EQUALIZATION: THE CRUCIAL PROCESS
Many novices now associate mastering with dynamics control, but it wasn’t always this way. Mastering was all about EQ, with dynamics control added as a last step to accommodate the distribution medium (vinyl, cassette).
The excessive squashing of today’s mastering appears to make EQ less important, but this is only because everything is brought up so much that indeed, differences in frequency response are flattened as well.
So, the first step in mastering (after removing any DC offset) should be to tweak the EQ to perfection. My favorite tool for this is Har-Bal (Figure 1), which makes it easy to see where there are peaks/dips/holes/etc. in the frequency response. You then correct these by drawing in a new curve with a pencil-type tool.
You need to have some experience when using this; the object is not to have a flat frequency response but a balanced one, which are not necessarily the same thing. Lacking that, a quality EQ with at least six bands (and maybe more) is the way to go, as you may need to do some “microtweaks” in very narrow regions of the audio spectrum. Once the EQ is golden, do any required dynamics processing.
MASTER IN YOUR DAW
Although most people use dedicated audio editors like Adobe Audition, DSP Quattro, Peak, Sequoia, Sound Forge, Wavelab, and others, today’s DAWs often have enough capabilities to do decent mastering: They include basic DSP (gain, normalize, remove DC offset, and the like) and the ability to insert plug-ins.
Although you can use individual mastering-oriented plug-ins, for a one-stop solution, consider iZotope’s Ozone 3 (Figure 2; Windows only). This is a “mastering suite plug-in” with parametric EQ, various analysis tools, multiband compression, loudness maximization, stereo imaging processors, and the like.
Many times, you don’t need even need to leave the DAW environment: You can bounce a mix of your tracks down to a stereo track, insert Ozone 3, mute all other tracks, and get to work. Once you’re done, export the stereo mastered version with dithering, and you’re good to go. When you save and archive the project, not only will you be saving the source tracks and project file, but the mastered version as well.
LOUDER, BUT WITH DYNAMICS!
In any given mix, occasionally transients will “pile on” each other and produce a peak that limits the maximum headroom you can use. Although limiting or compression will squash these, a better (albeit more tedious) approach is to isolate each one of these transients, and use a digital audio editor’s gain function to lower the level.
This is easy to do with various programs; for example, Wavelab includes a “find peaks” function (go Analysis > Global Analysis > Peaks tab). If there are, for example, 12 peaks that exceed –3dB, you can simply reduce the gain of those peaks (select just the one or two cycles that exceed –3dB) by 3dB. Now you can bring up the entire file by 3dB, making it louder, but without disturbing any of the dynamics except those of the 12 peaks.
PLUG-IN PRESETS ARE INVALUABLE
When I do mastering, I try to get the final version sounding as good as I possibly can, but don’t sign off until the client is happy. This is where plug-in presets are invaluable, because if the client says “I love it, but how about bringing up the voice just a little more,” instead of having to explain they should have thought of that when mixing, I can call up the preset I used for mastering, and adjust the midrange EQ a bit to make the vocals more prominent. Some programs, like Wavelab and Sound Forge (Figure 3), let you save an entire chain of presets; with others, you’ll need to save a preset for each processor you use, and load them into each plug-in individually.