HEADS UP
When positioning mics on drums, especially close mics, a good guideline is to angle the mics and avoid forming parallels between mic diaphragms and drum heads. This technique helps to prevent adverse phase interactions caused by reflections between the head and the diaphragm.
On the snare drum, start with the mic above the head, angled downward 30 to 40 degrees toward the head, with the diaphragm roughly even with the rim of the drum (see Fig. 4). The trick is to find the balance between what sounds best to the mic, what provides the best rejection of unwanted sounds, and what's comfortable for the drummer. This can take some doing. You can't just position mics in a haphazard or formulaic way and expect to automatically capture the best sounds.
Note first how any (unmuffled) drum's response varies across the head (see Fig. 5). The sound is “ringy” and high pitched (rich in high harmonics) near the rim, and it is most resonant exactly between the rim and center. At dead center the sound is driest, and thus strongest on attack (this is because the resonance gets dampened by cancellations along the head).
The drummer has primary control of these tonal variations, by striking the head in different spots. But the mic, in addition to hearing what the drummer is doing tonally, hears the drum differently depending on which of the three areas it is focused on.
When close-miking with a dynamic, you can also affect how much “air” you put around the drum. Many engineers automatically position snare and tom mics as close as possible to the drum head, often with the mic angled steeply so that the cap points into the head close to the rim. That may give better isolation, but capturing the best sound from the drum is ultimately more important than reducing leakage.
Typically, putting the mic too close tends to choke the sound. The drum will sound fuller and more natural if you give it a bit of breathing room. Simply pull the mic back an inch or so, and reduce the angle of attack. That will open up the sound and increase attack simultaneously (assuming the mic is aimed more at the center of the head). And you might even find that the extra leakage works to integrate the sound of the kit.
To sum it up, you have three things to play with when listening for the sweet spot: the angle of the mic, how close it is to the drum, and where it's pointing. Whenever possible, make final mic-position tweaks based on what you're hearing, rather than on what you're seeing. Just close your eyes and let the sound guide where you position the mic. (A tip for those recording in the same room in which the gear is set up: wear closed-ear headphones and have the drummer play softer than usual, at least to get started. That gives you a fighting chance of determining the best place to put the mic.)
Another way — more tedious, but also more telling — is to record identical passages of drumming with the mic in a slightly different position each time. Three or four variations is usually sufficient. Afterward, compare the tracks on the monitors.
HIGH FIVE
If you have a fifth mic at your disposal, common practice would dictate putting it on the hi-hats. And depending on the song you're recording and the emphasis you're going for, the hi-hats might well be the best place for it. But unless the song cries out for separately miked hats, consider using the fifth mic to record room sound, particularly if you're loving the sound of the drums in the space.
A condenser mic with an omni or a figure-8 pattern is usually best for room miking, but try whatever you have. Sometimes a funky old dynamic can capture a hip ambience. No matter what mic you use, though, the mix engineer will probably be thankful; a good room track can add that extra something special to the drum mix.
Assuming that you already have one or more overhead mics on the kit, try positioning the room mic on the other side of the room, far from the drums. Walk slowly around the space while the drummer plays and listen — with ears only at first — for an appealing balance of drum elements (lows, mids, and highs) and ambience (room sound). After finding the general good area, put the mic there and fine-tune the position while listening through closed headphones (or the control-room monitors if you have a control room and an assistant). Move the mic around a lot and listen — it might even sound best aimed into a wall or a corner.
Experiment with putting the room mic up near the ceiling and down close to the floor. Not surprisingly, many pro engineers prefer a stereo pair of mics for capturing room sound. Again, it all depends on the sound you're going for and the gear that's available.
Of course, depending on the song, that precious fifth mic might be better used elsewhere — for example, on a tom that is played repeatedly as part of the groove. If you use it on the hi-hats, be sure to position the snare and hat mics (assuming they're directional) so as to maximize isolation between them. You do that by taking advantage of each mic's null point, which is the sound-rejecting area directly behind the capsule (see Fig. 6). The reason you want maximum isolation is so the two tracks can be processed differently in the mix without affecting each other too much. It's frustrating to bring up the hi-hat track and have it ruin the snare sound.
When miking hi-hats, position the mic so it's looking down toward the bell of the top cymbal, or just to the edge of the bell, at a slight angle. This emphasizes the clear highs coming from the bell area, and keeps the diaphragm clear of air blasts coming from between the cymbals. It also avoids the gonglike quality that cymbals typically produce when miked near the edge.
In addition, keep the hat mic a safe distance from the top cymbal. Placing the mic any closer than three inches to the cymbal will cause you to risk picking up a weird-sounding phase change as the cymbal moves toward and away from the mic. You also risk the cymbal crashing into the mic. Some drummers keep their hats quite loose and with a fair space between the cymbals, so pay attention to the throw of the hat cymbals as the drummer plays them hard. To keep it safe, position the mic capsule at least five inches above the hats, angled slightly away from the snare drum to reduce leakage (see Fig. 7).
Finally, when recording hi-hats, be sure to engage the mic preamp's highpass filter (assuming it has one). Many hat cymbals are quite thick (especially the bottom one) and produce an unpleasant low-frequency roar that is better filtered out from the start.
NO LIMITS
If the number of mics, preamps, and tracks is not an issue, the logical next step is to mic each tom. But before doing so, it can be useful to get a good overhead sound first. That way your first impression is how the kit sounds as a whole — a good foundation to build upon. From there you can supplement the sound by adding the various close mics.
Remember to keep the null points in mind when positioning tom mics. As with the snare, start with the mic at about a 45-degree angle, pointing more or less toward the center of the head. Then move it around from there while listening for the sweet spot. You might need to go in at a steeper angle to increase isolation, depending on sight lines of the mics.
Here's a tom-tom recording tip that will serve you well at mixdown. In the course of a typical four-minute song, the toms might be struck only once or twice each — not much to work with when you're trying to dial-in compression, EQ, and other processing. Therefore, on a separate section of tape (just before or after the song), record the drummer playing a dozen or so whole notes on each tom, making sure the hits are at the same level as those played in the song. At mixdown, you can loop this section to work with while processing the toms. (If you're recording to a DAW system, this won't be necessary, because you can simply loop one of the sections featuring the toms and have it play repeatedly while you're tweaking.)