Channel Problems?
You might have channel problems on the board. A quick way to test this is by swapping the input cable from that channel into a different channel that’s functioning correctly.
Also, be aware of any rack equipment you have plugged into a specific channel. These could be compressors or effects units, for example. Unplug those to remove them from the signal chain and listen for the buzz to go away.
What If It’s Not Channel Related?
The good news is buzz that appears today that wasn’t their yesterday, is probably channel-related. The reason is moving parts.
For example, plugging in a guitar cable puts wear and tear on the components. The more wear and tear, the more likely to wear out. That being said, all equipment eventually fails.
Buzz coming out of the system, which isn’t created before it enters the mixer, means you likely have equipment failure of the expensive nature. Yeah, sorry about that. It’s possible a cable has gone bad or equipment was bumped which pulled out a plug part-way. But, well, ummm, one can only hope it’s that cheap and easy.
Back To Finding The Source
Tracing the signal flow for a simple setup, the sound goes from the mixer into a house EQ then into a limiter then into the amplifier and then out to the loudspeakers. Cross your fingers, say a prayer, and start by checking all cables are properly seated in the signal path. Turn off the power before you start re-seating cables.
From here, start swapping cables. Of course, make sure everything is turned off before you do anything.
You are a bit limited in what equipment you can swap unless you have spares of everything or can pull from another system. Consider bypassing the house EQ and then the limiter. I’d bet dollars-to-doughnuts that the problems won’t go away and that it’s in the mixer, but you just never know.
Also, I have never bet dollars-to-doughnuts because I’m not usually flush with doughnuts.
Equipment Repairs
There are obviously many ways equipment and cables can fail. There are two questions you must then ask yourself:
—Do we fix it or replace it?
—Where will we find the money?
Regarding the second question, I could easily spin off into talking about budgets but I’ll keep it short with these few bits for your consideration;
You should have an annual budget which accounts for possible equipment replacement. Don’t worry about a total cost replacement but a 30 to 50 percent replacement amount would be good.
Your audio budget should include a plan for general replacements/upgrades. For example, in five years, when you plan on upgrading the loudspeakers, you’ll want to have already set aside the money.
Fixing versus replacing isn’t a question of which is cheaper, it’s a question of what makes more sense. For example, if it would cost $500 to fix your $1,000 mixer, it might be the time to go ahead and get that mixer upgrade you’ve wanted.
However, if it only costs $150 to fix it, then just fix it. Cables can be replaced or repaired at little cost. Do what makes sense. As well as being the person in control of the audio system, you are also to be a good steward of money.
The Take Away
Audio buzz usually comes from only a handful of places like; equipment, instruments, and cables. The key to tracking down the source of the buzz is identifying the output and the general source. Then, narrow that focus and find the specific source. It’s detective work and you have to follow the clues.
Finally, signal-related problems such as this are covered in the Line Check chapter in my Audio Essentials for Church Sound guide. You can learn how to quickly diagnose and resolve signal problems.
Ready to learn and laugh? Chris Huff writes about the world of church audio at Behind The Mixer. He covers everything from audio fundamentals to dealing with musicians. He can even tell you the signs the sound guy is having a mental breakdown.