digital audio console update - TvTechnology

digital audio console update

Standards for the broadcast industry are in a state of flux that forces the manufacturing industry - who in some cases must apply years of research before
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Standards for the broadcast industry are in a state of flux that forces the manufacturing industry - who in some cases must apply years of research before introducing a product to the market - to make educated guesses as to the future needs of its customer base. Early estimates as to the penetration of HDTV by the year 2000 were much higher than the actual number of homes receiving these signals at this time. However, few doubt the attraction of detailed, large screen images and uncompressed 24-bit audio sampled at high rates will one day be the broadcast norm.

Audio for picture console technology is changing as well. The move to digital boards, well established in the recording business, has taken a bit longer to revolutionize the broadcast industry, in part because of a fear that single-point failure could cripple an on-air presentation. But this migration continues, and a number of manufacturers are releasing all new digital broadcast consoles this year. In this article, we review the current state of affairs regarding consoles built for broadcast.

What distinguishes an on-air console from a post or recording board? Perhaps the most significant point of departure lies in the fact that on-air consoles are ideally designed to optimize their integration into an open communications system, one that requires the mixer to receive information from outside sources and respond to it quickly. Routing to a variety of output targets, due to multiple format targets, is also crucial. Absent the live element and the need to participate with team members outside the studio, mixers working on records and in post applications require less extensive communications systems - perhaps no more than a simple talkback package. On the other hand, recording engineers in particular require processing capabilities, equalization especially, that are much finer than those used in live television.

The pressure of live broadcast applications has had a direct impact on the divergence in the way consoles built for this need and those used in other areas of the audio industry has proceeded. The relative quality of I/O conversion and equalization may be debated. (A/D and D/A converters across the spectrum have gotten better and better over the last several years, but the gap separating the "best" from the rest is arguable.) The fact is James Taylor recorded and mixed a very good sounding record with engineer Frank Filipetti on a Yamaha O2R console that costs less than $10,000. Major releases from other artists have been taken from concept to conclusion on inexpensive digital boards, or at the very least have incorporated them into the tracking process as well. However, the way of achieving these economies of scale is to layer as many functions as possible beneath each piece of on-board hardware and incorporate a small LED screen as the single visual reference. These tradeoffs are ones that cannot be made in on-air circumstances.

The assignable aspect of inexpensive digital consoles renders them unfit for live broadcast applications and re-establishes the comfort factor of the traditional analog model (one fader per input strip and dedicated hardware). However, the allure of automation, perhaps more than any other single benefit that digital boards bring to the table, has cast its spell over mixers in every area of the audio business. The major manufacturers and some smaller companies are vying for market share by assessing how much real estate networks are willing to invest in hardware and balancing the expense involved in fulfilling this requirement with a digital package that manages the console and perhaps shrinks the cost by reducing the amount of hardware required.

Given the rising level of sophistication among users of digital consoles, several manufacturers are now releasing product that allows the operator to tailor a board's assets to suit the individual's need. Engineers tracking a music session need at least 24 tape inputs but require less extensive routing to external sources than would be needed for an on-air broadcast, and would therefore call up an appropriate model prior to their session. Broadcast mixers might require no tape inputs whatsoever, but would need more extensive routing, and would therefore begin their workday with a different configuration.

The fact that audio is often delivered in parallel streams, with mixers having to account for viewers listening to the audio portion of a broadcast in stereo and mono as well as 5.1, puts a monitoring burden onto a system that would not exist if audio was being downloaded into the home in a uniform fashion. Without question, the engineer working on broadcast audio has to be able to mix in surround while at the same time ensuring that viewers listening all the way down the line to a mono environment will be receiving the proper dynamic range. Are the advantages that features like these bring worth the expense? These are the kinds of questions broadcasters must answer. Remember, you can patch in a DAT player, a couple of CDs and a mic array to a console that costs no more than Johnny's first semester college bill, but can you live without the features you're giving up?

Flexibility is unquestionably the key factor. Along with the requirements imposed by the move to DTV, HDTV and 5.1, the adoption of the new Dolby E format, used to manage metadata on audio that passes through stages within a facility, has increased the routing demands placed on broadcast boards. As more and more processing takes place within a mixing environment, broadcasters' fears of single-point failure are rising. Computer redundancy, essential to allaying these concerns, is being built into most of today's high-end consoles. Different applications within the broadcast industry require different levels of redundancy. A facility that handles major sporting events and other prime-time live programming might be willing to pay more for extra back-up capabilities than one that takes network feeds until 1 a.m. If you're not sure how great your redundancy demands will be, it may be possible to get the manufacturer to agree to loan you the equipment until the console has passed through an initial trial period.

Are some consumers over-emphasizing redundancy? Manufacturers of consoles that use the Unix platform rather than the ubiquitous Windows or NT systems point out that the Unix platform, which is used to run air control systems, hospitals and banks, is more robust and less prone to failure than the others. Redundant power supplies may protect the console itself, but if the system relies on a less-than-stellar software platform the security may prove ephemeral.

Perhaps the chief advantage of analog consoles centers on the fact that individual console strips can be swapped in a manner of minutes. What variables exist in the digital realm, where strips are virtual? Different digital consoles plan for disaster differently, or not at all in the case of the smaller boards intended for the home recordist.

Since all digital consoles require some kind of sacrifice in the one button per function, one strip per input model that has been handed down from their analog predecessors, the way the requisite trade-off is handled is a hotly contested battle ground. Will a small set of mixers be working a broadcast console, or will a variety of freelancers be handling sessions? A team of mixers who will be given a week of training by representatives from a manufacturer upon purchase may be willing to sacrifice a bit of initial ease of access in order to take advantage of other features they value, but no facility can afford to have an independent engineer learning a challenging board on the job.

A firm understanding of a facility's current analog and digital routing, coupled with a confident projection of where this large configuration will project out over the next 10 years, is critical to the broadcaster shopping for a console in today's market. If a facility is holding on to a 2-inch 24-track tape recorder but plans on replacing it with digital equipment, the required number of analog tape inputs diminishes. A fundamental theme continues to re-establish itself: Spend time making projections on the way the rest of your facility will look a decade from the point of your purchase. Then gaze into your crystal ball and make an educated guess as to the state of digital broadcasting at the end of that period. The console you buy needs to be able to handle all of your current routing needs and those you anticipate. Many facilities faced with the need to purchase consoles for two or more rooms will try and save money by buying a reduced feature set for the board that will sit in what is today an offline space. Be careful. You could be penny wise, but pound foolish if in a few years your studio goes through an upgrade and you desperately need the functionality you sacrificed for short-term savings.

Another factor to consider when purchasing a broadcast board is the age of the technology you're buying into. If you value the track record of a well-established console manufacturer, then that factor will surely influence your buying decision. Competitors touting the advantages of newer digital techniques might try to caution you against buying into technology that's teetering on the edge of old age.

Consider one of the hot topics in the recording industry for a moment. The CD standard of 16 bit/44.1kHz has clearly been surpassed. Without a doubt audio recorded at the 24 bit rate captures the range of perceptible volume steps more realistically, and with greater detail, than its predecessor. Similarly, sampling rates of 88.2-, 96- or even 192kHz yield require less rounding off of material, especially the upper frequencies, than the norm of today. But how quickly will audio DVD or its competitors that take advantage of these advances catch on with the public? Many listeners find the experience of listening to highly compressed MP3 files straight from their computer fully satisfying. Anticipating consumer demand and building rooms that can handle audio as it will need to be delivered in the future may make or break a number of recording facilities.

Things aren't so different in the broadcast area. Literature touting the fact that its console ships ready to roll at 96kHz may be enticing, but will a broadcast path that contains this sampling rate ever become a reality? If a studio saves money by purchasing a console that tops out at the current industry specs will the decision turn out to be wise in the long run?

In the final analysis, it is certain that the days when poorly recorded audio with audible air conditioner noise, for example, will be masked by the poor quality of home playback systems are fading. The digital console is here to stay, based on the allure of automation and the strength of software. Nonetheless, savvy studios and broadcast facilities need to be educated consumers when it comes down to choosing from the current crop of audio for broadcast consoles.