Broadcast and production audio consolesBy Dave Hansen
This year, the U.S. government heightened pressure on the broadcast industry to get DTV online or pay the consequences by instituting a “graduated system of penalties” for those stations that did not meet the deadlines. Despite this pressure, only 413 of the 1240 U.S. television stations are currently transmitting digital signals, according to a recent article in USA Today (July 19, 2002).
At KTVT in Fort Worth, TX, the Euphonix System 5-B audio console features a 32-fader surface controlling 88 processing channels, 24 mix busses, 24 group busses and 16 aux busses. The station interfaces this processing with 24 microphone preamplifiers, and 48 AES digital inputs and outputs. Photos of System 5-B consoles courtesy of Euphonix.
There are thousands of other facilities in the United States and worldwide that provide content (such as entertainment and sports programming, live or live-to-tape) that will benefit from working in a digital environment, but they are not yet doing so.
Facilities must undergo three stages to transition from analog to digital broadcast. First, they must install digital transmitters and antennas. Second, they must upgrade the master control infrastructure to accommodate digital signals. Finally, they must convert the production environment, which creates the facility’s content, to all-digital audio and video equipment to realize the full benefit of digital broadcast technology. This third stage includes updating the audio console, which is the focus of this article.
Audio console manufacturers have been working furiously to provide products for digital audio applications in broadcast, and have been making viable products available for over five years. Initially, digital consoles for broadcast production were fiercely expensive — upwards of $600,000. Such costly products were installed mostly by large networks at facilities in major cities. But the diversity and accessibility of digital consoles has improved markedly. Today, digital consoles are marketed for all audio applications: music, film, short-form post, long-form post, live monitors, PA, broadcast production and broadcast news. The capabilities and prices of consoles range from relatively inexpensive off-the-shelf line mixers costing less than $50,000 to custom-built products costing half a million dollars or more. With all the new choices, the engineer’s task has increased in its complexity. To choose a new console, he must first compare a huge selection of consoles, then select the one that will meet his needs, and then justify the purchase. He must then figure out how to incorporate it into the existing infrastructure, or conversely, create an infrastructure that will accommodate the product. But how does one understand the increasingly complicated terrain of audio consoles?
In this remote truck operated by Australian Broadcast Corp. (ABC), Sydney, Australia, the audio console features 32 fader surfaces controlling 40 processing channels, 24 mix busses, 24 group busses and 16 aux busses. ABC interfaces this processing with 48 microphone preamplifiers, and 80 AES digital inputs and outputs.
Broadcast and production audio consoles are different, reflecting the specific requirements of on-air (broadcast) or off-air (production) applications. A broadcast is immediately distributed to viewers, whereas a live-to-tape production is stored, edited (albeit sometimes only slightly) then sent to a broadcast distribution medium.
A broadcast console needs many more auxiliary busses to manage the various submixes and output destinations needed to rapidly transition between field reporters, studio-based anchors and taped segments. Mix-minus is an absolute necessity for creating custom mixes for reporters standing by to come on the air. Stereo channels are required for manipulation of taped segments. Snapshot recall of parameters is important to enable broadcasters to recall the show’s baseline settings at the beginning of the next program.
In contrast, production consoles need dynamic automation to allow for the variety of offline manipulations (such as “sweetening”) that occur in post production, and for mixing in other elements (such as multitrack music) after the show is recorded. For example, production consoles used in a variety show generally require a large number of faders to accommodate live musical acts and other featured showpieces. When budgets allow, production planners should consider purchasing a separate console to handle the musical elements, to better showcase the show’s musical assets and, more pragmatically, to reduce the workload of the operator on the primary console.
When choosing a console, carefully consider whether it will be required for broadcast only, or for both broadcast and production. In the latter case, it is essential to select a mixing system that is modular and expandable to accommodate change.Digital’s time has come
Analog facilities are becoming increasingly rare, and it is safe to say that digital is here to stay. Digital wins on pricing alone, based not only on the cost of the console itself but the extra equipment needed to integrate an analog console into an increasingly digital world.
But cost aside, digital technology offers the advantage of making audio production consistent and reliable. Many digital consoles now offer fully recallable parameters, ranging from channel and fader assignment to equalizing and filtering, as well as complete patching setups, and even automation for live-to-tape audio sweetening. This not only enhances the versatility of an audio console, it opens up profitable business opportunities for a facility. For example, a facility with news full-time during the week can lease the room on the weekends for other programs. Come Monday, the facility can completely recall the news “setup” and the daily show can go on.
This console at KOMO, Seattle, features a 48-fader surface controlling 88 processing channels, 24 mix busses, 24 group busses and 16 aux busses. The station interfaces this processing with 24 microphone preamplifiers, and 48 AES digital inputs and outputs.
Some consoles use the latest touch-screen technology to bring features to the surface and make them readily available to operators. And software-based architectures allow console owners to add upgrades at a very small cost compared to buying new hardware.
Reliability is a key factor for broadcasters: There’s only one chance to get it right on-air. Built-in redundancy for power supplies and other key components to keep audio live are standard offerings on many digital consoles.
Most digital consoles are built on the assumption that the signals, once digitized after the microphone and line converters, will stay digital throughout the audio chain. This eases integration into digital video systems. And, since no extra third-party boxes are needed, it reduces costs. Some consoles use multichannel audio digital interface (MADI), which is run on standard coax with BNC connectors. This single, compact cable carries 56 channels of audio and is very cost effective. (For a technical analysis of MADI, see the Audio Engineering Society publication: http://ftp.aessc.org/pub/aes-10id-1995.pdf.)Broadcast consoles
Typical broadcast (on-air) applications include news, sports and special live events ranging from holiday coverage to political conference and debates.
Consoles that can be easily expanded with more faders and channels are more expensive at first, but they save money in the long run. Nonetheless, for smaller-scaled operations, less expensive, preconfigured consoles can get most non-network broadcasters up and running and keep them there for a decade to come.
A network news organization would probably need a console with 40 to 56 faders, 48 channels of microphone preamps, and 72 to 96 channels of analog and digital I/O. Roughly speaking, expect to pay from $350,000 to $500,000 for this capability. The typical network-owned-and-operated station, or an affiliate-news-level facility in the “above 50” category would probably require a 32-fader console with 24 channels of microphone preamps and 24 to 48 channels of analog and digital I/O. Expect to pay from $150,000 to $275,000. At the affiliate news “market 50-100” level, expect to pay about $75,000 to $150,000 for a suitable console, with capabilities decreasing as cost goes down.
At Tribune Entertainment in Los Angeles, the console features a 32-fader surface controlling 70 processing channels, 12 mix busses, 24 group busses and 16 aux busses. Tribune interfaces this processing with 48 microphone preamplifiers, 24 analog inputs and outputs, and 72 AES digital inputs and outputs.
Basic capabilities for any of the above-priced consoles should include 96 channels with equalizers and limiting, inserts and configurable mix busses with the ability to create at least eight stereo subgroups and two stereo programs, one mono program and one 5.1 surround program simultaneously. In addition, the console should have 24 clean feed outputs for floor feeds and custom mix-minus setups, 12 aux and N-1 mix-minus for remotes.Production consoles
For variety-show and talk-show types of live-to-tape productions, a console needs automation and more faders and channels than for on-air broadcast consoles. A large production console should include 150 to 300 channels with EQ and limiting, inserts, and configurable mix busses with the ability to create at least eight stereo subgroups and two stereo programs, one mono program and one 5.1 surround program simultaneously. A 32-to-48-fader console for network-level production will likely fall into the $275,000 to $500,000 range.
For broadcast and production situations, a production console can be configured with the necessary broadcast amenities like mix-minus and extra auxiliary outs.Selecting an audio console
The first step in determining your facility’s console needs is to assess the facility’s daily audio requirements. Depending on whether you are broadcasting news vs. sports, you will need to consider a distinct set of console functions. For instance, does the console need to function for both live on-air shows and live-to-tape shows?
Will there be audio sweetening in the live-to-tape productions? Compile a list of the range of productions the facility will handle, and then closely examine the functions that each requires. If you’re unsure of these requirements, find someone who has built a similar production studio and seek his or her advice.
The old adage “the devil is in the details” certainly holds true here. For example, something as simple as sharing microphone preamps between two stages can seem like an obvious capability, but some consoles, even some very expensive ones (over $500,000), lack microphone preamps that can be easily networked and controlled from the console directly. For such consoles, you must purchase a separate piece of equipment or a complete new set of compatible microphone preamps. Therefore, it is well worth investigating which manufacturers offer networked microphone preamps already integrated into their system. See the sidebar for a checklist of other features to consider when shopping for consoles. Figure 1 shows the interconnect diagram of a digital console with integrated control surface, processor and I/O.Support features and products
If the console you’re considering doesn’t include an integrated router, look elsewhere. In the digital world, this is often the most used and sometimes the most expensive piece of “extra” equipment that you need to purchase. Some manufacturers have taken this into account and have recallable routing for all I/O. And though the console itself may seem a bit more costly than another, having to purchase a separate, fully functional digital routing system (which won’t feel integrated) may cost even more.
Figure 1. A typical digital console interconnection diagram showing the control surface (faders, etc), connected to the DSP processing and I/O units.
Confidence metering is the most important feedback for broadcast engineers, not only to know whether a signal is on a certain channel in the console, but more importantly, to be certain that that same signal is getting to the broadcast distribution chain. Audio mixing for broadcast is all about managing signals and giving individuals the signals they must hear to do their jobs. Some consoles include certain built-in features for confidence metering, which offer convenience. However, the best confidence meters are built-in by engineers along the distribution chain. Therefore, internal confidence meters should not be a priority when selecting a console.Maintenance issues
Many pieces of audio equipment come with basic warranties, but six months and a 1-800 phone tree isn’t enough for a complete broadcast audio console. Make sure you understand what kind of warranty a console comes with and what kind of extended or renewable options are available. Some companies will offer services like consultation on how to install the units, special pricing on extra spare parts, software upgrades, and personal visits to make sure the facility’s needs are met and the production is on-air around the clock.
Facilities should a have staff that is familiar with basic concepts and components of digital systems and computer technology. A proficient IT team, which is readily available at most facilities, is essential for employing today’s digital computer-based marvels. Onboard diagnostic software routines can help staff maintain the system. The facility technicians can learn the diagnostic routines and help locate and pinpoint problems if they arise.Planning the transition
The most difficult aspect of upgrading from an analog console to a digital one is to keep the show running while the new equipment comes online. Conscientious console companies will help plan transitions, but even so, facilities should have a concrete plan of action before embarking on an upgrade. Manufacturers should provide complete technical documentation online for facility staff to reference during planning, construction and installation.Getting help
As with any new technology, there will be knowledge gaps. Most facilities are part of a larger corporation whose personnel have experience in digital technology. If so, you can draw on this resource. If such expertise is not available within your company, find someone with experience and, if necessary, buy a few hours of expertise during the planning and installation process. In addition, the larger console manufacturers have product specialists with experience in successfully implementing their consoles into a wide variety of facilities. Technology consultants are also available. With the right help, transitions can be smooth.
Extensive research into digital audio consoles before a purchase is of paramount importance. Avail yourself of the extensive technical documents, client information, news and other resources available on the manufacturers’ Web sites, or just give them a call. Browse the Web and collect information. Join or browse some discussion groups (“rec.audio.pro” link from Google/groups at www.google.com/ or groups.yahoo.com/group/Broadcast), meet some new people and find out what’s going on. One thing is sure: It’s a digital world and digital consoles have arrived to serve it.Dave Hansen is vice president of product marketing at Euphonix.
Selecting a digital console
Whether upgrading a current analog console to digital, or putting in a complete new studio with a digital audio console, there are three primary considerations: control surface, signal processing, and inputs and outputs (I/O). A few of the most important considerations are outlined below.
Control surface must be ergonomic. Stated rather obviously, features that are most frequently used by operators should be at their fingertips. A programmable control surface is a big plus, as it can be customized to the operator and application. For broadcast, consider talk-back to busses, backstop pre-fade listen (PFL), after-fader listen (AFL) solo, general-purpose inputs (GPI) control, and redundant power supplies. For production, consider dynamic automation and machine control.
With regard to signal processing, there should be enough digital processing capability to handle the required application, with room for expansion. Look for the ability to program the digital processing unit to suit your application, and note that this capability is not available on all consoles. Programmable items should include signal routing, equalization (EQ), filtering, bussing and monitoring. For broadcast applications, look for mix-minus, redundant PSU and RAID array for system computer. In production, multitrack busses, full dynamics processing are important. Make sure the system is 5.1 surround capable.
I/O should be modular and expandable and shouldn’t require purchase of additional equipment for mixing and matching digital and analog I/O hardware. For broadcast, consider redundant PSU, 75V AES interface and integrated routing. Some considerations for production include support of all digital formats such as SDIF, TDIF, AES/EBU, etc.