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Accidental Electrician: Eliminating Dreaded Sound System Hum & Buzz
An epic tale of finding and eliminating a system's long-time and ongoing hum and buzz issues. Just who was the culprit?
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There’s no better feeling than when you’ve setup your system and turned it on to find it lacking any noise.

This is no major feat when you have control of the electrical distribution, but when you don’t, things can be a bit more dicey.

The classic scenario when the system powers up with a hum is for the operator to declare “ground loop!” followed by muttering and cursing while digging in the accessories box to locate the power cord cheaters. 

I find it funny how a device that’s supposed to be used to provide an electrical ground connection on older two-prong outlets is most often employed to lift the ground instead.

In such situations, you gotta do what you gotta do to safely eliminate these nuisances if possible. But I often see that the whole ethereal concept of a “ground loop” is a distraction from one big fact: not every hum comes from a ground loop.

What seems to be nearly universal is that a lot of folks don’t understand that the existence of a ground loop is not actually the cause of a ground loop hum. A ground loop is only a condition that is exploited by the true problem, which is an electrical current flowing through the loop.

Carefully designing a system to not have ground loops is a noble engineering endeavor. But in my book, there’s no real reason to do so if you take the time to eliminate the actual hum sources and potentials.

Treat the cause, not the symptom.

One job I worked in the past was on a sound system with a noise problem that historically couldn’t be solved.

This system was in a mid-sized church in a community known as the “Home of the Hardheaded Dutch.”

(You may accuse me of racial stereotyping, but believe me, this is how they referred to themselves. And they were proud of it.)

When we first walked into the sanctuary, the system was on and I immediately heard a significant buzz. The contractor turned to me and said, “Oh by the way, we’re going to solve their noise problem too.” Which was to say, “You need to fix this because I can’t.”

I hemmed and hawed about how the problem could be from the transformer on the pole, but was actually just making stuff up out of thin air, aggravated about having been surprised with this additional time-consuming task being added to my already conservatively budgeted schedule.

The church elder and de facto tech director we were working with was a retired Master Chief named Dave. He knew diddly-squat about sound systems, but possessed a good nose for BS. I could tell he wasn’t buying mine.

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