One of the great parts about my job is that I get the chance to work on a wide range of exciting projects, each with their own unique challenges. The particulars of each project help keep me on my toes and ensure that we never apply a “one size fits all” approach. I wanted to share with you a recent high school stadium audio upgrade project that I worked on which is a great example of overcoming challenges – and bringing in external resources to help bring things home.
A customer came to us with an opportunity to upgrade a high school football stadium’s sound system, which was working but in need of a refresh. The existing sound system consisted of a series of Community outdoor loudspeakers mounted above the home side press box:
Although these speakers were functional, attendees were complaining that announcements and music could not be heard over the crowd noise, particularly at larger events with a full capacity crowd, and particularly on the visitors’ stands, which are over 400’ away on the other side of the stadium.
My first thought was to add speakers to the light poles on the visitors’ side to improve coverage and intelligibility. However, according to the customer, the school was unwilling to add trenching to the other side for this project, and there were no known pathways connecting the two sides.
With this disappointing piece of news in hand, I knew I needed a second opinion, so I decided to reach out to one of the most capable and helpful people in the industry – Harman’s Dave Tewksbury. Dave is an amazing and knowledgeable resource on all things JBL and BSS, and I knew he could help to find a creative solution.
After explaining the limitations of the project, Dave surprised me when he stated that JBL’s AW series of speakers (the AW566 in particular) have the ability to project over that distance when paired with the proper amount of amplification.
But what is the proper amount of amplification? In order to determine that, we need to have a target sound pressure level at a given distance. Although ideally we would want something above 90 dB SPL to truly overcome all crowd noise, the amount of amplification required to hit that from 430’ away would be both impractical and would overload the speaker.
Together we settled on a target of 85 dB SPL, which according to both Crown’s amplifier power calculator and JBL engineers, would require approximately 1083 watts of power for the AW566:
Finally, something we could work with! We settled on the Crown DCi 2×1250 to power (2) JBL AW566 loudspeakers mounted above the press box to provide sound to the visitors’ side. The home side situation was much easier to solve for – it simply required selecting speakers with the appropriate coverage patterns. Those turned out to be (3) JBL AWC82 speakers, powered by a Crown DCi 4×600. We also recommended relocating the home side speakers so that they would no longer be in the acoustic shadow of the press box roof, as the previous Community speakers were.
Through all of this legwork we were able to provide the customer with a reasonably-priced solution to drastically improve the acoustics and intelligibility of their sound system. We were able to navigate challenges which prevented implementing the “ideal” solution, and were able to provide them with an easy-to-implement significant upgrade to their current system.
My thanks as always to the invaluable Dave Tewksbury, as well as all of the great folks at Harman, for their continued support, knowledge, and help!
If you are interested in more information on amplifier power and speaker ratings, Crown has an excellent guide on their website, and if you need help with a complex or challenging audio project, simply send an email to [email protected] and our team of experts will be there to help!
About the Author
John Rossman | CTS
BDM II – Technical Specialist
Supported Manufacturers: Harman Professional – AKG, AMX, BSS, Crown, DBX, JBL, Lexicon, Martin, & Soundcraft
