Get Better at Troubleshooting Live Sound Issues
In a perfect world, the gear we use doesn’t break down, people make no mistakes, the weather is always agreeable and time is in abundance. Sadly, we do not live in a perfect world. Simple math shows that the more shows you work on, the higher the chance of encountering problems that need to be solved. One of the most important qualities of a great sound engineer is not only trying to prevent the issues from happening, but also how quickly and efficiently they can resolve problems. Although most of them usually have a simple solution, the main factor of success is how quickly one can pinpoint the exact piece of gear or the exact situation that is causing the headache. Learning to be a troubleshooting ninja takes time and experience, but can also be acquired more swiftly when keeping in mind some of the following points.
Signal Flow Interruption
Photo: Marko Alpner
One of the issues you might encounter in the live audio world is the absence of sound. You have connected everything, the artist is performing, but you see no signal on your console or hear nothing from the speakers. One of the easiest ways to determine the issue is to follow the signal flow and check its presence at multiple locations down a path to the speaker. On a typical digital console, if a vocal microphone is not working, you can start with the microphone itself, changing it to see if it is working properly on another channel, followed by checking the microphone cable, the multicore input and cable, the stagebox input, the digital signal carrier to the console, the input patch on the console, the preamp setting, the mute button and mute group assignment, the fader and any fader bus assignment, master fader, main out patch, stagebox output, the amp input signal cable, the speaker amp setting and patch, the speaker cable and the speaker itself. All these points can be the answer to why there is no sound and knowing how the signal flows is the only way you can trace the sound in its acoustic, electrical or digital form to the point of failure and fix it. In today’s world, where sound systems are very complex, you may also need to have some knowledge of IT network settings or various digital protocols, but it all comes down to the fact that signal flow is the basis of all that detective work.
Play the Numbers Game
If we had to check all that signal flow for every channel and would have to trace all those points throughout the signal path, we would not be very efficient or fast. So knowing what your most common points of failure are can be extremely helpful in cutting down the time needed to resolve issues. Taking the previous example of a vocal microphone signal path - if there is no sound coming from that line, there are a few simple rules to keep in mind when troubleshooting the system:
What have I already checked and am certain it is working?
If you know your outputs from the console are working correctly because you have already played some material through the speakers, you can eliminate the search from the output section of the console onward. If you did a line check before the show from the stagebox, you can focus on finding the solution on the stage. If I know a microphone is working by testing it on another line or channel, then it must be the cabling. The narrower you can get the search field, the quicker you can figure out the issue.
Usually it is human error, not the gear
Although instruments, cables, and other audio equipment can get broken during their touring life, it is much more common that an issue is caused by human error. Incorrect patching, inglorious results of miscommunication, gear not turned on - you would be surprised how many times those things happen even to the most professional crews. After all, the conditions in which we work and the time constraints put on us are really stressful and can cause momentary drops in concentration, which can then lead to gear not working properly. These are the first things to check when something unexpected happens - cable patches, DI box switches, power buttons, power lines - everything a human being was responsible for connecting, switching on or powering.
Prioritizing Gear Search
Only after you have eliminated all possible human error issues should you go and research the pieces of equipment on stage. These should be prioritized, starting with the things that are most likely to get broken. If we once again take into consideration the vocal microphone chain, it is much more likely that the faulty piece of equipment will be a broken cable than the microphone itself. It is also much more likely that the fault lies in the cable that connects the stagebox to the console than whatever piece of gear it is connected to on either end. Keeping that in mind, you can become really fast in determining what the issue is and how to fix it.
Learn the Sounds
I remember a show I was working on as a monitoring engineer. During the changeover between bands I did my pre-show routine, where I also checked if all my wireless system frequencies were still interference-free. I did that with my bodypack in engineer mode, since it is the fastest way of doing the task and right off the bat I heard a noise on my first frequency. I switched over to the second one, and there was that noise again. But it was not a noise I recognised. It sounded nothing like interference, with its distinct high frequency “swish”. The noise was more similar to the sound of radio static or digital crackling. So instead of hastily redoing my frequency coordination, I changed my bodypack, and voila - the noise was gone. After the show we figured out that the bodypack itself got broken and was causing those noises, but it was the ability to distinguish between noises that saved me from chasing my own tail and possibly delaying the start of the show. I got to that point by always asking “What was that noise?” on every issue during every soundcheck we had. The ability to discern the noise of a broken cable from the noise of a bass guitar string being slapped to the coil can be a lifesaver, and knowing how a digital sync issue sounds different from an unmuted SMPTE channel is crucial. We are always on the lookout for unwanted noises from our gear, but when they happen, you should remember how they sounded and also what was done to eliminate them.
Anticipate Issues
This will probably go against every optimist fiber in your being, but it sometimes helps to anticipate what can go wrong during a show. If you know the only thing that changed in the microphone setup for a 50-piece symphony orchestra from soundcheck were the clip-on mics for the double basses, then if something is popping or buzzing when they are setting up for the show, you bet I am looking at those channels first, before I start exploring the other 60 inputs. Everything that is being changed between two bands on stage is more likely to be the issue than the static microphones or lines. I admit, there are many more ways of something happening than we can anticipate, but at least the most obvious ones can be determined beforehand. Although we should do everything we can to prevent issues from happening, sometimes preventative measures are out of our hands- that is when anticipating where the issues can happen can be very effective in reducing our response times.
Learn from Others
As a final suggestion I recommend doing something that is in our blood anyways, and that is sharing stories from the road with our colleagues. It is tradition that any lengthier conversation between two audio heads will veer off towards talking about audio gear and then about shows you did. On that second topic, we can quite often discuss the “horror shows”, where our skills, patience, or usually both were severely tested. I love listening to those stories, not only because of the bonding moment, but also because I find it extremely valuable to listen to what happened to others, what was the issue and how it got fixed. It is something I try to remember for my own future experience, because that same thing can one day happen on my show. Knowing how to respond or even just remembering who to call that had the same issue for troubleshooting tips can be extremely helpful.
Photo: Marko Alpner
In addition to all these tips, it really helps to get some vital pieces of gear that can help you in your detective work. I have already talked about the Sound Bullet, my weapon of choice for such work. But even if you do not go for the swiss army knife of audio engineers, a cable tester, a multimeter, a signal sniffer or phantom power checker should be on your list of things that always live in your backpack, just because they can prove to be instrumental in saving the day and putting a derailed sound check or show back on its tracks.
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