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In the first of a two-part series on surround sound audio, Post is taking an in-depth look at the often overlooked topic of mixing surround sound for commercials. Even though sur- round sound for commercials has been used for well over 10 years, finding practical information on the ever-changing formats, practices and requirements for commercials mixed in 5.1 can be difficult. As common as 5.1 is, commercials mixed in surround sound lack sufficient audio standards and are subject to a multitude of variables. Some of those variables are based on personal preferences while many others are based on the lack of, and sometimes conflicting, standards for broadcast commercials. By coincidence, this month’s audio feature is a tale of two cities,New York City and Los Angeles. It is a story of two opposing workflows that just hap- pen to be on opposite ends of the country.The key difference is that one starts with the stereo mix first and the other starts with the 5.1 mix. AUDIOENGINE Tom Goldblatt, partner/mixer/sound designer at AudioEngine (www.audioengine.net) in New York City gives us his in-depth view on how a commer- cial is mixed in both stereo and 5.1 simultaneously. With credits such as Calvin Klein, Amstel Light and Mountain Dew, he knows how integral the stereo mix is to the workflow of mixing commercials in surround sound.The stereo mix is so crucial to the post production process that the stereo mix is made before the 5.1 mix. Once the stereo mix is completed and approved, it becomes the blueprint for the 5.1 surround mix used for broadcast. Gold- blatt must ensure that when the mix is broadcast on air, the down- mix matches the true stereo mix made during the approval process. This workflow may seem a little backwards, but the reality of how commercials are produced, approved and ultimately heard by the consumer is precisely why he chooses to work in a seemingly coun- terintuitive way.“This is actually the big discussion right now,” explains Goldblatt.“With the commercial world the way it is with the budgets and time constraints, the focus is still on the stereo mix.That’s why I make the stereo mix first.Then the surround sound 5.1 mix is derived from the elements of the stereo mix.Now of course, this is the oppo- site of how the film world and how broadcast TV works.” Goldblatt is faced with many requirements for a commercial broadcast, including single-thread delivery.“The reality is that if you are doing a 5.1 mix for a commercial, a stereo mix would never get used for broadcast,” he says. “People listening in their homes in stereo would be listening to the downmix of the 5.1, not the true stereo mix I made separately.That’s why I must be certain that my 5.1 surround mix matches the approved stereo mix when it is downmixed during the broadcast.” The other challenging part of doing surround for commercials for Goldblatt is that the 5.1 mix has the least amount of time spent on it during the session, he says. “Surprisingly, it’s a minor part of the session at this point. Most of the time is spent on sound design, edit- ing and mixing for approval in stereo. In commercials, everything is approved by the stereo mix because many times the people who are approving the mix are not in my studio with me at the time of the final mix. Also, single-thread delivery is the way of life right now, and that is why I must ensure that the 5.1 mix is going to downmix to reproduce the stereo mix done for approval.The stereo mix is what clients have heard and are expecting to hear on air.” Stereo is still likely to be heard in most people’s homes, including homes that have a home theater system.A home theater household will typically have only one main viewing area with the home theater system. Often, any additional televisions located in that same house- hold are not likely to be set up for 5.1 surround sound. Many people have televisions located in the kitchen and the bedroom in addition to their main viewing area.“Let’s face it, most people are still not lis- tening to 5.1 in the home right now,” says Goldblatt.“So, 5.1 is still a small percentage of the entire viewing audience, even with house- holds that have a home theater.” Surprisingly, 5.1 surround sound for commercials is not as wide- This 5.1 Motorola spot, out of Anomaly, premiered during the Super Bowl. AudioEngine’s Tom Goldblatt took full advantage of the LFE channel. spread as initially predicted years ago.That makes the process of folding down a 5.1 mix to stereo even more important. Goldblatt uses several different techniques and accounts for as many variables as he can.“I check the downmix through several different methods. I use Pro Tools to fold it down through the bussing from 5.1 to two with plug-ins. In the true film sense, I will also use the Dolby 563 and the 564 for monitoring the Lt/Rt mix.That’s because many of the consumer systems are still using Pro Logic 1.” Complications can arise from the variables in the home, variation on broadcast spec and each mixer’s personal preference with how they like to work. Since the bulk of what Goldblatt mixes in sur- round is commercials, his techniques and preferences have been shaped by what is best for the stereo downmix when broadcast. For example, surround sound mixing may or may not involve using di- vergence, depending on personal experience. “I don’t use divergence on the center channel,” he explains.“That is not a personal preference as much as it is being worried about the fold down.With the center channel, I am not really a fan of spreading out the dialogue into the left and right channels for a 5.1 mix. I be- lieve that the dialogue should be anchored in the center. Even with the announcer, I anchor it down in the center channel because other- wise you could get a build up of the levels when folding down.And with consumer set-ups in the home, who knows where the left and right speakers are going to be? They could be placed in any number of places, unlike a movie theater where the front left and right speak- ers are always set up behind the screen appropriately.” In a typical surround mix, divergence is not only an option for the center channel, but also the front and rear speakers.This is also a preference that varies with each project.“It depends on the ma- terial,” says Goldblatt.“I will do a front to rear divergence on music www.postmagazine.com October 2010 • Post 35