Audio Monitoring, Part 1: Technology Helps Meet Challenges Aboard Remote Trucks
When it comes to broadcast audio for sports, no environment is more critical or challenging than the remote-broadcast truck. A confined space crowded with patch bays and polluted by ambient noise from intercoms makes for a stressful workplace.
“The state of monitoring in trucks is atrocious,” complains Phil Adler, an A1 who mixes NFL and other sports for CBS, echoing a widely held sentiment.
It’s not a technology problem, he adds, but rather one of video-centric expertise and culture that favors video over audio, in which such details as rear-firing ports on certain types of speakers might be soffited into walls or ceilings to save space but end up creating low-frequency standing waves because their ports are blocked. “Trucks are unnatural environments for audio anyway, with their small size and ambient noise. But there’s few people actually looking out for audio in the truck design.”
The limited area that mixers must work in, often as small as 80 square ft. or less, works against the most basic aspects of two of the most important developments in broadcast audio in the past decade: multichannel sound and expanded low-frequency reproduction. The former’s surround channels are often tucked into ceilings and cannot always be positioned to form the ideal equilateral triangle around the mix position called for by surround-sound best practices, while the crucial center channel has to compete with placement of video monitors. Low frequencies, meanwhile, usually have nowhere near the room needed to fully unroll, making accurate monitoring difficult.
The challenges that mixers face as they look for accuracy under these circumstances are nothing new. With the exception of mobile facilities purpose-built for entertainment applications, notably music-awards-show broadcasts, the audio component of most broadcast trucks tends to be subordinate to video requirements.
However, the reality is that trucks need to be as lean as possible when it comes to weight and outside dimensions, and, as an element of broadcasting, sound simply has more space requirements on a per-person basis than, for instance, a video-production control room. The latter might hold as many as 10 people monitoring a wide range of video sources on displays that range from 50 in. to as small as 7 in. and have only gotten thinner and smaller in recent years even as their resolution has increased and weight and costs have decreased.
Audio, on the other hand, graduated from one speaker to two to three (stereo and LFE) and finally to the six speakers of 5.1 surround over the past decade, adding weight and cost and requiring additional space to create the most basic listenable surround-monitoring configuration for the use of essentially a single person: the A1 mixing the show. LCDs are designed to allow effective viewing from even oblique angles, allowing wide latitude in placement; speaker performance, on the other hand, is highly specific and contingent on any number of interactions with reflective or diffusive objects, such as mix consoles and brackets.
“You have to be very careful how you mount speakers, to avoid masking frequencies and creating reflections,” explains Chris Fischera, VP of Group One Ltd./Blue Sky International.
The physics behind each domain’s various needs are clear to those who use them, but, from an accountant’s perspective, it might be easy to understand why audio seems to get short shrift in truck budgets. Nonetheless, audio mixers have long seen a bias toward video in broadcast culture. “They’ll think nothing of authorizing a $120,000 camera lens but will say a $360 microphone will break the bank,” gripes Fred Aldous, audio consultant and senior mixer for Fox Sports.
However, technology also offers some solutions. Speakers have become smaller and lighter in recent years, thanks to the use of new metals and more-efficient drivers. But the biggest advance is the application of auto-calibration DSP, which uses software to generate sweep tones and other specific frequencies that the software can use to electronically map the room’s acoustical topography, looking for such hazards as reflections from parallel surfaces and frequency-blurring nulls and correcting for these anomalies using equalization and delay algorithms.
Genelec, which has a substantial market share in mobile broadcasting, has adapted its auto-calibration DSP capability to its SE (Small Environment) system, scaled for smaller speakers in tight environments. Will Eggleston, director of marketing for Genelec, acknowledges that the cost for a 5.1 surround system with the SE DSP is relatively high for broadcast-audio monitoring, around $10,000. But, he adds, it’s also insignificant compared with the overall cost of a truck, which runs several million dollars, and adds considerably to a truck’s capabilities, allowing it to be used for a wider range of applications.
Eggleston believes that auto-calibration solutions are inevitable. “The technology is out there, and it’s just a matter of time [and] electro-acoustic expertise, along with proper coding and testing,” for it to be more widely implemented.
JBL Room Mode Correction (RMC) system compensates specifically for low-frequency irregularities with a system that measures the room’s frequency response and applies corrective filters and is available for all of JBL’s LSR series speakers. Blue Sky, whose speakers are found in many trucks commissioned by ESPN, plans to roll out its own auto-calibration solution by the end of the year.
Technology solutions can go a long way toward correcting some of the most egregious monitoring problems in trucks, but there’s a limit to how much help they can offer. That’s where truck design comes in. A look at how mixers and truck builders are working to improve the audio-monitoring environment will follow on Thursday.