Located an hour south of Chicago in Bourbonnais, Illinois, Olivet Nazarene University serves over 4,500 undergraduate and postgraduate students. In order to support the campus community and to promote student health and wellness, the university recently completed construction on the new Student Life and Recreation Center. Among many other amenities (including a four-story climbing wall!) the new facility features a 72,000 square-foot field house with four full basketball courts ringed by a running track. Olivet Nazarene University plans to eventually use the space for concerts, ceremonies, and other large events in addition to its day-to-day activities. With that goal in mind, the field house sound reinforcement system is a high-powered combination of Danley Sound Labs GH-60 Genesis Horns (with SH-100 loudspeakers for fill) paired with Danley TH-118 subwoofers which are configured in a steered cardioid array.
AVI Systems, of Bensenville, Illinois, designed and installed the system with significant design and commissioning assistance from Johnson AV Engineering of Chicago. “The school officials already had their heart set on the sound of the Danley GH-60 Genesis Horn,” explained Aaron Johnson, president and principal engineer at Johnson AV Engineering. “AVI brought us on board based on our prior experience with Danley systems. I agreed with their choice. The GH-60 sounds great and, like all Danley boxes, exhibits excellent pattern control. Good pattern control was essential to keep direct energy off of the walls as much as possible.”
The system they arrived at uses six Danley GH-60 Genesis Horns in two groups of three arrayed in a ring at the center of the field house. A Danley SH-100 provides down-fill below each cluster of GH-60s. Depending on the configuration of the room, the university’s A/V staff can use the entire ring of loudspeakers for full 360-degree coverage or they can split the ring in half and use only one side or the other. A line of ten additional Danley SH-100s cover the bleachers along one side of the room.
Initial acoustic models of the space suggested the room would have a very long reverb time. Johnson knew that it would be essential to control the low-frequency energy. To that end, he worked with Danley Sound Labs’ DDT 2D modeling software to design a steered cardioid subwoofer array whose pattern would approximately match the coverage pattern of the GH-60 Genesis Horns. He used two hangs of two Danley TH-118 subwoofers each. Each TH-118 is separately processed and powered, and the net effect delivers low-frequency energy centered at 60Hz in a ring which is steered down towards the floor with very little LF energy radiating up towards the ceiling. When only half the space is used and the GH-60 Genesis Horn ring is cut in half, the subwoofer array can also be cut in half to focus low-frequency energy in the appropriate direction.
Biamp Audio DSP provides all of the system processing, with Lab.gruppen C-series amplifiers providing the power to the Danley loudspeakers and subwoofers. AVI designed the system so that the main GH-60s, the downfill SH-100s, the bleacher SH-100s, and the subwoofers are all capable of independent control. For daily use, a Crestron control system provides intuitive input selection and volume control.
“The reverb time turned out to be close to 5.5 seconds,” said Johnson. “That’s very long, but with the high directivity of the Danley loudspeakers and the subwoofer array, the direct-to-reflected ratio is really good. The original plan called for acoustic treatment, but when the school officials heard the installed system and considered their budgetary priorities, they opted to forestall the acoustic treatment. It’s really to Danley’s credit – a less controlled system would have required significant acoustic treatment just to sound passable.”