JANDS NEWS
James Hay Theatre, Christchurch
29 October 2009
The James Hay Theatre was built in 1972 as a raked inner circle and upstairs gallery performance theatre with minimal sightline obstructions to the stage. It can entertain a capacity of approximately 1000 guests.
The sound system was last upgraded in the early 1980’s with left and right, dual 15 inch and horn Renkus Heinz Smart bins, controlled by the smart proprietary two way electronic crossover. These enclosures were integrally mounted in the left stage and right stage, wooden tormenter panels. This permanent position didn’t allow for adequate sound coverage to the outer stall seating and created a hot spot right through the middle of the inner circle. The position also had limited throw to the rear outer stall seats under the overhanging gallery structure and created a decibel drop of 6 to 10db at the front of house mixing position.
John Spensley, John Parkinson and Dave Stone of Vbase, along with David Fuller of Jands, main target was to upgrade the sound coverage to all seats in the theatre including the outer stalls and front of house mix position. Doing so required moving the amplifier racks out of the old operations room situated in the roof of the theatre above the gallery, some 70 metres from the stage. The amp racks were housed in a small ex-broadcasting room, prom-side of the stage, to minimize all system noise from long cable run lengths. All speaker way lines and cross stage patch plates needed to be replaced, and new technical earthed power to the front of house mix position installed. Left and right speaker clusters for the downstairs general circle and the upstairs gallery seating had to be flown independently of the proscenium arch and stage wall structures and a delay speaker system covering the seat in the outer stalls underneath the overhanging gallery needed to be installed.
These requirements were achieved by creating identical hanging points attaching to the high steel in the theatre roof cavity above the stage left and right positions in order to suspend the top and bottom speaker enclosures from a single fly point. Through a 50ml gap between the wooden tormenter acoustic sail structure, a pre made 8ml steel wire 12 metres long, was dropped. Utilizing the top M10 threaded suspension fly points on the upper speaker enclosure they bolted a designed box tube cross bar with a central eye bolt and attached the steel wire and swaged O ring pickup to the speaker enclosure, with a bow shackle. The bottom speaker enclosure was under flown utilizing the M10 threaded suspension side points, creating steel flat plates to lock the boxes together using a preset angle of approx 15 degrees. To stabilize the speaker cluster side to side movement, the speaker array angle was positioned with a permanently fixed bent steel side bar, attached to the wooden acoustic sail as a brail. The top enclosure was flown horn up and the bottom enclosure horn down. This gave excellent upstairs and downstairs high frequency coverage and also coupled the 12 inch mid drivers together for extra power.
For the delay, six passive two way speaker enclosures were mounted in the under gallery cavity structure. To replicate the seating zones created by the curved gallery structure these were wired in pairs and broken down into three time delayed zones left centre and right. These zones were measured and delayed in accordance with their relative distance to the main left and right clusters and driven by a summed left and right output from the front of house system processor.
Once time aligned with the front of house Left and Right clusters, instantly there was even and transparent sound coverage from the stage to the back row of seats under the gallery.
The final audio requirement was to add a set of small low profile stage infill enclosures for near field, low level audio coverage to the first few inner stall centre rows. This zone was missing the direct sound coverage from our main left and right clusters, as when the theatre is sold in a standard stage configuration with maximum seats in.
Equipment Supplied by Sound System Services as follows: Speaker Enclosures - House Left and Right - JBL AM6212/95 Enclosures. Under balcony delay - JBL AC2212/95 Enclosures. Front-fill - JBL AC18/26 Enclosures. Power Amplifiers Front of house - QSC PLX2 1802. Under balcony delay - QSC CS 404. System Processor - JBL DSC 280. Delay Processor - Ashly. Protea 4.24c. Third octave Equalisers - BSS FCS-960. Compression - Drawmer DL 441 Quad.
About Vbase: Vbase is 100% owned by the Christchurch City Council and is responsible for the ownership and management of four major venues - Christchurch Convention Centre, Christchurch Town Hall for Performing Arts, Westpac Arena and AMI Stadium. http://www.convention.co.nz/vbase.
About Jands: Established in 1989, Jands is a specialist distributer of world leading audio brands in New Zealand and is a privately held company. Jands Ltd., proudly represents the Harman Pro Brands, JBL, Crown, BSS, HiQnet, dbx, Lexicon pro, DOD and Soundcraft. www.jands.co.nz.
