How to Create Good Sound Design in Open-Air Spaces

Author: Michelle Russell       

sound design

Audio technicians have may tools available to get good sound in a room, including directional speakers like the ones used at this Convening Leaders 2015 session. (Jacob Slaton)

Since its founding in 1979, Berkeley, California–based Meyer Sound has “been devoted to meeting the needs of sound-reinforcement professionals,” not only with products but through high-level technical education, according to the company’s website. Helping to realize that mission is Steve Bush, Meyer Sound’s senior technical support specialist and instructor in its audio education program. Company founder John Meyer, according to Bush, has made a name for himself by creating “unique and game-changing” products “that solve problems,” including pioneering a self-powered loudspeaker technology used at many live-concert venues today. The company has grown from producing loudspeakers to working on acoustic treatments and digital processing.

Convene asked Bush to draw on his 10 years of experience at Meyer Sound, as well as 20 years prior to that as a self-described “sound guy” who spent a lot of time in convention centers.

What can meeting planners do to improve intelligibility and sound in spaces divided by air walls?

It can be expensive, but if you know that [you] are in a specific convention center or even in a hotel where you’re dealing with the grand ballroom that divides into three, and you know that the air walls bleed, you can buy out the other sections. If you’re in Hall B, buy Hall A and Hall C as well, or try to schedule around competing events. Sound isolation is difficult in these types of rooms. If there are air leaks — and there are usually large gaps at the ends of the air walls and small ones between the panels — there will be sound leakage.

sound design

“Good Sound Can Happen Everywhere Today” — Steve Bush

How can planners assess whether there will be sound issues in rooms they are considering for events?

There are some basic tests. If you go into several rooms and just simply say “hey” loudly, and then clap your hands once, then have somebody go to the other end of the room and do the same. Listen closely to what happens right after the initial sound. You can start to build this library of how rooms sound after you put speakers in them and it sounds good, and how rooms sound after you put speakers in them and it sounds bad.

There are two characteristics to listen for. There are these echoes — “hey, hey, hey,” like in a canyon — or there is reverberation, which is the continuation of a lot of little echoes so close together that you don’t actually hear them as individuals. That’s all reverberation is — a large number of very closely spaced echoes — but our brain doesn’t hear them as independent things. It just turns into a long decay, like the sound in a cathedral. Long echoes are really problematic for speech, hearing everything twice or more. Reverberation is problematic for intelligibility as well, muddling speech.

There’s an understanding of what happens in a room with reverberation and echoes, and when they become detrimental to speech intelligibility. As soon as we put loudspeakers in a room, [they] can really help if they’re directional enough not to create a lot of sound at the surfaces, at the walls and ceiling. So even in a problematic room, if a loudspeaker can just make noise for the audience — and, just as importantly, not make noise where the walls are — you would be less concerned with the echoes and reverberation.

There are some different approaches to pull this off. We can distribute loudspeakers through an audience area, either under seats or pendant-mount them from the ceiling like in a cathedral, and get the speakers closer to the listeners so they don’t have to be very loud, and they make less energy at the surfaces — less reverberation.

We have directional speakers that can be electronically steered. There are small-line arrays, there are point-source speakers — and as I say to my classes all the time, it’s really a matter of picking the right speaker, putting it in the right places, and pointing it in the right direction. Most of the time, speakers on stands are not ideal. Suspending them from a truss or the ceiling and pointing them down onto the audience reduces the amount of sound likely to arrive at a surface, which reduces reflections and echoes.

Changing the reflective surfaces can be beneficial. It increases voice intelligibility. Heavy theatrical drapery is an option for temporary use. It can be hung along a wall from a piece of truss. If you can cover up even half of the wall with a length of drape that’s twice the length of the portion of wall being covered, and stand it off the wall by about a foot, you can decrease the reverberation and echoes in a room.

Is the science of sound something most hotel AV companies are knowledgeable about, in your experience?

There’s a lot of variation in quality out there. Some sound folks are more interested in mixing — more the art side of sound than the science side of sound, so they’re less interested in where they put the speakers, what speakers they’re using, or how to get those speakers to work well together. Additionally, hotel AV companies don’t always have a good loudspeaker inventory to pull from that matches the needs of their rooms.

Sometimes it’s good to hire [an outside] consultant or a technical director who understands the technical principles behind these issues. I used to get hired to come in and do big [conferences]. As the master audio guy, I never stepped behind a console. My job was to make sure that the right systems were specified and implemented well and [that] the operating staff had all the information they needed.

How would a meeting organizer find such an audio expert?

Unfortunately, there’s no reliable database of qualified audio professionals. So by title, you may be looking for a system technician, most likely from the concert world. Most of these people are freelancers. Look for referrals or use LinkedIn and Facebook.

It’s a little bit of a challenge, because most venues present themselves as having sufficient in-house sound expertise.

An audio representative working for the event, not the “house,” should be involved early on in the project to do a site survey well before load-in. Most of the time, a good, experienced sound crew knows what the solutions are, but by the time load-in has started, it’s too late to implement anything that would substantially improve the outcome.

With the right equipment and the right kind of acoustic environment, these professionals can do magic. If the equipment is lacking or the acoustic space is not conducive, the sound technicians are dealing [with a losing proposition]. It’s really frustrating for everyone when half the room can’t understand what the keynote speaker is saying — more so for the people who are responsible for making it sound good.

Michelle Russell is Convene Editor in Chief.

Sound Bites

Steve Bush’s tips for good sound design in open-air learning environments:

Scale down

“One easy solution is never to have two areas going next to each other. In some situations, you may get better results if you eliminate loudspeakers completely. In some way or another, avoid using one or two big loudspeakers, but instead use small loudspeakers and place them close to the listeners — overhead or under the seat in front of them.”

Consider headphones

“[There are] hearing-assistance systems; if you go to the theater and go to the hearing-impaired desk, they’ll give you a little receiver and some earbuds. [In an open-air environment], you could move from one area to another, change the channel, and hear each presenter very, very well. Having something in your ears for some people is not that great, but it does two things: It gets the speaker in your ears, and it also blocks out most of the other noise. Wired headphones are a little problematic only because you have to manage wire routed to all attendee locations, and the locations become static. But, in some ways, they’re easier to install than speakers, there’s no rigging, and there are no speakers to get in the way of the video screens and lighting rig.”

Don’t settle

“In the audio world, there are lots of things that can be done — creative, fun, and interesting things. Sometimes they’re a little bit more expensive, and you have to weigh the benefit with the cost, but sound problems don’t need to happen anymore. There are really no excuses these days. We have the knowledge, and we have the tools. We have really good loudspeakers. We have acoustic-treatment materials. We have experience. Even in rooms that inherently have horrible acoustic problems, we can solve them pretty easily. Good sound can happen everywhere today.”

Listen Up

That open-air room set is murder on your attendees’ concentration. Your keynoter’s voice is getting lost in the cavernous depths of the theater space. And the music at your cocktail reception is way too loud. But don’t worry — good sound design is as easy as listening to the audiology experts, meeting organizers, and AV professionals we’ve assembled.

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