The Davies Symphony Acoustical Canopy Control System
This page is dedicated to the hard working people who designed and built the Davies Symphony Acoustical Canopy Control System.

Acoustical Design: R. Lawrence Kirkegarrd

Concept Design, Mechanical Winch Design: George Van Burren

Winch Assembly Contractor: Holzmueller Inc. + Radiant Enterprises.

Canopy Control System Design: Radiant Enterprises.

Executive Management and Overall Electronic Design: Gerth Hansson

Project Management, PCB Layout, Electronic Testing, Safety Engineering: Ted Chavalas

Electronic Design, Chief Programming Engineer: Gregory Pulier.

Control Software Engineer: Nat Fast

Installation Supervisor and Current Operator: Jim Jacobs


Brief Specifications:

Control Computer: Macintosh G4 400 controls 59 independent winches with height, roll and tilt via AppleTalk network with PhoneNet Topology.

Each winch each has 3 Microchip PIC 16C57 processors with triple redundant error checking and watchdog timers. Winches also can be controlled via programmable handheld controller or manual switches located on the winch. In the event of a power failure during a move, each winch can safely shutdown and store it's current position in non volatile memory running on power stored in reserve capacitors.

Vertical Travel 70 feet Max. 0.1 inch accuracy.

Roll and Tilt up to 40 degrees with 0.01 degree accuracy.

There are 177 motors controlled by the system.

System computer can store unlimited number of preset configurations called "Concert Positions". Each winch can also store 10 emergency preset positions that can be called from the main controller or the handheld controller.

System has been in continuous daily use for 8 years. Although there have been some accidents the system has been remarkably reliable and safe.


Winch Design and Programming starts in 1990. Chief Electronics designer Gregory Pulier sits at his Macintosh + Programmers Workstation.
Project Manager Ted Chavalas seen here near area 51 holding a Radiant Common Sense AppleTalk device.

This front page article from 1990, briefly talks about the project and shows a picture of the Canopy model.
Handheld "Smart" Remote

Click below to read the Opening Night Review from 1992!

The Update 06/20/2001
A shot of the New Control Stack.
Nat Fast works on updating the Canopy Control stack while Jim Jacobs observes.
The Control Room.
See the Canopy in Action!

NEW MOVIE !!! Streaming Download

57 meg. QuickTime.

See The canopy in this high resolution VR movie shot with Panoscan. This movie Requires FLASH.