The last time I discussed vocal microphones for CPM, we talked a lot about what makes a mic a “vocal” mic, and about how you might go about choosing the right one. We'll revisit that today, but we'll also talk about good mic technique, as well as effectively approaching your processing (such as EQ and compression) so you can get the most out of what you have. Let's jump in.
WHAT MAKES IT A VOCAL MIC?
First, let's review what makes a mic a vocal mic, specifically. You know those really annoying pops that can sound like explosions when someone says a “p” or “b” word? Those are plosives, and when you say a “p” or a “b,” a burst of air comes out of your mouth. Microphones don't handle that well, so the result is an unpleasant boom. The single biggest physical difference between vocal mics and, well, non-vocal mics (not a real term) is that vocal mics have a larger grill and internal windscreen designed to help thwart plosives.
Some vocal mics have intentional EQ internally to bring out upper-midrange frequencies (for the theoretical intent of better clarity or getting the vocal to “cut” more), although I don't usually prefer that. You can determine that by looking at the frequency response graph in the specification (or spec) sheet, which is often part of the marketing literature.
In the end, you can certainly use a vocal mic on an instrument (or vice versa), as long as it behaves well for you.
CHOICES
Choosing the right mic involves multiple choices: dynamic vs. condenser; cardioid vs. hyper-cardioid vs. something else; wired vs. wireless; handheld vs. headworn/earset. Let's take a quick look at those options.
DYNAMIC VS. CONDENSER
In the dynamic vs. condenser debate, here are the most important things to consider: dynamic microphones are typically more rugged, less susceptible to plosives, and afford more gain-before-feedback (GBF). Condenser mics, however, are more “detailed,” but also may pick up more unwanted sounds around them. If the increased clarity and detail are your primary concerns (and you don't have to struggle with the other issues just mentioned), consider condenser elements. They really can sound great on some vocals. For many folks, though, dynamic elements are simply easier to work with. Ultimately, it depends on what sounds good to you and what works.
DIRECTIVITY
When it comes to the directivity of the mic (patterns such as cardioid, super- and hyper-cardioid, and omni), here's what you need to know:
The omnidirectional pattern (see figure 1) picks up equally in all directions and sounds the most natural. However, most of the time in live sound we don't want that. We usually want to reject neighboring sounds for two reasons: 1) to eliminate bleed from other instruments and therefore to keep the intended sound isolated, and 2) to eliminate or reduce the chances of feedback (i.e., to have better gain-before-feedback).
That leads us to the most common directional pattern, cardioid (see figure 2). A cardioid microphone will reject sounds directly behind it. This is great if you're using monitor wedges and the mic is pointed away from them. A couple of similar variations, super- and hyper-cardioid (see figure 3), have some pickup behind them, but have better rejection to the side. The choice depends on where the monitors are relative to the mic, and also any nearby sources of sound you're trying to reject.
WIRED VS. WIRELESS
I firmly believe in staying wired whenever possible. Nothing beats the reliability, sound quality, and price of a microphone cable when compared to a radio link. When you do need wireless (and sometimes there's no practical way around it), buy good products. The good stuff is advertised here, so that can help you narrow down the choices. Many folks in church production feel that saving every possible dollar is good stewardship. I'd suggest you consider it more like this: spending every dollar wisely is good stewardship. To me, that means not spending the money if there isn't enough to buy the right product. Otherwise, you may be throwing your money away at something that won't work well or needs to be replaced sooner than anticipated. Considering that the RF landscape keeps changing with new FCC bandwidth allocations, having flexible, higher-quality RF products is more important than ever.
THE BOTTOM LINE
Finally, remember the old sound adage, “If it sounds good, it is good.” Ultimately, your ears simply need to tell you if you like the way a mic sounds. No written specification sheet or marketing literature can tell you that. If you just need a simple recommendation for a good, standard vocal mic, then the Shure SM-58 will fit the bill. But make an effort, if and when possible, to hear other vocal mics. If you can, borrow or rent some and try them out for yourself.
MIC TECHNIQUE
To get a successful vocal sound out of a vocal mic, a couple of conditions must be met: 1) The vocalist must use the mic properly, and 2) The vocalist must be able to hear a reasonable monitor mix with the right amount of themselves. Too much of their own vocal and they'll hold back; too little and they'll overexert themselves. In either case, you're going to have an unhappy vocalist (who will probably be off pitch) and the mix will suffer. Spend some time making sure they're comfortable, and that usually involves listening to their monitor mix at some point.
That leaves us with mic technique. Here's what I recommend: have the vocalist hold the mic no more than a couple of inches from their lips. You may even want to have them rest the mic on their chin (easy rule for them to remember) or touch the grill to their lips (if you sanitize it before and afterwards, or if it's always dedicated to them). Unless they are very loud, they probably won't distort the microphone this way (although you may need to adjust the transmitter gain on wireless mics). You will, however, get great gain-before-feedback (GBF), and this translates into a better experience for front-of-house and monitors. Small changes in distance have a significant impact on GBF, and you usually want as much as you can get.
A side effect of having the microphone this close will be the increased low end (due to proximity effect; something directional mics exhibit at close range). You can simply EQ this out, or leave it if you like it. Plosives may also be more problematic at that close range, so you might have to find a compromise between being close enough for good GBF, and just far enough away to avoid plosives. Or, you might need to add an external windscreen.
You may also want to discourage vocalists from “working the mic” unless you think they are great at it. It often does more harm than good (most vocalists overdo it); you're probably better off using a combination of light compression and riding the fader. Even some of the most experienced vocalists I work with don't get it right, and it makes it harder on the engineer.
PROCESSING
You'll probably find, like I have, that the low end from a vocal mic is not usually helpful information. Therefore, I recommend using a high-pass filter on your vocal channels (actually, I use this on almost every channel in live sound). If you have the option to choose the frequency, you might start at 120 Hz or so and go up or down from there. Try to find the spot where it doesn't hurt the vocal but cleans up the low end of your mix. You'll almost always get more GBF that way, too. Don't be afraid to twist that knob until it sounds right—we get too caught up sometimes in what we think the setting should or shouldn't be, rather than just using our ears.
In almost all vocal situations, there is some buildup in the midrange, typically somewhere in a three-digit frequency. While this will be different for every situation, the idea is to try cutting somewhere in that midrange territory to see if it cleans up the mix for you. This will be particularly helpful with multiple vocalists. Use the boost-sweep-cut technique if you have fully parametric EQ: first, boost a band perhaps 6 dB; then, sweep the frequency control up or down until the problem is accentuated; then, turn the EQ gain adjustment into a cut. You've probably found, like me, that the most useful EQ changes tend to be cuts, since there's often more sonic information available than we want or need in a clear mix.
When compressing vocals, you've got to strike a careful balance. On one hand, if you don't compress much or at all, you may be chasing the fader too much trying to keep the vocalist in the right spot in the mix. On the other hand, you can squash the life out of something with too much compression. Overcompressing often leads to feedback, too, since you then have to raise the level to compensate for the gain reduction. While it is beyond the scope of this article to talk about specific compression settings, I can offer you a general perspective: a few dB of gain reduction on a regular basis is probably fine. If the vocal is constantly lighting up the gain reduction meter during moderate moments, or you are frequently doing more than, say, 6 dB of gain reduction, you may need to reevaluate your compression settings. That doesn't mean heavy compression is automatically wrong: there have been times when I've had well over 10 dB of gain reduction going on with a vocal, but you simply need to question whether or not it's needed. Adjust the threshold and ratio so that it kicks in some during normal singing and only goes crazy if they scream. Beyond some reasonable amount of compression, ride the fader. You really should be doing that on a constant basis, anyway.
There are plenty of good resources online that explain EQ and compression techniques, and there are plenty of great forums for discussion, so a little time researching and experimenting can be well spent.
CONCLUSION
We can talk about vocal mics a lot, but there's nothing like listening. Every time you visit another church, or have a chance to try a different mic out at yours, take that opportunity. Listen for clarity without need for excessive EQ; immunity to plosives; rejection of unwanted sounds; and, just overall, whether or not it sounds good to you. In the end, that's all that matters.
