In Defense of Live Sound Engineers

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Image by Flickr user Ville Hyvönen. Licensed for free commerical use through Creative Commons.

Image by Flickr user Ville Hyvönen.

I would suspect that all of us have been to a concert and have experienced less-than-stellar sound.

I know that this happens quite a bit because concertgoers are quick to point it out:

“Dude! Did you go to the show?”

“Yeah, it was killer but it sounded awful. The sound guy had no idea what he was doing. They should hire a new one.”

There used to be a running joke amongst sound techs: Everybody knows two things: Their job, and sound.

This sentiment is often borne out of the need that some audience members feel to offer detailed advice to the band’s mixer during the show, or immediately afterwards, so that perhaps, this poor, unqualified soundperson will figure out how to do his or her job properly before the next show.

This is especially interesting, because no audience member ever seems to give the lighting guy notes during or after the show.

Having been a live sound engineer for many years (though not anymore) I understand the challenges that every music venue present to both the mixer and the band. So before offering your expert advice to the soundperson at the next concert you go to, make sure that you have considered some of the factors that contribute to a bad-sounding show. As they say: “Don’t judge a man until you’ve walked a mile in his shoes…”

I offer these complicating factors that impact the sound of many shows in no particular order:

1. Bad Room Acoustics

When I was a FOH system tech, I was always surprised when a visiting touring mixer would comment on how bad the acoustics in a particular arena were. “Of course it has crappy acoustics; it’s a hockey arena”, I would think.

Very few large venues are purpose-built for live, amplified music performance. This is especially true for big touring acts that are playing in arenas that were designed for basketball or hockey. These buildings are built to allow as many people as possible to have a good view of the court or rink without regard for the acoustic performance of the building.

While many venues do address the acoustic design and do what they can to make the room sound better, that is not the primary focus of the building designer. These are cavernous, mostly-empty structures, often with reverb times well over 3 seconds long. These are not positive attributes for a music venue.

Because of this, the most obvious contributor to bad concert sound is often the acoustic signature of the venue, or in other words, the sound of the room.

Every venue has “a sound”, and just like any other enclosed space, the sound changes as you move around the room. For example: the third row in the center of the house sounds different than the ninth row in the balcony, house left. This is dictated by the immutable laws of physics, so there’s no way to eliminate this effect. Even a great band with the newest sound system operated by the most qualified techs will still be governed by this reality.

To try and minimize the effects of this phenomenon, modern PA systems are designed to deliver a consistent, predictable coverage pattern with a balanced frequency response throughout their coverage area. Sound system designers also take care to make sure that the speakers are aimed at the audience and not aimed at the sidewalls or the ceiling. This reduces the level of the audible reflections from these flat surfaces so their effects are not as noticeable. But even with all of this attention and care, the sound of the band’s mix may still be fraught with nonlinearities in a concert setting.

These nonlinearities are magnified by the fact that the sound coming from the stage and the sound coming from the PA interact with the room in different and unrelated ways, yet they both contribute to the quality of the mix as it is perceived by the audience. (More on that in m moment.)

Mix decisions are usually made from the FOH mix position, and since the mix position is stationary, the mixer is effectively mixing for that position, and not for the whole room. What makes sense at the console may not make sense at your spot in the venue.

At some shows, you may observe a sound tech walking around the room during the performance to hear how the mix is translating to other parts of the room. Making mental notes about how the sound changes in different parts of the venue allows the mixer to make relative adjustments that are better for the audience as a whole. This is helpful, to be sure, but it doesn’t really account for the entire audience. While this at least shows a level of concern for consistent sound it doesn’t mean that the mixer can deliver the same exact sound quality to every seat in the house. It’s just not possible.

Sometimes, the mix that sounds terrible in your position may sound excellent elsewhere in the room. You poor sonic experience could have a lot more to do with the unlucky seat you picked in the room, and a lot less to do with the skill or performance of the FOH mixer.

2. Excessive Stage Volume

This can be an absolute mix killer and usually leads to a painful concert experience for the audience—especially those who happen to be closest to the PA. The mixer has few options available to solve the problem of excessive stage volume.

He or she can either have the band turn down (good luck with that) or can turn the PA up. The mixer could leave the loudest instruments out of the PA and let them blend naturally in the room with the rest of the mix. But this creates a different kind of problem: This method often creates a disjointed or incoherent mix, since part of the mix is present and clear (the stuff in the PA) and the rest of the mix is more ambient and distant. The relative perspectives of the various instruments in the mix just don’t add up.

This is not good for the audience, the mixer, or the band (who really want to sound like they do on the record). And keep in mind that in larger concerts, it’s often the band that signs the sound tech’s paycheck!

This problem can be even worse in theaters. If you consider that a theatre, which is designed for theatrical plays and live acoustic music, is usually built in such a way that sound projection from the stage is enhanced, it would stand to reason that something that is already loud to begin with, like a guitar amp or drum kit, could get out of hand very quickly.

I have been in situations like this, where the simplest solution is to only put the vocals in the PA to start, and then slowly add what you can as the show progresses—maybe a hint of kick drum to add some low frequency support; or perhaps an acoustic guitar or the keyboards since they don’t often have much amplification on stage.

This again may lead to a tonally disjointed-sounding mix, which is not the best light in which to present the band. And the audience has little choice other than to think that the mixer must not know how to mix! Not exactly fair, is it?

3. Excessive Room Reverberation

“Reverb” is the phenomenon that occurs when sound waves bounce off all of the reflective surfaces in a room multiple times. These reflections mix with each other and create a (usually) steady decay over time that can be expressed as the reverb time, which is also notated in RT60— a number that defines how long the reverb decay takes to drop in volume by by 60 dB. (For example an RT60 of 3 seconds means that once the original signal ends it will take 3 seconds for the reverb of that original signal to fade away by 60 decibels.)

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