compression driver. The loudspeaker features 1,200 watts continuous power handling and delivers a 60-degree conical coverage.
The OPA-218-Sub utilizes two powerful 18-inch woofers with 4-inch voice coils housed in a Vented Slot enclosure with 1,600 watts continuous, 6.400 watts peak power handling.
Because the subwoofer enclosures are short and slim but very deep, they were the perfect base for permanently attaching a 312CIM to the top. In order to make the system easy to move and connect, Tech Electronics turned the OPA-218-Subs upside down and screwed large-diameter locking casters on the bottom of the cabinets. Turning the subwoofers upside down also exposed two front-mounted CNC cut handles making it more comfortable for one person to easily move the rig.
In addition to the 312CIM, a 5-RU metal rack was also attached on top of the subwoofer to house the Powersoft K3 DSP, along with two drawers for long AC cables and SLR-type signal cables and accessories.
“The system delivers everything that the Edward Jones Dome asked for,” concludes Badamo. “It has tremendous bandwidth, high output and shakes the building when it’s played while still delivering the sonic nuances of the music perfectly.”