October 2024
Contributions by Revelation’s Lead Audio Engineer, Josh Hamilton, EAW, and Mechanics Hall
— The Venue —
Mechanics Hall, located in the heart of New England – Worcester, Massachusetts – is a renowned concert hall built in 1857 and listed in the National Register of Historic Places. It is celebrated for its stunning architecture and impeccable acoustics. It’s also regarded as one of the finest performance venues in the world!
Presidents William Clinton, Gerald Ford, Woodrow Wilson, William Howard Taft, Theodore Roosevelt, and William McKinley have all graced the Hall with their presence, as well as a lengthy list of other political figures, authors, performers, and musicians. Today, in addition to being a concert venue, Mechanics Hall serves as a multi-functional event space, to include such programs as graduations, galas, weddings, award ceremonies, movie showings, and more, blending its rich heritage with modern-day utility.
One of the most prominent features of Mechanics Hall is the ‘Hook’ Organ. In October of 1864, the custom-built instrument was installed in the Hall by renowned Boston organ builders and brothers: Elias and George Hook. Made up of 3,504 pipes and 52-stops, it was the biggest instrument the Hook Brothers — considered to be among the finest organ builders in the country — had constructed to date. Now, it is the oldest unaltered four-keyboard pipe organ in the Western Hemisphere located at its installation site!
— Scenario —
The previous PA system, installed in 1991, was outdated, lacking power, coverage flexibility, and clear mid-range output. It didn’t have enough output power for anything more than speech. The coverage was not adjustable, and it had a lot of mid-range sound issues. Mechanics Hall required an updated solution to enhance its versatile performance and event needs.
Previous PA System
EAW PA System
— Challenges —
Mechanics Hall has a few unique features that make designing a sound system challenging. Balconies are the first issue. The Hall’s extended balconies required targeted coverage to avoid sound spilling onto the stage. The side balcony seats run the entire length of the hall, all the way to the front wall, far behind the down stage edge. Keeping sound in the seats and off of the stage is critical to prevent feedback.
The second issue is the stage adaptability. The main stage at Mechanics Hall is relatively shallow on its own, but can be expanded with additional decks when needed, for larger performances. The first stage extension adds six feet of depth to the stage, and the second adds an additional six feet (12 feet total). While it’s great that the stage can adapt to specific needs, the challenge comes when the audio system is also required to adapt to the various stage depths to prevent feedback issues.
— Solution —
EAW’s ADAPTive speakers, Anna and Otto, were the perfect choice for this application. Mechanics Hall was digitally modeled using EAW’s ‘Resolution’ software and a laser distance meter. Working with the folks at EAW, various system layouts were considered, but a center mono cluster was the best fit solution. By keeping the system together as a cluster in the center, the sound would be coherent throughout the Hall, the installation process would be simpler, and it would be less distracting from the historic architecture. The final design was a 270° EAW Anna array with nine modules: five modules in the middle and two on each side. The cluster would also include two EAW Otto subwoofers.
— Technical —
EAW’s Resolution software allowed for precise modeling of the Hall’s acoustics, ensuring seamless coverage across the floor and balconies. The vertical coverage adaptability of the Anna speakers addressed the stage extension issue, while horizontal coverage adjustments ensured optimal sound for every seat, including the balconies. First, the various stage size issues were accounted for because the system’s coverage area is adjustable through the ‘Resolution’ software. Second, a seamless coverage area was achieved because of Anna’s spread capabilities. Because Anna covers 100° of horizontal sound individually, three Annas flown together horizontally expands their coverage to 270° with an overlap. The Ottos were set to 100% cardioid to avoid any unwanted reflections off of the walls or organ, providing balanced audio performance and low-end extension, down to 30Hz. Four MKD526 speakers powered by EAW’s UXA4403 amplifier were used as front fills. Stealth kits were applied to all cabinets, eliminating EAW branding and creating a more inconspicuous profile.
A fully redundant Dante network was installed throughout the building from the front-of-house audio booth to the attic. Three-phase, 208v power was also added via Socapex for the Anna/Otto array. Socapex is a preferred brand of electrical connectors used in film, television, and stage lighting, to terminate the ends of a multi-cable. To accomplish this, the team had to drill from the attic through layers of concrete and plaster in the Great Hall ceiling.
Next, two large 1-ton hoist motors were installed in the attic space to support the load of the system and to make it accessible from below. These motors were mounted to a custom-built steel structure. The process was carefully planned out, using architectural drawings, and included the assistance of both an Architect and a certified Rigger, making certain that the building’s structure could support the weight of the system. Chain hooks were then lowered through two holes in the ceiling to reach the speaker support bracket. The ‘t-shaped’ support bracket was custom designed and built specifically for this project. It was floated onto the chain hooks, the speakers were mounted to the bracket, and the system was raised into place!
Drilling Holes From Attic
Building the Array
— Tuning —
Tuning the new system employed the use of EAW’s ‘Resolution’ software again for DSP control of the array, as well as Rational Acoustic’s ‘Smaart Suite’ software. A Yamaha DM7C was the interface for the laptop via a Dante Virtual Soundcard. Ten measurement microphones were strategically located throughout the Hall’s floor level and balconies for an average transfer function trace. The PA was tuned to have a linear response with a gentle 6dB tilt and a small 4dB boost in the subs for some low end weight.
Since this system is designed to program the direction of the sound, a number of presets were created for optimal sound positioning on specific floor layouts. In order to produce these settings for the various stage extensions, ‘Resolution’ was once again used. These presets store information such as adaptive parameters, EQ, and gain, and are stored in the speaker modules themselves. ‘Resolution’ triggers them from the preset manager. This feature was invaluable for this venue, and was one of the key reasons for going with the ADAPTive line.
— Specs —
(9) EAW ADAPTive Anna — 3-way, full-range array module – Anna provides all the benefits of ADAPTive performance in a high-output, mid-sized enclosure. Weighing just 135 lbs. the extraordinary output-to-weight ratio makes Anna exceptionally versatile. Anna’s 100° horizontal dispersion further extends the capabilities of ADAPTive systems; columns of Anna can be flown as mains or mixed with columns of Anya within the same array for even greater coverage possibilities. Like all ADAPTive systems, Anna is controlled via Resolution 2 software over the Dante network and utilizes the same standardized power and data infrastructure.
(2) EAW ADAPTive Otto Subwoofers — Otto is the world’s first ADAPTive subwoofer. Utilizing two Offset Aperture-loaded woofers paired with independent on-board amplification, processing and networking, Otto extends ADAPTive Performance to the lowest octaves of the audible spectrum. Otto will perfectly balance low-frequency coverage with cancellation to suit the user’s requirements; omni, cardioid, hyper-cardioid or anywhere in between from just a single module. Combined in arrays, Otto provides users with nearly endless possibilities in low-frequency pattern control.
(4) EAW MKD526 Speakers — 2-way, full-range dual-woofer loudspeaker – MKD526 is a compact dual 5″ full range loudspeaker designed for a variety of fill applications.
(1) EAW UXA4403 Amplifier —
4 inputs & 4 outputs.
Pairs seamlessly with EAW installation loudspeakers.
Optional Sync Functionality by S/PDIF linking to multiple amps.
Connect wirelessly or direct to the amplifier via a web page interface.
Configurable GPIO for additional control.
Safety and EMC Certified. Compliant to ErP & EnergySTAR.
