Sioux City, IA (May 25, 2005)–R&D Industries recently installed a Nexo Geo S tangent array sound reinforcement system at the historic First Presbyterian Church of Sioux City, Iowa. A simple single array of white Geo cabinets has brought intelligibility to this highly reverberant space.
First Presbyterian was built in the early 1900s. The main sanctuary has a classic and timelessly simple design, with the pipe organ featuring on the front wall facing a large balcony. This balcony overhang presented some unique challenges since it was basically removed from the main acoustical space, which made it very difficult to hear material from the original speaker system.
RDI solved this problem with under-balcony speakers. A trio of Nexo PS8s were employed to provide sound coverage in areas under the balcony. The main array’s design, however, did alleviate the need for upper-balcony delayed coverage, which would have been necessary with a conventional speaker system approach.
Using acoustical modeling, the design concept featuring a single array of Nexo Geo S showed sound pressure level deviations in the seating area were minimized in comparison to other designs considered. Said RDI project director Todd Berger, “this is a pretty reverberant space, so, by utilizing a line array approach, we were able to alleviate a majority of the reflections from the hard-surfaced ceiling, keeping intelligibility relativley high.”
The array consists of seven S805s and a pair of S830s hung at a height bumper bar of 33 feet. The bumper bar down angle is -8.5 degrees and cabinets are splayed -2, -3.15, -5, -5, -5 ,-5, -5, -17.5, -17.5. The bottom S830 is the only box to use the CDD horn plate for 120 degree horizontal coverage. This provides coverage in the balcony which is 74 feet back from the front of the cluster.
Functionality of the system operation includes monitors for performers at the stage level, recording capabilities, and six channels of Shure UHF wireless microphones. Large diaphragm AKG stand mounted microphones are used for large-group recording as well as reinforcement, and Sennheiser handhelds were chosen for close vocal applications.
Marantz recording and playback electronics were installed and the system uses CX-series amplification from QSC throughout. Mixing is done by a Biamp Audia processor for the automatic mixing of speech applications as well as an Allen & Heath 32-channel mixing console for more complex tasks in manual mode. The loudspeaker processing was done using both an NX242 for the Geo S array and the PS8 TDcontroller for the underbalcony delays.
R&D Industries, Inc.