Troubleshooting
One of the most important things that you can learn as an audio engineer is your systems signal flow and how to identify a problem and fix it when it occurs. If you don’t already know, this process is called troubleshooting. When I first started volunteering at Cherry Hills, I had no idea what signal flow was or how to troubleshoot an issue when it arose. I would usually just aimlessly wander around from mic to console hoping things would work. Understanding the signal flow of your system is very important so that you can quickly troubleshoot an issue when it arises. Unfortunately these issues never happen at convenient times, and usually wait until about 5-10 minutes before service to manifest themselves.
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The first issue in troubleshooting is often the easiest step: identifying the problem. Once the problem has been identified, there are four common ways to troubleshoot a problem.
- Start at the beginning of the signal chain and work your way to the end of the signal chain.
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Start at the end and work your way to the beginning.
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Start in the middle and work your way to the beginning
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Start in the middle and work your way to the end
​As an example, if your band is utilizing monitor wedges or headphones/in-ear-monitors for the weekend services, and your acoustic guitar player says that they cannot hear their guitar in their monitors, you have a few places to start. First, before swapping cables out and getting stuck in the troubleshooting process, the most common solution to this problem that I have found is that they’re simply not turned up either on the source (instrument) or on their monitors (console). The first place I would start is by looking at my console and seeing if I am receiving any signal (the green LED lights near the faders would be lighting up). If they are, you could start at the acoustic guitar and ask, “What level is your volume set at?” Oftentimes, the issue can lay with the musician and your equipment is totally functional.
Once identifying that their volume is turned up (I’ve found anywhere from 70-90% is best for most guitars and systems I’ve worked with, but have done 100% and it hasn’t caused any damage to the instrument or the system), you then have to choose one of the previous four options, whichever seems most likely. You could proceed to see if the 1/4’’ instrument cable that goes from his guitar to the DI has gone bad. This can fail at the guitar by not being properly seated or losing connection there, or the cable could be bad. To test if the cable is bad, you simply take the cable out of the guitar and tap on it. This will usually result in a popping sound. If you are receiving the pop, the problem usually lies with the instrument. If you are not hearing the pop, you probably need to start testing your cables and equipment downline. This will be a problem with your gear.
In this case, you could continue down the signal chain. You could start by changing the 1/4’’ cable out for a new one (it’s always helpful to have spares). If when you change the cable out, the sound works, you’ve found your problem. If not, you continue down the signal chain/signal path this way until you have isolated your problem. Using the above-mentioned methods, you will oftentimes be able to quickly isolate and address the problem so that your service can continue.
Unfortunately, the major problems that require you to know a little about troubleshooting will oftentimes never happen when you have time to address them at your own pace. At Cherry Hills, I can’t even begin to count the times that we had things go bad as the band was rehearsing or 10 minutes before service. One time, we had a guitar amp fail 10 minutes before service and had to swap it out with one that we had laying around backstage. It was just a miracle we found it, and more of one that we got everything set up and working before service started, but that oftentimes is the environment that comes when troubleshooting issues in a live setting.
