Calgary Stampede Grandstand

We have provided sound system design services to the Calgary Stampede's ETS department for the multi-year, multi-phase upgrade of the sound system in the Stampede Grandstand. 2009 marked the completion of the main exterior loudspeaker systems, which finally revealed the greatly improved audio quality of the electronics upgrades of the audio systems implemented since the project began.

When we were engaged in 2004, the majority of the sound system in the grandstand dated back to 1989. The system components had passed their reliable service date, and the loudspeakers were no longer up to the growing demands of the Rodeo and Grandstand show. It was not unusual to need to do major speaker repairs every spring before the annual Stampede event.

The goals of the system replacement and upgrade were to provide better sound quality throughout the main grandstand and infield, better sound coverage of the expanded seating areas, and above all, much better reliability so that none of the Stampede guests would have to complain about not being able to hear.

The initial phases of the upgrade began with the replacement of several equipment racks worth of analog signal processing with a Biamp Audia Flex Cobranet equipped DSP, and the simultaneous expansion of the audio trunks between the stage and sound booth with a Whirlwind Cobranet based audio snake. Since the conduit infrastructure was already near capacity, the ability to get 64 audio lines over a single CAT6 cable was a tremendous benefit. The Cobranet based audio transport also enabled easy integration with the new audio processors. A dedicated fiber optic based Gigabit network was installed for the grandstand audio system between all the audio equipment rooms.

The audio amplifiers were all replaced with Crown CTs network controllable and monitored units, with the zoning and output power configured for the final system configuration. The amplifier room was also split into two to reduce the speaker cable runs for the roof deck mounted loudspeakers in the 700' long x 100' high building. The upper rack room contains the amplifiers for the roof deck and press box speakers. The original rack room just contains the amplifiers for the lower levels of the building.

Various interior and smaller scale exterior speaker zones were replaced and upgraded between 2004 and 2008. 2009 saw the replacement of the roof deck speaker system. The original system had 16x Altec MR64 Mantaray/299-16A horns/drivers, 16x Altec 816A bass cabinets and 6x Servodrive SDL-4 bass horns, plus 16x Electro-Voice S-200 upper deck speakers. The new system makes use of 40x Comunity M4 coax systems for the upper seat deck, main seat deck/tarmac and infield coverage, plus 8x dual 18" Sonus subwoofers in the roof, and one R6 bass horn on top of the roof for the infield.

The new system has 20dB of head room at nominal operating levels, helping ensure a long lifetime for the speaker system components. More importantly, the distortion at nominal operating levels is down by >10dB, resulting in a truly impressive high fidelity sound quality. The low compression ratio of the mid and high frequency compression drivers, along with the Comunity horn design, provide and incredibly open and crisp sound quality, even at 90dBA in the seats or infield. The coverage of the system was exactly as predicted in the EASE model, with the levels and overlap areas as predicted by the model. The sound system can produce a uniform coverage of 90dBA over the seating and infield competition area. Even the sound levels between 40-100Hz are uniform over that entire area.

EASE model plot - direct sound

There are still some interior areas of the building scheduled for upgrade, but the new main sound system should exceed the 19 year service lifetime that the 1989 upgrade provided, without the need for so much regular repair and replacement of speaker components that has been required.

Test fit of new speaker clusters

The sound system installation work was all done by the Stampede's own ETS Department. The fabrication of the speaker cluster frames was done by Trailmaster Off Road Industries Ltd. in Calgary. The fabrication of the north and south end clusters was a story all on its own.