1. Don’t use a stage mic in the studio
Now, recording lore is full of stories of how this-or-that famous singer always records with his trusty SM58 (the classic $99 hand-held standard club mic), and still manages to sound great. And it’s probably true, at times—certainly many live mixes have vocal tracks that were taken in with this (or another equivalent) workhorse dynamic mic—I’ve mixed quite a few myself, and I thought they came out fine. But despite this, the SM58 and its ilk won’t really provide the best sound quality for a studio recording, up against other carefully-recorded instrument tracks. While stage dynamics sound ok in a busy mix, if the vocal is more isolated, or accompanied (even in parts) by a more minimal arrangement (solo acoustic guitar or piano, for example), the dynamic’s lack of clarity and air (openness) will be a limitation, and their often-slightly nasal quality will be more apparent. You can EQ for tone, but you can’t add clarity and air after the fact. That’s why most recordists use a studio-standard large-diaphragm condenser for vocals—not only do these mics have the desired open-ness, but their tonal balance is often optimized to help the vocal float effortlessly above the mix, with a minimum of fuss or EQ needed.
2. Don’t choose the mic strictly based on brand-name or $$$ cost
Despite my recommendation above, you shouldn’t choose your (condenser) mic based solely on its pedigree—a well-respected brand name or a high price tag. While those criteria will get you an excellent mic for vocals—no question—the choice (when there is a choice) of a particular mic should always be governed by how it sounds with the particular vocalist you’re about to record. That’s why, in bigger studios, you’ll often see engineers set up a forest of half a dozen mics around the vocalist and do a test recording to see which is better for that singer in that room on that day. Just because you have access to a Neumann U87 (or some other classic vocal condenser), doesn’t mean it’s automatically the best choice in every instance. I’ve used my U87 on the majority of vocal tracks I’ve recorded, but with some singers it can be a bit bright or harsh. I remember one vocalist who just sounded too thin and edgy on that mic, but ended up sounding perfect—warmer and fuller—with a much more inexpensive condenser from a less-well-known brand (which cost about a tenth of the price of the Neumann!). So the moral is, whenever you’ve got a choice, always let your ears be the ultimate guide.
3. Don’t position the vocalist too close
While you may be tempted to have the singer get right up on the mic—especially if there is other sound in the room that you want to avoid leaking into the vocal track—this is not the best idea, especially with typical studio large-diaphragm condensers. These mics need a little distance—around 6” to a foot or so—to achieve their characteristic air and openness, and the best frequency balance.
Get too close to a directional mic (directional—cardioid—response is the only pattern available in many good but slightly more budget-conscious vocal condensers) and you’ll suffer from excessive proximity (low-end) boost, which may sound great for radio announcers, but is not so great for most vocal parts. As long as the room is not overly ambient or peaky, and reasonably well-isolated from unwanted sound (other instruments or outdoor noise) you’ll get a more natural tone and a more open, three-dimensional quality with the vocalist at a proper distance.
4. Don’t let the vocalist move around too much
One potential downside of having the vocalist maintain a little distance from the mic is that if he/she moves around too much in performance at that distance, you may be able to hear the vocal tone and ambient level change in the recording—an unwanted distraction, that may be difficult to fix later (especially if the mix is relatively dry). A little rhythmic swaying will probably be fine, but a lot of english may turn out to be problematic (that could be partly why that famous singer from tip #1 insists on his favorite hand-held). If you do run into this issue, it needs to be handled delicately—this is where your studio savvy and that psychology degree your mother made you earn (you know, “as a fallback”) will come into play. You don’t want to intimidate the singer or put a damper on his/her enthusiasm, but you also don’t want to end up with a fatally-flawed take of an otherwise great performance. A gentle request or reminder, and maybe an X on the floor (with gaffer’s tape) can help the singer stay in position.
5. Don’t depend on the mic’s own popscreen
Even though all mics suitable for vocals have a built-in popscreen (windscreen), this typically is not enough to guarantee freedom from p-pops—technically called “plosives” (those distracting thumps that often happen on the letters “p” and “b”, and are hard to get rid of). Blasts of wind from the singer’s mouth shake the mic’s diaphragm, and even at recommended distances, they can still occur. Two solutions present themselves. First, employ an extra stand-mounted pop filter an inch or two in front of the mic—this will offer another layer of protection, usually with little or no significant effect on the tone. And second, angle the mic so the singer is just a tiny bit off-axis—this can direct those blasts of air above, below, or to the side of the diaphragm, avoiding those problematic “p”s.
6. Don’t overload the ADC
Even when you’ve got all the acoustic and mechanical aspects squared away, the final step in the recording chain can still trip you up. In the days of analog tape, engineers used to regularly push input levels (to keep the audio above the noise floor), and if the meters went a little into the red, the resulting gradual tape saturation actually contributed a degree of analog warmth. But with today’s digital recording, you absolutely can’t let the input signal hit the red and overload the ADC (the Analog-to-Digital Converter) in your audio interface. Digital media don’t saturate gradually—they clip hard, for a spiky distortion that can manifest itself as loud pops and/or a harsh edge.
While there is specialty software that can be used to try to remove this digital clipping, it’s typically not available in the average small/home studio, and there’s no guarantee it would succeed anyway (even it it did, you’d likely lose the artists’ confidence if they hear their wonderful takes played back with nasty digital spikes). You could compress/limit the audio during recording, but if you’re not experienced at that, you may find you’re not always happy with the results. A better strategy would be to keep the level more conservative—remember, the current standard 24-bit digital resolution has no audible noise floor, so levels don’t need to be pushed. An incoming vocal signal level whose peaks max out between -12 and -6 dBFS is a healthy recording level, with plenty of headroom (safety margin) for the occasional dramatic shout or belted high note. Though the resulting wave may look a little small in the DAW, you can always crank it up later, if need be, with no negative consequences.
A little attention to these most common pitfalls should insure the best vocal recordings. If you get a good clean, dynamic signal on the way in, then when it comes time to mix, you’ll find you’re already halfway there.