To Surround or not to Surround
Jun 1, 2002 12:00 PM, Linda Gedemer
SURROUND SOUND systems; they're everywhere. What started out as a great way to enhance the movie-going experience has branched into almost every conceivable form of entertainment. There are 5.1 home theater setups, video games and live entertainment, and if you're lucky enough to fly first class, you can even enjoy phantom surround sound in those nifty little headsets on the plane.
Everyone wants it. I wish I had a dollar for every time one of my corporate clients turned to me and said, “I have a surround system in my living room. Can we do that here in our executive board room?” Needless to say, there are about a hundred good reasons to talk your corporate clients out of a surround-sound system in their conference rooms. PowerPoint presentations in 5.1 surround? Scary.
Instead let's look at surround in retail and entertainment environments. (As a woman, retail and entertainment go hand in hand for me. Men, bear with me.) When one of my retail or entertainment clients comes to me asking for a surround system, my first reaction is to figure out a way to provide them with it. But should I?
Careful consideration has to be given to why your client wants it and what they're going to do with it. Maybe this sounds like a no brainer; surround is ideal in many other forms of entertainment, so why not retail venues? Surround sound is quickly becoming the accepted norm for audio playback. Some end users are starting to believe that the entertainment experience is reduced if there is no surround system. But that shouldn't push designers and installers to put surround everywhere there is an entertainment element.
Think of a background music system in stereo, and you'll start to see my point. Surround is great, but its use and ultimate success depends on defining the parameters of the system, applying it to the right applications and designing and installing it correctly.
STEPS IN DECIDING
one of the steps is to consider what purpose the venue will serve. Is it to entertain, inform, educate, attract (shoppers or gamblers) or all of the above? Can a surround system aid your client in getting their message across, or will it simply create problems?
Also consider whether the physical space lends itself to a successful surround installation. Carefully review all aspects of the room's acoustics and speaker placement options. Effective surround depends on those factors. Also, think about what products can aid in design when the acoustics and speakers placements are less than perfect.
Finally, what type of surround is the client looking for? When people think of surround, it's not always in the context of a standard 5.1 system. I have had clients use the term surround sound when what they were really looking for was an immersive audio system to create soundscapes using a multichannel audio system. The important distinction between the two is that standard 5.1 relies on finely tuned acoustics, particular speaker placement and tailored audio tracks to provide specific spatial cues. Immersive audio simply provides a sense of spatiality and does not rely as closely on acoustics, speaker placement and specialized audio tracks.
- Considerations in the Retail Context. Here are the initial ideas put into terms of retail venues. Retail venues are having an identity crisis, caught somewhere between selling a product and becoming an entertainment venue to attract shoppers. Retail owners want ways to bring more people into their shops, adding projection screens, videowalls and so on.I came across an interesting example in my local mall at a popular children's store. A videowall and accompanying stereo system were playing the company's latest video release. Few people were shopping; most were sitting on the floor watching the video. The sales people must have been pulling their hair out. Naturally, I questioned the success of that particular installation. Sure, it brought quite a few people into the shop, but they weren't spending any money.Another example came from a friend of mine who had developed the A/V systems for a large athletic shoe chain. The company's design directive was to create minitheaters within the stores. Not only did the displays cause foot traffic problems within the stores, but the effect of the expensive surround system was lost due to crowd noise, the harsh acoustics of the space and an audience that constantly moved in and out of the surround sweet spot.
- Some Possible Uses. This isn't to say that surround should never be placed in a retail venue. A successful installation can be had as long as issues such as traffic flow, ambient noise, acoustics and the client's expectations are considered. In some cases, retail environments would be better served by unique video displays augmented by immersive audio systems that give the shopper an entertaining background to their shopping experience. The emphasis is on background.Another option is to set up a small theater with a surround system that is out of the way of traffic patterns in the store. This theater could be designed with all the characteristics of a real theater in mind, including acoustics and proper speaker placement. The theater would provide guests with a place to rest their feet and sit for a minute to watch the company's latest add campaign.Keeping the show cycle short ensures that the shopper will not stay parked inside the theater all day. I know that retailers don't like to give up valuable retail space for non-retail purposes, but some stores devote a great deal of space to display devices. I'm not suggesting that retail clients should be talked out of their surround system; instead, they should be presented with options to use multichannel audio to attract rather than to distract.
- Surround in Entertainment. For entertainment venues such as theme parks, true surround sound systems can be easier to implement and can be quite successful. Some of the most popular attractions at theme parks today are simulator rides and 3-D theaters, both of which rely heavily on surround sound. These are purpose-built theaters in which architecture, acoustics, set design and audio systems have all been designed to work hand-in-hand. You also have a willingly captive, stationary audience that is there to enjoy a rich sensory experience. This is where surround sound can be most effective. Consider that these attractions mimic movie theater design, which surround sound was initially intended for.
Not all themed environments lend themselves to surround, however. Surround was developed for a theater-like environment and has a specific sweet spot. Once an attraction design starts to pull away from a typical movie theater shape, then the ability to successfully implement surround sound can become quite difficult. Examples would be moving rides and attractions with odd room geometries, difficult acoustics or interior designs that do not allow proper loudspeaker placement. Creating an effective surround system in these types of attractions is not impossible, but once again, they might be better served by a nonstandard surround system.
SURROUND DESIGN TOOLS
let's consider some tools available for the design and implementation of various systems. Most people are familiar with a standard 5.1 surround system setup. Today, numerous 5.1 decoders and speaker systems are available, and their use is well documented. Augmented surround systems, or those that use additional channels beyond 5.1, can be created using a multichannel playback device connected directly to a standard processing unit and a host of amplifiers and speakers. In that case a surround decoder would be optional. Some systems use a 5.1 decoder with additional devices. An example of that type of system would be a 7.1 system incorporating traditional surround channels with the addition of a rear and overhead channel. Those systems have been used successfully in theme parks.
A few years ago I helped develop such a system in a simulator ride theater. A rear channel was required so that the sound would augment the ride backing up and “crashing” into the wall behind it. I used two DTS decoders with the incoming control signal split between the two so that sync was not an issue. The first decoder contained the standard 5.1 track configuration, and the second decoder had the rear channel information with enough tracks left over to add additional audio in the future and to record SMPTE to one of the channels. The SMPTE channel was used to send control information to the other devices in the show such as the simulator ride and lighting controllers. In this way the film projector and DTS units became the master controller. This system was easy to implement and worked quite well.
- Immersive Audio Systems. Immersive audio can be designed in much the same way as nonstandard surround systems. A multichannel playback device can be connected to the necessary processors, amplifiers and so on. The main difference between an immersive system and a standard surround system is that the former does not always need to by synced to a video. If both the video and sound exist simply to create an environmental effect, then the two systems only have to be given a start trigger at the opening of the attraction and left to run freely for the rest of the day. In immersive systems that give audio the illusion of moving around the room, the same multichannel playback device need only be run through an externally controlled matrix, and various triggers can be set up in programming. That would save the soundtrack producer the trouble of having to create the illusion when producing the audio tracks themselves, and it allows the system to be changed at will. Level Control Systems and Peavey Media Matrix make useful processors that are ideal for this effect.
- Acoustic Enhancement. Another option for creating immersive audio is to use acoustic enhancement devices such as the Lexicon LARES system. Steve Barbar of Lexicon has an excellent example of this device's use in a themed entertainment space. An entertainment venue created a cave that needed the ambience of a real cave. Unfortunately, the cave was created of fiberglass rockwork. Needless to say, the natural acoustic properties of the cave did not lend themselves to creating a realistic environment. The LARES provided enhanced acoustic properties to the audio track.
- More Tools. I mentioned some potentially difficult acoustic environments in retail and entertainment spaces. Although it's not impossible to create true surround in those environments, the designer will have to look beyond off-the-shelf systems. Devices available for working in less-than-perfect conditions include digital signal processing-based loudspeakers and processors. DSP-based line-array speakers such as the Duran Audio Intellivox series provides the system integrator the ability to place speakers in difficult acoustic environments while allowing them to dynamically control the information directly aimed at the listener. This solution allows the integrator to control the electoacoustics in situations in which he or she cannot control the physical acoustics.
Duran Audio is one of the companies supported by CATT Acoustics, makers of acoustic modeling programs. CATT allows a room to be acoustically modeled and to have the parameters directly control the Intellivox speakers through DLL directivity interface modules. The CATT and Duran Web sites (netg.se/~catt and duran-audio.com) provide detailed explanations of the process.
Another way to overcome harsh acoustic environments is to control how much the speakers interact with the room's acoustics. That can be accomplished by simply bringing the speakers closer to the listener. An argument against this method might be the possibility of losing the ambient effect, but that can be overcome using digital reverb units.
With the use of DSP line arrays and close proximity speaker placements complemented with digital processors, designers can now look outside the box for an answer to traditional surround speaker placements that will not work in difficult environments. The products I've mentioned represent only a small sampling of what's available. It is wise to broaden your search for products and research devices that are not otherwise considered for these applications. Retail and themed environments vary widely in their designs, and systems integrators have to approach these projects with an open mind.
Linda Gedemer founded The Audio Group in 1992 as an A/V consulting practice and post-production studio. She has been recognized for her work in both system design and audio editing. Correspondence can be sent to The Audio Group firstname.lastname@example.org.
Virtual or Actual: How Will Sound Be Used?
Early on in any retail or entertainment project, you will need to determine whether the audio system (and associated visual system) will be helping to create a virtual environment or to re-create an actual environment. The reason is that the audience will be more forgiving of audio reproduction in a virtual environment, especially one that is not trying to simulate reality. That comes from the lack of prior cues and memories that an audience can compare the environment with.
When recreating an actual environment, the audience will be more critical of the audio playback experience. People will expect to hear information coming from very particular locations. Given that fact, immersive audio can — in general — better create a virtual environment while standard surround (or augmented surround) will better serve the recreation of an actual or simulated-reality environment. To Surround or not to Surround Some believe that the entertainment experience is reduced without surround. But that shouldn't push designers to put surround everywhere there's an entertainment element.