Passing the Audition

 
Passing the Audition

Tips and tricks for mastering and recording in Adobe Audition

By Jon Rose

Electronic Musician, September 2003

When Adobe Systems recently purchased Syntrillium Software's technology assets, a new era began to unfold for Cool Edit Pro. By the time you read this, the name likely will have already changed: Syntrillium's Cool Edit Pro has become Adobe Audition.

Changes in Adobe's release of the software under its new moniker are primarily cosmetic. The direction that Adobe plans to go with Audition is not yet clear; for now, though, the software remains a standalone audio application, and its basic functioning has not changed. Because it would be impossible to explore all of Audition's features in a single article, this Master Class will focus on using the program for recording and mixing music. Audition is relatively simple to use and intuitive enough for novice users, but there's far more to it than immediately meets the eye. (Take a look at the sidebar “Audition Overview” if you are not already familiar with the program.)

Seasoned recordists can readily adapt and apply their knowledge to Audition. For the less experienced, a little logical thinking on your part can determine a workable session layout for the Multitrack view (the Edit view is designed for destructive stereo editing). Shortcut keys for the various functions are real time-savers, so use them! Press Alt + K to change or add keyboard shortcuts. Fully displaying all toolbars can save lots of time (right-click in the Toolbar area for options). The button icons for the toolbars are fairly descriptive, and hovering the mouse over them can remind you of designated shortcuts.

FIG. 1: Using the Merge function, which converts sets of cues into ranges, and the Batch function, which allows file saving, you can create a series of individual files from a list of cues in the Cue List.

Even if you're recording a stereo pair of microphones (or a mixer feed), you should still use the Multitrack view for live recording. The Edit view limits your recording time to however long it takes your chosen resolution to reach 4 GB, and that could spell disaster in a live situation. In the Multitrack view, audio is automatically divided among multiple temporary files, so hard-disk space is the only limiter. After you stop recording, drop in cue markers (F8) between songs or at other logical points. (If you “baby-sit” the computer during the show, drop in your cues on the fly.) Then drop a cue at the beginning and at the end, and press Alt + 8 to open the Cue List. Highlight all of the cues and choose the Merge function, which converts them to ranges (see Fig. 1). Using the Batch function (its dialog box is self-explanatory), save your selections as separate files, and you have a viable work-around for size limitations on audio files.

Set Audition's temporary directories for your fastest, largest drives (press F4 and then find the System tab). If you have only one drive available for recording, don't even define a secondary temp directory. Many people misinterpret the term reserve value — that is the disk space the program won't use, so don't set it to some huge value and expect to record for long periods!

Assuming you have a multi-I/O audio card in your computer (or two or three, as I do), you can feed your computer lots of channels. Be certain, though, your system is optimized in advance. Test your disk-bus throughput. Will it simultaneously support as many channels as you want it to? Don't wait until the gig to find out!

Lay out sessions that make sense to you. Define conventions and stick to them, particularly if you're going live for the first time. You can easily reorder your tracks by right-clicking and dragging the Track Properties areas up or down in the Multitrack view, but that can waste session time and cause missed takes. Now, some might safely ignore this advice and be just fine without it. But since recording and mixing is how many of us feed ourselves…

Time is money. Clients get impatient and testy, even when they aren't paying for setup and downtime, and shows are a one-chance proposition. Create several different session templates for different types and sizes of projects and keep them handy. Lay out a generalized session and save it as the default session in the File menu. Choose the sampling rate and bit depth that you'll use to record, though — this information is saved with Audition's sessions. Whatever sampling rate you choose, use the highest bit depth that your audio card allows and mix using 32-bit, floating-point files for little or no degradation to the audio.

Zipping up and down through the mix with a modern, scroll-wheel-equipped pointing device is effortless; but wasting time trying to find a particular track isn't. Practice getting around in your new session layouts, and do that before the gig, too.

FIG. 2: Effects are added to tracks by using the Effects Rack in the Multitrack view. QuickVerb, in the Delay category (shown here), uses less CPU power than other reverbs and still sounds decent.

External cue mixing almost always necessitates a multiple I/O audio card, a mixer, and outboard gear, but if you don't have multiple I/O, you can work out some parts of your cue mixes directly in Audition. For a decent-sounding reverb that won't overtax your CPU, open an Effects Rack, expand the Delay Effects list, highlight and add the QuickVerb to the Rack, and press Apply (see Fig. 2). Adjust the reverb's parameters, lock the effect (to take the load off your CPU), and you're ready to roll.

Too many people discount the usability of the track EQ. Highlight a track and press Alt + 5. These 3-band parametric track equalizers are fast and easy to use and are valuable in final mixing, too.

To use a dynamically unruly track in a cue mix, insert a compressor/limiter from the Dynamics Processor into that channel's Effects Rack and adjust as necessary. Some players don't even realize it, but inconsistent drum hits are very distracting and disorienting, even if they're precisely in time.

You don't have to make the tracks perfect while you're overdubbing; just get them under control quickly (with reasonable dynamics) and into a usable space for your clients. Using the Effects Rack, Mixer window, and the Track Properties areas, you can quickly massage a cue mix into shape. Pan, EQ, and time-delay effects are all nondestructive effects that you can remove, tweak, or change later during final mixing. Use whatever you need to move the session along so that creativity isn't compromised, and save the fine-tuning for later. Also, think about whether that unruly track will be usable later, and try to be objective as you work.

In native applications, everything runs on a single microprocessor, so budgeting your system resources is paramount. If you're adding lots of effects to your cue mixes to make your talent happy (hey, it's their money, right?), be sure that they're locked. Locking effects averts potential recording dropouts by temporarily rendering effects to Audition's temporary files, thus taking a load off your CPU.

FIG. 3: Right-clicking on the green Background Mix bar brings up its context-sensitive menu.

Your system will perform differently if you change your Background Mix priority settings (see Fig. 3). Those settings determine the amount of time Audition devotes to premixing tracks for playback and how far ahead it works. Right-click on the Background Mix bar to quickly make changes. Depending upon the complexity of your project, you might need Audition to mix farther ahead or with higher (or lower) priority.

The relationships between a project's complexities, track effects, and mix priorities, and your system's speed and resources are critical. If that sounds nightmarish, don't let it scare you off. There's no single setup that works in every situation, and this fine-tuning process is akin to setting your audio card's record and playback buffers. To get the right settings, you'll have to experiment, especially if you are pushing things hard. From the View menu, enable the Load Meter, which provides a quick visual reference of CPU usage.

Turn off virus scanners, TSRs (terminate-and-stay-resident programs), unneeded system services, Microsoft Messenger Service, and any other unnecessary background applications. Install current drivers for all your devices, especially your video card, or you'll suffer a serious performance hit. (Audio and video applications are resource hungry.) Optimize your system!

Despite the hype surrounding digital audio, not every problem can be repaired, removed, or overcome. Some things, such as overload distortion, can never be fixed. There are tools that might help with the little things, but those “little” things can constitute some of the most annoying and obstinate problems you'll ever encounter and are sometimes the most difficult to isolate.

Let's say, for example, that your tracking is complete, the talent has left the building, and you spot a simple (albeit common) problem: a nasty click. Audition has some highly adjustable restoration tools that can be used creatively to a mixer's advantage.

FIG. 4: Clicks and pops can often be eliminated using the Fill Single Click option in the Click/Pop Eliminator effect. Fig. 4a (top left) shows the area of the click; Fig. 4b (bottom left) is a zommed-in close-up. Fig. 4c (top right) shows the click in the Spectral view, making it very obvious (note the bright vertical area); and Fig. 4d (bottom right) shows the result of using the Click/Pop Eliminator.

In Edit view, isolate the area where you hear the click as best you can. Zoom in and refine the selected region until you can still hear the click while looping the zoomed selection. Zoom in vertically too, as needed — you're looking for a very fast rise time (or a sharp fall) in the waveform. Fig. 4a shows a tiny piece of a waveform, but the problem is difficult to see. A closer look in Fig. 4b reveals the problem: the click is only two samples long. Toggle the display to Spectral view (Fig. 4c), and the click is painfully obvious (many people use this view for search-and-destroy work). To solve the problem, I selected a range that extended beyond the click and enabled the Fill Single Click feature in the Click/Pop Eliminator. Fig. 4d shows the smoothed result.

Here's another related problem. In a quiet room, hold a smooth, flat object (or your hand) a few inches in front of your mouth. Open your mouth and close up the back of your throat with your tongue. Move your tongue all around, listening carefully. The mouth and glottal noises you hear are common with inexperienced singers and speakers and can happen with professional talent when they're a bit dry or tired. You can clean up these high-frequency glitches using the same method I used for the click, but now for the unorthodox tidbit: because you can select an area up to 5,000 samples wide when using the Fill Single Click option, sometimes you can quickly surround and reduce the lower-frequency glottal noises, too! With a quiet passage in which the voice is prominent or there is only speech (and gating might therefore be too obvious), using this trick along with some clever editing and EQ might be your best bet.

Noise reduction is too involved to address thoroughly here; in general, however, experiment with the Spectral Decay setting and don't try to cut the noise too deeply (keep in mind that getting good results always depends on the material you're working with). Carefully select your noise profiles. A quiet concert recording that has air-handler noise in the background can certainly be improved, but be careful that your reverb tails don't disappear into digital artifacts! You might even try reversing a waveform and applying the noise reduction that way.

Some folks have never worked with a quality hardware equalizer, and many more don't yet have a trained ear. Audition's Parametric Equalizer is a powerful tool for finding frequency-related problems, and by following these steps, you can make it work for you (watch carefully!). You'll need to grab the file honkguitar.mp3 to try this one at home.

FIG. 5: Creating a sweepable peak with the Parametric Equalizer is a useful way to identify problem frequencies.

As you'll notice, this file is a short acoustic-guitar track with a slightly honky sound. Load the file into the Edit view, highlight the track, and open the Parametric Equalizer. (We won't be using any of the sliders directly adjacent to the graph.) Select the Reset To Zero (Flat) preset in the Presets list. In the middle of the screen on the left, click on box 3 to enable that filter — a new dot appears on the graph. We're about to raise the volume of a narrow band of frequencies, so before doing anything else, type “-15” (minus 15) into the Master Gain value field (bottom center) or reduce your monitor level considerably. This EQ is an Infinite Impulse Response (IIR) filter, which can ring or feed back. Now, to the right of the graph, drag slider 3 upward roughly +15 dB and note the graph. Next, enter the value “40” in the third filter's Q parameter field (marked Width). Observe the graph — our filter got narrower (see Fig. 5). Click on the Constant Width radio button and the Q value should change to a frequency range of about 20 Hz.

Now click Preview to loop your selection. Here's the fun part: in the Center Frequency area, sweep the third slider slowly back and forth with the mouse. The filter peak we've created will exacerbate the honky part of the guitar. Congratulations, you've just identified your problem frequencies. Slowly reduce the level slider, listening carefully as you pass zero. A slight cut should help, but you might need to increase the filter's width.

This procedure allows easy location and mitigation of many such problems. When you're comfortable using this technique, you can safely grab points on the graph with the mouse and move them around. After some practice, try sweeping your filter with a cut instead of a boost to obtain this result directly. It's not as easy to hear this way, but it's a great training tool for your listening skills.

Audition is loaded with effects and processors, and a thorough exploration of the subject would require another entire article — the list of parameters is just too vast. Experimentation is often the best approach, but I'll give a few suggestions to get you going.

FIG. 6: Laying out the segments of a project sequentially on successive tracks can be useful when mastering a project. Among other benefits, all tracks and processing are easily accessible.

Mastering in Audition can be approached in many ways, depending on the material. Some users find it easier to work primarily in the Edit view; others compile and master their mixes by arranging the segments of a recording sequentially in the Multitrack view (see Fig. 6). The advantages of that tack include being able to use effects and processors, such as the stacked band-limited compressors I mentioned previously, as well as providing quick and easy access to every element of the project. And the Edit view is still only a button (F12) away if you need it.

Of course, well-mixed audio segments, whether music, voice, or what have you, really shouldn't need much in the way of mastering. But when you're satisfied with your track-to-track balance and any desired processing, select all waveblocks and mix down the entire project, which will drop you into Edit view. Hopefully you've been working at 32-bit, so you'll need to convert to 16-bit (and maybe downsample) for CD (press F11 to access the Convert Sample Type dialog). Add your CD track cues, merge everything into ranges in the Cue List, batch everything out to separate files, and you'll be ready to fire up your favorite CD-writing software.

I hope you've enjoyed this brief survey of recording and mastering in Audition. Check out the sidebar “Ten Quick Tips” for some additional useful pointers. And keep your eyes out for even more developments in the Audition world. No doubt the folks at Adobe have some exciting tricks up their sleeves!