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The author plying the trade at the monitor position. (Photo Credit: Marko Alpner)

In The Moment: Getting Better At Troubleshooting Live Sound Problems

One of the most important qualities of great sound engineers is not only trying to prevent issues from happening, but also how quickly and efficiently they can resolve problems.

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 that world.

Simple math shows that the more shows you work, the higher the chances of encountering problems that need to be solved. One of the most important qualities of great sound engineers is not only trying to prevent the issues from happening, but also how quickly and efficiently they can resolve problems.

Although most problems 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 the following points.

Signal Flow Interruption

You’ve connected everything, the artist is performing, but there’s no signal in the console or no sound is emanating from the loudspeakers. 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 loudspeakers.

For example, when using a typical digital console, if a vocal microphone isn’t working, start with the mic itself, changing it to see if it’s working properly on another channel. This is followed by checking the mic 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 loudspeaker cable and the loudspeaker itself.

All these points can be the answer to why there’s no sound and knowing how the signal flows is the only way to trace the sound in its acoustic, electrical and 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

It’s not too efficient to check all that signal flow for every channel and trace all those points throughout the entire path, so knowing the most common points of failure 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’s 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 is working? If you know the outputs from the console are working correctly because you’ve already played some material through the loudspeakers, 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 you know a microphone is working by testing it on another line or channel, then it must be the cabling. The narrower the search field, the quicker you can figure out the issue.

Usually it’s human error, not the gear. Although instruments, cables, and other audio equipment can get broken during their touring life, it’s much more common that an issue is caused by human error. Incorrect patching, inglorious results of miscommunication, gear not turned on – it’s surprising how many times those things happen even with the most professional crews. However, 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.

Prioritize the search. Only after you’ve 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 mic chain, it’s much more likely that the faulty piece of equipment will be a broken cable than the mic itself. It’s also much more likely that the fault lies in the cable that connects the stagebox to the console than whatever piece of gear it’s connected to (on either end). Keep this in mind and you can be much faster in determining what the issue is and how to fix it.

Learn The Sounds

I remember a show where I was serving as the monitor engineer. During the changeover between bands, I did my pre-show routine, where I also checked if all the wireless system frequencies were still interference-free. I did that with my own bodypack in engineer mode since it’s 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 the noise again.

But it was not a noise I recognized. It sounded nothing like interference, with its distinct high-frequency “swish.” Rather, it was similar to the sound of radio static or digital crackling. So instead of hastily redoing the frequency coordination, I changed my bodypack, and voila – the noise was gone.

After the show we figured out that the bodypack itself was broken and was causing those noises, but it was the ability to distinguish between noises that saved me from chasing my 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’re always on the lookout for unwanted noises from the gear, but when they happen, we 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 mic setup for a 50-piece symphony orchestra that was in place at soundcheck were the clip-on mics for the double basses, if something is popping or buzzing when the musicians are setting up for the show, look at those channels first before exploring the other 60 inputs.

Further, everything that is changed between two bands on stage is more likely to be the issue than the static mics 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’s when anticipating where the issues can happen can be very effective in reducing our response time.

Learn From Others

Finally, I recommend doing something that’s in our blood anyway, and that’s sharing stories from the road with our colleagues. It’s tradition that any lengthier conversation between two audio techs will veer off towards talking about gear and then about shows they worked.

On that second topic, we quite often discuss the “horror shows” where our skills, patience, and 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 the actual issue was, and how it got fixed.

It’s something I try to remember for my own future experiences, because those same things can one day happen on my show. Knowing how to respond or even just remembering who to call for troubleshooting tips can be extremely helpful.

In addition to these tips, it really helps to get some vital pieces of gear that can help you in your detective work. A Sonnect Sound Bullet I-O audio tester is my weapon of choice for such work. But even if you don’t go for this “Swiss army knife” for audio techs, a cable tester, a multimeter, a signal sniffer and phantom power checker should be on your list of things that always live in your backpack. They can prove to be instrumental in helping to “save the day” and putting a derailed soundcheck or show back on its tracks.

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