Cambridge, MA (May 30, 2006)–In one of the primary lecture halls at the JFK School of Government at Harvard University, a recent audio system upgrade is making it easier for everyone to participate. Adtech Systems, a Wayland, Massachusetts, AV systems integrator, installed a new zoned, mix-minus microphone/loudspeaker system that improves the ability of everyone in the classroom to both speak and be clearly heard. The project was headed by Adtech’s design engineer, Michael Merrill.
While a similar system had been in use since the hall was last upgraded in 1990, it was not sophisticated and often malfunctioned. The existing loudspeakers and microphones were no longer performing well, and the school’s directors decided a new sound system was a high priority. Their goal was to ensure that students would be able to focus their full attention on the dialogue and discussion processes, rather than constantly dealing with the mechanics of audio technology.
The focal point of the hall’s new audio system architecture is a SymNet DSP Audio Matrix from Symetrix. The digital signal processing, mixing and routing system manages the complex task of distributing audio from 52 microphones to some 120 loudspeakers. The mix-minus configuration allows a speaker’s voice to be routed from the microphone to all speakers in the hall, with the exception of those in the speaker’s immediate vicinity.
Employing two SymNet 8×8 units, four Break-in 12 devices and two Break-out 12s, Merrill was able to configure a solution that established 27 loudspeaker zones, and the ability to route microphone audio to the appropriate zones.
“SymNet was the only cost-effective way to juggle that many inputs and outputs. It was the best choice to create a large matrix, mix-minus system that eliminated the possibility of feedback to the speaker’s vicinity, but allowed voice to be sent to the other 26 of the 27 zones in the hall,” said Michael Merrill, the Adtech engineer who designed the solution. Using SymNet, Adtech was able to replace a mechanical, analog system in the hall that employed no zoning, but rather doorbell-style relay buttons that could be pushed by the speaker to activate the microphone and mute the loudspeakers in his or her vicinity.
SymNet’s internal architecture was essential to deploying a system that could handle such a large number of inputs and outputs, Merrill said. “One of SymNet’s most helpful features in this application was having the proprietary SymNet buses that could be assigned to either send or receive,” he says. “We needed a lot more than the 32 inputs that a CobraNet configuration would allow. Using SymNet’s SymLink communications feature we can have up to 64 buses of any combination.”
In addition to routing audio from microphones to the loudspeaker zones in the tiered, theatre-style seating lecture hall, SymNet also is configured to send audio to recording devices. With the new SymNet-based system, up to one-hundred students can now have much quicker and easier exchanges, without having to worry about the possibility of feedback or managing a clunky microphone-muting system.
Other equipment used in the renovation were Tang W3-594S three-inch shielded loudspeakers, Audio Technica U891R boundary microphones with a push to talk switches, and Shure MX418C gooseneck mics. And while all of this gear was an essential part of the audio system upgrade, SymNet was the link in configuring the system to meet the lecture hall’s unique demands.
Noted Merrill, “From a programming standpoint, SymNet was easy to work with. It’s drag and drop GUI is very easy to program. We were pleasantly surprised. But the real advantage was that SymNet helped produce great sound quality in the hall.”