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Valley Baptist Church’s Journey to Turn AC Noise Into a Clear Message
By Tom Holmes - Live sound/studio engineer, consultant, and educator in the San Francisco Bay Area
In 1982, Valley Baptist Church in San Rafael, CA, endeavored to build a new, 350-person-capacity sanctuary on the property adjacent to their existing building. The project was to be completed on a shoestring budget. So while contractors did the foundation and framework, parishioners did the rest. From sheetrock to flooring, electrical to sound, the church members donated sweat, equipment, and anything else needed to complete the job. The dedicated parishioners actually worked around the clock in shifts until the new and modern sanctuary was finished. This was no small feat to be sure, and the new church building stands as a shining example of what can be done with teamwork.
When senior pastor Christopher Losey arrived in the mid 1990s, he was amazed by what had been accomplished, but also realized there was quite a bit of room for improvement, especially when it came to the sound system. Since most of the equipment had been donated — the majority being well used even in 1982 — the only real design work had been to incorporate everything to work together as best as possible. “We lived with the constant buzzes and hums for years,” says Losey. “The worst part was the occasional radio station that would come in clearly through the speakers in the middle of the message.” When one of the original center-cluster horn drivers failed, and the budget finally permitted, expert advice was sought to help solve the inherent sound problems. That is when I was called into the project as a consultant.
Upon first survey of the system, it was obvious that some basics needed to be addressed. Since the electrical had been done on the cheap, that seemed like the place to start. Upon entering the basement utility room, I noticed two huge black boxes stacked one on top of the other, with 8-gauge, cloth-covered wires hanging out. There were also a number of stage-pin connectors with old 12-gauge wire attached and freely creeping up the walls like ivy.
It looked like something right out a mad scientist’s lab in an old horror film. As it turned out, this was the three-phase power module for the church’s stage lighting set up! Evidently, it was an old retired road rig that had been purchased from a large tour company at the time of the new construction and made to fit the church’s needs. Losey fondly remembers powering up the lighting monstrosity: “We would flip the lever and it sounded like a 747 taking off.”
While this seemingly homemade unit had served them well over the years, safety concerns alone required its replacement. The power for the sound system came from a split-off of one phase before the 400-plus-pound lighting beast’s terminal. No power conditioning was in use in either the stage rack or front of house positions. Obviously, these were the first issues that needed to be addressed.
The old lighting unit was broken down with a sledge hammer, removed piece by piece, and replaced with a modern 2-rack-space, three-phase, DMX-controlled unit. An electrical contractor was called in to install dedicated circuits for the sound system with home runs from the stage rack and front of house positions.
A Furman PS-Pro Series II 20-A power sequencer/conditioner was installed in the amp rack and a PS-8R Series II 15-A sequencer/conditioner at the front of house.
Powering up the system is a one-switch operation from the front of house, ensuring proper start-up and shut-down order to avoid potentially damaging speaker pops. Furman’s linear filtering is unparalleled in reducing asymmetrical AC noise and the non-sacrificial surge protection lends peace of mind. Losey considers this protection aspect “good stewardship of your equipment.”
A new mixing console was installed and finally a new speaker system replaced the old horn cluster. “The system is clean and sounds great now,” says a happy Losey. “It is what you don’t hear that counts, no humming or popping or buzzes and no radio stations!” The system is exceptionally quiet, even on start up and shut down. “The power sequencing makes life easier and leaves one less thing to worry about,” says Losey. “It’s a fail-safe for whoever is operating the system.”
While several changes were made to improve the sound at Valley Baptist, the majority of the problems had come as a result of unclean power. Of the many solutions to remedying noisy AC, power conditioning is one of the most effective and important. With our aging power grid providing dirtier and dirtier power with each passing year, and the ever-growing use of electronic devices with noise-generating power supplies, AC noise can couple into audio circuits and become audible or at least decrease efficiency and performance of the equipment by raising the noise floor.
A power conditioner with a well-tuned linear filtering circuit is one of the best investments a house of worship can make. Linear noise filtration works with asymmetrical AC noise and reduces it as much as 40 dB at 20 k. This is a key aspect in the new clarity of the sound system at Valley Baptist. The linear filtering circuit is not only attenuating pre-existing noise, but will continue to be effective into the future as AC noise changes and increases.
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