Digital Control of Equipment
by Jerry Vigil
Five years ago, station owners and management could toss aside brochures and articles about the digital revolution and not worry much about how it affected them. You, as a Production Director, might have done the same (but, probably for other reasons). Today, however, with the rapid replacement of the word analog with digital, it is difficult to disregard the drastic changes that have taken place. Just as personal computers have become standard office equipment worldwide and even adorn our children's bedrooms nowadays, digital equipment is here to stay, and its place in radio must be examined seriously by any station hoping to keep pace with the competition.
There exists an interesting side to this digital revolution, particularly in our radio industry. In the hallways of stations not yet ready to take the digital plunge, one can sense a hushed fear of all this "high tech" gear. It is a fear that many of us elect to dismiss. This fear, most likely, is of the infamous unknown and of inevitable change. Familiarity calms us as we walk into a studio and see a 2-track reel-to-reel. Anxiety replaces that calm as we walk into a studio and see no reel-to-reels. Why? Because, we no longer can count on our knowledge of analog recording to keep us employed in the future. Our talent with a razor blade doesn't have much use in a totally digital studio. We've been taught the language of analog and shoved into a world that speaks digital. That leaves many of us unable to rely totally on what we've learned in the past unless we stay in an analog world and resist the obvious changes going on around us. If you sense this fear of the digital domain, rest easy. There is much less to it than you dread.
To begin reducing your apprehension towards the digital domain, it might reassure you to know you are probably halfway in the digital realm already. Many of the special effects processors used in production rooms are digital. Microprocessors control your digital timer. The transmitter remote control unit you've used in your control room may well use digital technology to perform its functions. If you have an analog 8-track with a remote control unit, the remote control itself is probably a digital machine. If you have a CD player, you're into digital playback. Digital technology is all around us already, and it basically does two things in our production rooms: It controls internal parameters in a machine (or other machines much like a computer controls a printer), and it converts audio from analog to digital and vice versa.
This month, we'll focus on the digital control of parameters. There is nothing truly difficult to understand about this. For our illustration, we will deal with audio processing gear, since this is the most common digital gear found in the production studio. Consider first an old analog compressor. It might have three or four knobs on the front, along with a meter or two. Each knob controls one parameter of the compressor. One knob might control release time, another the attack time. Still another knob would control gain reduction and so on. Digital technology has made it possible to adjust these parameters, not by twisting a knob (which in turn increases resistance in a circuit thus passing proper currents to achieve an effect), but by varying the digit stored in a memory location. The digit in this memory location is then read by the microprocessor which in turn makes the proper adjustments to the circuits involved to get the desired change in effect. This is all that is happening! You don't need to know technically how the adjustments are made, you only need to see that a fully cranked knob is now represented on a display by the number 99 when the range of that particular function is 0-99. Additionally, because knobs are no longer necessary to adjust a parameter, a piece of equipment is no longer physically limited in its ability to access several parameters. So, now you can control dozens of parameters that otherwise would have made the unit much too expensive to manufacture by equipping it with dozens of knobs and potentiometers for all the parameters.
Microprocessor is a key word here. A microprocessor is at the heart of every piece of digital equipment. It is at the heart of every personal computer you've seen. It is even at the heart of a pocket calculator, and here is where half the understanding of the digital domain lies. Inside that SPX-90, QuadraVerb, or any other digital effects processor is a microprocessor chip. This chip, small enough to fit snugly in the palm of your hand, is the internal PC of the unit. It's a computer just like those you see at Radio Shack, only it is obviously much smaller, and it only runs one program -- the program described in the operating manual of the processor. Your computer screen is the LCD display on the front panel. No, it's not a 13 inch color screen, but it is a screen nonetheless. The buttons on that front panel make up your computer keyboard. From this keyboard you supply input to the computer, and the results are reflected on the display and, of course, at the audio output of the unit. You don't need to know anything about digital this and digital that to use this computer; you only need to learn how to use the computer. You need to learn what buttons to push to gain access to whatever parameters you want to play with. This takes us back to the kids with the personal computer adorned bedrooms. These kids weren't born with a knack for computers, they simply read the manual! One page of instructions showed them how to boot up a game and play it. The more enthusiastic kid read more about his computer and found out how to break into NASA's computers. One major difference between analog processing gear and today's new digital equipment is in the fact that the analog gear is easier to use simply because there are less parameters to control, and those that are available are controlled by a knob or a switch (and we all know how to twist a knob or flip a switch). Using the new digital processors requires one extra step -- learning where those hidden internal knobs are and how to adjust them. Once you've found these knobs and switches (by reading the manual), the rest is a piece of cake.
With this in mind, realize that if you still have a fear of computers and don't like reading manuals, you are not going to feel comfortable with the mini-computers in today's digital studio equipment. In the same sense, once you've played with a few digital processors, the manual becomes more of a reference tool than a mandatory first step. At this point, you begin to see all the similarities between digital processors, and they begin to look more and more like pocket calculators.
Once you've accepted the fact that you're going to have to read before you can play with your new toy, you're in for some more surprises. Terminology. Most manuals for today's digital processors are going to use abbreviations you've never seen and words you're unfamiliar with. Don't fret. The terminology is also nothing to fear. One reason there are so many new words to learn is because we now have access to so many more parameters than we're used to.
Let's take reverb units for example. If you're working in a studio equipped with old gear, you might have a spring reverb unit. Well, there just isn't much you can do with a spring reverb except play with the EQ a bit (maybe) and vary the amount of reverb. There aren't many knobs on this machine. There aren't many parameters you can control. Look at most any digital reverb unit, and you're faced with choices like ROOM, PLATE, HALL, etc. as "types" of reverb to choose from. Then you have sub-parameters like DIFFUSION, HPF, LPF, etc. You'll see parameters like INI DEL and DENSITY. Folks, unless you're into the very essence of reverb itself, you don't need to know much about most of these parameters. Remember that today's digital processors are being designed for the musician and the recording studio engineer. If you're mixing the lead vocal on a ballad you hope to be number one on the charts, you might care if the reverb DENSITY is just right, but you'll be hard pressed to tell much difference in reverb density on a voice track in a promo that is cluttered with 15 other elements, processed in your production room, then processed again on the air. This is not to say that knowledge of these parameters is useless in radio production, but there is no reason to fear the fact that you might not understand what they are and how they work. However, knowing exactly what these parameters do can open doors to creating lots of unnatural special effects. Therefore, we will still define and explain the functions of these parameters in future issues. Consider also that different manufacturers will give different names to parameters that do the same thing. This is probably done to force people to read their manuals. We can't think of any other reason.
Digital control in equipment is not always internal. MIDI keyboards use computer language to control samplers, other keyboards, and external processing equipment. Just as two computers can be linked together, two or more digital devices can also be linked with each other to provide communication and control via digital information. Once again, knowing how to control one unit with the other takes no great knowledge of the "digital domain," just a little time with the owner's manual and a little patience.
This is all very basic information, but there's not a great deal the experienced analog producer needs to know to step into the digital domain. All the new digital toys are basically doing the same thing their analog counterparts do. Only the methods have changed. The aspect of the digital domain in radio production that will be most difficult to adjust to is how to use the mini-computers you'll find in each piece of digital equipment. In the past, owner's manuals wound up in a file cabinet in engineering. There wasn't much use for them except when it came time to repair the gear. These days, the manuals are staying in the production room to help the user find those internal knobs and switches. If the gear needs repair, you'll find the expression, "put it on the bench" has now been replaced with the expression, "send it to the factory."
Likewise, "digital domain" is nothing more than a modern expression that has replaced the now old phrase, "computer age." We're still dealing with the heart of the personal computer (the microprocessor), and we still have screens (LCD displays) and keyboards (buttons on the panel); and everyone who is now comfortable with a computer can recall a time when they feared the machine simply because they didn't know it. Then they read the manual.
Next month we'll look at the other function of digital technology in radio production: Digital recording. Digital recording has given the word "edit" new meaning and offers a glaring advantage over analog recording: there is no tape hiss whatsoever. If you open a mike and record your voice digitally, what you get out of that computer is exactly what went in. This is perhaps the greatest benefit of digital production in terms of quality, especially in a multi-track situation. Take a reel of blank 8-track tape, thread it up, hit play, pot up all the channels on your mixer, crank up the monitors, and listen to the hiss. Now, imagine doing the same thing with a digital 8-track and hearing absolutely nothing!