High-definition television is taking hold after years of fits and starts and format skirmishes. Channels are continually being added, and television set prices are falling. For us audio professionals, it means that supplying high-quality audio content accompanying HD television is becoming both a reality and a necessity.
The earliest adopters and experimenters in hi-def broadcasting were live concert recording (sometimes for DVD) and sports programming, beginning back in the mid-'90s. Much of the press at the time focused on the use of 5.1 channels and technical explanations of how to move the tracks around. I would like to focus on an often-forgotten area that can greatly affect the perception of “high definition,” whether in a live concert recording or sports programming environment.
Recording and mixing high-definition surround audio requires unusual attention to what defines “space” in a recording and how best to represent it. Approaching a recording with this in mind has immediate advantages in improving the sense of high definition in a way that technical specifications and discussions cannot.
As one begins setup for recording in a location, starting early allows more time to accomplish what can be a time-consuming mic placement and wiring strategy. The first goal is to discover a venue's aural personality. Survey it from the standpoint of how sound moves air and how it reflects off of hard surfaces and is absorbed or diffused by soft surfaces. Being cognizant of how a crowd will be situated will also affect how mics are set. As front-of-house engineers are playing back music and monitor engineers are tuning up the stage system, this is a great time to walk around, looking and listening. It is essential to walk about the stage looking at close-up instrument mic placement and listening for other potential problems. It's also important to walk around the venue looking for undesirable noise sources, such as air conditioning ducts.
Soundcheck and rehearsal is the time to be moving between the truck, stage and audience areas, making adjustments to stage and room mics as you compare what you hear acoustically to what you hear in the recording truck.
The two goals are to capture the emotional realism that the audience helps provide and to document the character of the venue being recorded. Together, these elements create an aural signature that can become an integral part of the final product and lend a unique character to each recording.
Miking techniques will vary depending on the situation. The idea is to record different perspectives from various places in the room and later combine them in a surround environment. A series of wide-spaced pairs placed at intervals from stage to back wall throughout the venue will document sound moving through the room acoustically. Some variation of zone mics covering the audience is essential if the spaced pairs might not capture them adequately. Placing a mic pair behind the backline of the stage or at the front of the stage facing the stage can often yield useful information about the sounds moving about there. This is particularly true in acoustic performances.
By documenting air movement, spatial localization of sound dramatically improves. This localization enhances the sense of “being there” and helps convey the emotions of the live audience to the listener, thus reproducing the original emotional response in the consumer. This will always make for a more entertaining and desirable final product.
High-definition audio is an ongoing endeavor, from both technical and aesthetic standpoints. But increasing one's sensitivity to acoustics and its importance in high-definition audio will maximize the ability to make the best use of increasing technical quality. In other words, using your ears will help make the best use of your gear.
Michael Davis is the owner/engineer at Digital Audio Post (Nashville).