We do our best to offer solutions to our clients challenges. Some challenges are more easily addressed than others, but we’ll always do our best to help in the way we feel most appropriate for getting the desired results. Today’s challenge may not be in an event setting, but finds its solution in territory well-traversed by event sound techs all over the world.
While taking a Saturday morning stroll through our beloved downtown Springfield, I noticed a few friends hard at work inside their local eatery which is opening a new store front in the coming months. I had yet to visit the space, although a while back I did loan them one of Headline’s many loading ramps to help them get some new kitchen equipment in the building, so I already feel an unjustified sense of accomplishment in helping the place get on its feet.
I popped in to say hello and received the full tour of the new digs. We talked about opening timelines, paint colors, signage placement, the history of the building, cool stuff they found in the basement and finally a little bit about some potential audio problems they were facing.
The building is long and skinny like those shotgun style homes that are all over New Orleans. The kitchen is in the back, a bar area in the middle and a fairly large, somewhat narrow dining room up front. A lot of the interior seems fairly original, or at the very least is from a renovation that was done many decades ago. Aesthetically it’s wonderful, but like many spaces of a similar period, an abundance of hard surfaces (think ceramic tile, concrete, plaster, etc) and parallel walls mean its a pretty lively space in terms of the way it sounds. Of course once you get some people (aka “water bags”) in there along with some additional furniture, decor and the like, you’ll see these reflections start to tame so this issue will largely solve itself. I am no acoustician, but I have learned that reflections aren’t inherently a bad thing. Yes, too many and you’ll start to lose intelligibility and the room will feel loud even with relatively little input, but a room that is void of acoustic reflections will feel unsettling and claustrophobic. The reflections in this room felt appropriate for its size and application (remember we’re talking about a restaurant, not a recording studio), so no big reason to worry.
The primary concern was where to place speakers for the background music system. This is the first brick and mortar operation for this small business and, of course, working in food service they've got plenty of things to spend their money on to give customers an excellent experience before dropping too much cash on a speaker system.
The go-to solution for a dining space such as this can be seen at nearly every restaurant you visit. Typically you’ll find a relatively large number of speakers distributed throughout the space mounted on the walls or ceiling. This works well because every diner, or listener, is not far from the nearest speaker, so the entire system can be run at a fairly low volume and still maintain decent coverage throughout the space. This requires buying a lot of speakers and amplifiers and pulling a lot of cable to hook it all up, which can add up to a significant cost depending on the quality of the listening experience you’re going for. A system such as this might be in the cards soon for my start-up friends, but for now, we need to figure out a solution that delivers acceptable results with minimal resources.
This is where we start looking to what we can learn from the live sound world. If you go to a concert or event of a decent size (music festival, large theatre, arena, stadium, grand ballroom, etc) you will likely notice speakers hanging above the stage. This is what we refer to as a “flown PA.” PA of course being the abbreviation for ye-olden-term “public address [system]” and flown referring to how it has been deployed, in this case, hanging in the air. The alternative to a flown PA would be a “ground stack.” This is what you’ll typically find in lower capacity situations—small theaters, clubs, wedding venues, street fairs. Ground stacks generally require fewer resources to deploy as you can do so without a structure from which to hang them by using speaker stands or literally stacking them on top of the stage, subwoofers, some scaffolding, etc. Some rooms and events simply lack the resources to fly the PA. Keep in mind I’m making some generalizations on what systems you will find in which venues and as usual nothing in life is certain, but for the most part this is my experience.
So given the time, space and resources available, why is it generally preferred to fly your PA? In a nutshell it comes down to the distance between the PA and the people in the venue or listening area. It should always be our goal as sound techs to give everyone in the room the same experience. We want all those present to hear the event as it was intended to be heard and come away with some warm fuzzies. Let’s say you have a venue that’s a flat floor with an audience area 50 feet wide by 100 feet deep. Your stage is 40’ wide and the PA is stacked on the downstage corners of the stage, standing approximately 7 feet tall. If your first audience member is standing 5 feet from the downstage edge and the last audience member is standing 80 feet from the downstage edge, you can bet that the sonic experience for those two attendees is going to be vastly different as there’s roughly 75 feet of difference in distance between those two sets of ears and the PA.
Here’s a quick and dirty model of two, 4-box deployments of d&b audiotechnik V8 line array modules in our hypothetical 50x100 venue, ground stacked at 7 feet off the floor.
The SPL modeling above is set to show a different shade for every 3dB change. You can see this deployment is loudest for those right in front of the speakers and drops off as you move away. This can be okay as people generally do expect at a concert for it to be louder down front, but perhaps not to this extreme. In this situation, the differences are substantial with roughly 18dB of level drop from the hottest spots up front to the back corners of the area.
Let’s take the same PA system that was previously ground stacked and fly it otherwise in the same position in the X & Y planes but hang it 30 feet above the ground and tip it down toward the audience.
As you can see, we’ve created a much more consistent listening experience across the room. The hot spots aren’t as, well, hot and the extreme opposite end of the venue is getting a fair bit more energy. Yes, we do lose a bit of max SPL (sound pressure level or “loudness”) in the flown model because the PA is farther from us all, but you could make the argument that the only people experiencing that increased SPL of the ground stack were the few people down front while most other areas of the room suffered greatly. Again, we want consistency across the listening area so everyone can have a good time. Also, from a mix-person perspective, you want to be able to operate your system knowing that it generally sounds the same throughout the room, otherwise you find yourself walking away from the console all night listening for issues you don’t hear at front-of house.
Why bring up this long winded explanation for my restaurateur friends that just need a cheap and easy way to play tunes for their patrons? Well, my answer to them for now is it doesn’t really matter what speakers you have but rather where you put them. If you’re on a tight budget, just get a halfway decent pair of bookshelf speakers or whatever you have lying around and put them high up, as close to the corners where the wall meets the ceiling as you can. You’ve now decreased the difference in distance between your closest and farthest listeners. To try this yourself, grab a bluetooth speaker and set it on the ground, coffee table or other low surface. Walk around the room and pay attention to the level in various areas. Now move that speaker up on to a high shelf or cabinet and walk through the same areas. My bet is you’ll notice greater sonic consistency throughout the area when the speaker is up high and find you can actually turn the speaker volume level down and still hear it well throughout the room.
