Oxford University gave this brief because a Grade I listed building needed refurbishing with a sound system.
The Sheldonian Theatre is the second work of Sir Christopher Wren. Because its design resembles that of a Roman theatre, it is called a theatre even though plays are not performed in it. During the last two years re-ordering included cleaning, repairing and painting the ceiling. All the internal decor has been impressively restored to exactly as it was in 1649 when it was opened.
The project was managed on behalf of the University by David Holt who rightfully insisted that the building needed a high quality sound system which could not be fixed to any of the original finishes. It should be invisible, and needed to serve ceremonies and lectures in the two different orientations.
Meeting the brief
Brian Hillson of B&H Sound was given the task of designing a system to meet his specification and chose speakers imported by Sennheiser UK from Italian manufacturer K-Array. The main units were just 35mm wide by 17mm deep and arranged in a one meter column.
Twelve speakers from the Vyper range were chosen and fixed to the rails of portable steps up the organ chamber, as well as door frames and the sides of the buttress on the ground & third floors. Because of the slim dimensions, they were able to be fixed discretely. So much so, that the B&H team had to photograph them before they were spray painted to match the special colours used in the refurbishment.
The challenge of the surrounding galleries were overcome by equally discrete miniature speakers from the Bose Freespace range where the the team used 13 Freespace 3 cube speakers & 6 Freespace DS16 Speakers, all in a white finish & arranged in a distributed infill design.
The K-Array Sub bass speakers were concealed within the same portable staircase, through ported enclosures in the steps, and powered by 2 KA7 & 1 KA10 amplifiers.
The custodian was provided with an Allen & Heath PL6 fader plate to call up the pre-sets to change the orienation of the system from north facing to south facing, programmed on an Allen & Heath iDR8 Digital System Controller.
It was also extremely important that all cabling be low smoke to meet stringent site conditions.
Oxford Universite staff were present when the speakers were demonstrated. They were impressed by their directionality and controlled dispersion in the verical field. When one professor heard the completed system, he asked, “by the way, where are the speakers?” – Probably the best testimonial to the success of the installation!