If you missed the previous installment, here's a quick catch-up: we're taking a tour of the most widely used microphone techniques for recording an acoustic drum kit. The techniques are presented from a practical standpoint: there are audio samples from more than 30 mics, ready to download. Combined with one another, the various files demonstrate many of the common methods for capturing this instrument. The audio examples were recorded in a top-notch environment, PKO Studios, where we had the pleasure of working with Caco Refojo (studio engineer) and Rober Aracil (professional drummer).

This time it's the turn of two-mic stereo techniques, three and four mics, and multi-mic recording... Head to the ISP website, download the samples for this second installment and let's get started.

Two Mics in Stereo
The previous article showed how the step from using one mic to using two usually happens naturally when you want to reinforce the sound from an OH with an additional mic on the kick drum. However, moving to two mics can also be motivated by the desire to capture a stereo sound of the instrument, for which any of the usual stereo mic techniques can be used.

For example, mics #3&4 are two Neumann KM184s in XY, placed above the kit about 130 cm from the snare's top head. They give a balanced sound of the drums, with a solid stereo image.

Moving on to #6&7, this is a spaced AB pair made up of two Neumann U67s placed above the kit at about 1 m high. If you pan these two mics 100% left and right, you'll find that, as expected, the stereo width is much greater than with the XY technique.

However, this comes at the expense of opening the door to possible phase problems when the spaced AB pair is summed to mono, so when physically placing the mics for this technique you need to pay special attention to how they behave when panned to the same position. It's also common to narrow the spaced pair a bit; at 100% wide it gives an image of the kit that may be too wide or unnatural in some cases. This also helps the snare appear more centered in the stereo field. Try slightly varying the level and pan between the two channels of the AB technique until you get a balance you like.

You'll notice the instrument balance differs from the XY technique, partly because the distance from the kit's elements to each mic has changed. For example, the AB technique reproduces the balance of the different toms better, since one of the mics is closer to the outer tom (kit details in the previous issue). The difference is especially noticeable in the intro and in the final chorus, where the 18" tom comes into play.

There are also differences in the tone of the two techniques that are due not only to position but also to the type of mic, both in diaphragm size and in the mic's electronics (the KM184's solid state vs. the U67's tubes). To better evaluate these differences, set the pan of the spaced pair to around 40% and switch back and forth between one pair of mics and the other.

Moving on to other techniques, another way to get an overall picture of the drums is usually to place a stereo pair at the height of the drummer's head, or behind them.

In the first case, you can use an ORTF with the mics near the drummer's head (from behind, making sure not to get in their way), which gives an image similar to how the player hears their own instrument.

The other technique would be to use a spaced AB pair from behind the drummer, on both sides. For this text we chose the second option, because it lets us compare its result with that of the other AB (mics 6&7). These are mics 8&9 (OH_REAR), which again give the view of two U67s, but this time placed behind the drummer, slightly farther away (130 cm). The difference in position and distance produces tonal variations in all the instruments, especially cymbals and toms.

As we'll see in the Multi-Mic Recording section, it's common to build the modern drum sound from the OH mics.

If you compare these three stereo techniques (after matching the level between the tracks), you can hear how the starting point of the drum sound would change just by selecting one technique and mic type or another.

Moving on to the stereo room mics, the pair formed by microphones #15&16 illustrates a Blumlein technique, with two Sony C48s placed at a height of 140 cm and almost 4 m away from the kit. The result is a very balanced, natural drum sound with a very solid stereo image.

The next room pair is made up of two Neumann M49s in a spaced pair, with the mics at a height of 220 cm and almost five meters from the kit (the distance between them was about 270 cm). Because they're so far apart, the mics pick up two very different signals. This gives a wide stereo image, but it can be excessive in some cases: it's also common not to open this AB pair to 100%.

Note: Whether a channel is called “L” or “R” depends on how you look at the drums, from the musician's point of view or the audience's. Rename the files if necessary to suit your preferences.

Three Mics
Similar to the step up to two mics, the step to three often comes from using a stereo OH pair to pick up the instrument's overall sound, plus a spot mic on the kick. Try, for example, combining the XY pair (mics #4&5) with the different kick mics (#19, #20, #21), to once again hear the nuances each kick position brings.

Conversely, select one particular kick mic and alternate between the XY pair (#4&5), the overhead AB (#6&7), the rear AB (#8&9), the room Blumlein (#15&16) and the room AB (#17&18) to see how, just by changing mic type and position, you can drastically change the sound of the same instrument: without touching a single processor (EQ, compressor, etc.), each combination can sound more modern, vintage, aggressive, close, distant, warm, and so on.

A very well-known three-mic technique is the Glynn Johns, named after the famous 70s recording engineer who developed it (Google his name to learn about his impressive career in detail). This technique places one overhead mic above the snare and a second mic, the side mic, in the area of the floor tom (to the drummer's right, also aimed at the snare), both at the same distance from it. Panned wide, this combination gives a lovely image of the kit that, reinforced with a kick mic, makes for a very simple, effective and natural way to capture the whole kit.

Because of the tom pattern being played as an example, Caco suggested switching to a variation of the Glynn Johns known as Recorderman. The variation is in the position of the side mic, which is also placed the same distance from the snare as the overhead, but from behind the drummer (on the right). This gains definition on the toms, which is very suitable here given the type of pattern. You can hear the Recorderman technique with the mics from the previous installment, #2 (overhead) and #3 (side); add any of the kick mics to taste. An impressive sound with just three mics...

You can vary it even more: try replacing the kick mic with one of the front-of-kit ambient mics (#10, #11, #12), especially the Manley. As mentioned in the previous issue, these mics tend to have a more pronounced kick sound than the overheads so, although you lose some of the immediacy of a close kick mic, you gain overall ambience with the front mics.

If we go back to the mono concept, there are also plenty of three-mic options. For example, the ribbon OH #1 can benefit from a bit of room (#13, #14), and a reinforced kick with #20. In general, try different combinations with one of the kick mics, one of the overheads (#1, #2, #3) or front mics (#10, #11, #12), and one of the mono rooms. Each type of mic gives a different color because of its position and transducer (ribbon, condenser, etc.), so combined they produce many different images and impressions of the same instrument.

Four Mics
You may have already thought of it: in some of the combinations we've tried so far, you might miss some definition on the snare, or the ability to have more control over it. A fourth element common in the Glynn Johns and Recorderman techniques is a reinforcement mic on the snare. In fact, these techniques are sometimes considered "four-mic" setups, since the snare spot mic is included by default.

Microphone #22 is the famous Shure SM57, placed about 6 cm above the top head, at rim height (slightly inside it), and pointing toward the center of the head. A classic, very effective. For comparison with the sound a dynamic mic gives, a condenser was also placed next to it (mic #23, an Earthworks SR69). You can hear the difference in tone between the two, although it would be more obvious with a different pattern (for example played with brushes), where the condenser would bring much more detail than the dynamic.

Open mics #2&3 (Recorderman) and gradually add a kick mic and a snare mic (for example #19 and #22). Vary proportions and pans until you reach a balance you like between the different elements and the ambience and cymbals.

With kick and snare mics already available, there are many four-mic options. You can replace the Recorderman mics with any of the OHs (#4&5, #6&7, #8&9), or even with the stereo rooms (#15&16, #17&18). An interesting perspective is achieved by combining kick mic #20 with snare mic #22, and then adding mono room #14 (an AKG C12). To gain proximity and definition, you can add overhead #1 (ribbon). Another interesting option is to combine mics #2&3 with one of the overheads or stereo rooms.

Want the drums in the background? Open snare mic #22, add front mic #12 until kick and snare sound balanced, and add the AB stereo room (#17&18) from behind, opened to 100%. If you narrow them a bit (to around 60%) and raise their level, you'll see the drums sit even further back. In this last example, it would be very easy to go up to five mics if, for instance, you wanted a somewhat more powerful, closer kick in the mix. You'd just need to add #19 if you want a kick with attack, or one of #20 or #21 if you're after a rounder sound.

As you can see, once the possibilities for mic position and transducer type are clear, it matters little how many mics you use; just build the sound from one and then add the elements needed to get the result you want.

Multi-Mic Recording
And this leads to today's standard multi-mic setup, in which there are one or more mics for each instrument (for example, kick and snare usually have two or three mics each), along with overhead mics, front/ambient mics and room mics. That gives you a large number of options for deciding the image you want to give the drums, even if in the mixing process you opt for one path or another.

In the example at hand, with some parts of the rhythm based heavily on toms, having a mic on each tom is clearly necessary if you want to play with the toms comfortably in the mix. Microphones #26, #27 and #28 are Sennheiser MD421s on each tom (toms 1, 2 and 3, respectively). It's common to put dynamic mics on these elements although, again, in less energetic styles of music, using condenser mics on the toms can bring more detail.

Open one of the stereo OHs, add a kick mic and a snare mic, and then add the tom mics one by one (for now, panned center). Once you have a balance you like with these channels, try switching to the other overhead mics to hear the variation in sound each one provides. When stereo OHs are used, each tom is usually panned to the point where it appears in the overheads' stereo field, although as an effect you can pan them to exactly the opposite side. Again, you can see there are many possibilities: each mono and stereo OH provides a different viewpoint of the kit, and you can then add the various front and room mics to get other colors and/or add depth.

For example, in this particular case, the spaced pair #6&7 combines very well with the toms and gives a very wide image of the drums. If you add a kick mic and a snare mic you'll have all the main elements, and if you miss some brightness on the cymbals you could use one of the other overheads for that.

Add one of the front mics to give a bit more depth (in this combination, ribbon #10 works very well), and add a stereo room to give size, for example the spaced pair #17&18.

Kick Drum
It was mentioned in the previous installment that it's now common to use two or more mics to get a defined, full-bodied kick sound. For example, mic #19 (the classic D112), placed inside the kick, picks up a sound with a good proportion of beater click, and can be seasoned with #20 or #21 to add low-end body.

The outside D12 gives a more retro sound, while the U47 is a large-diaphragm condenser widely used on the outside of the kick (another large-condenser model will also work). Because of their position, external kick mics pick up more cymbals and other elements of the kit, so you'll sometimes see them covered with blankets or EQed with a low-pass filter.

Snare
Similarly, it's common to see more than one mic on the snare, generally one to capture the top head and another for the bottom head and snare wires. Mics #24 and #25 are two mics placed under the snare. The first is a dynamic (SM57) and the second a small-diaphragm condenser (Neumann KM184). You can hear how the different transducers produce variations in the way the snare wires are rendered. Generally, the polarity of these mics has to be flipped so that they sum well with the top mic. In the audio examples it has already been inverted.

Hi-Hat and Ride
It's also common to place reinforcement mics on other elements, in case you need more control over them later. Mics #29 and #30 are AKG 451s on the hi-hat and ride respectively, two of the elements where additional mics are normally placed.

Conclusions
On the journey from using one mic to multi-mic recording, we've seen that there are a great many options and possibilities in between. Knowing all of them lets you decide which setup you'll need to get the sound you're after... Depending on the kind of song and music, the drums may be better represented with two mics than with twelve. In fact, we've already seen that with just four mics you can get a very powerful, defined and well-balanced sound... and that's with no filter, equalizer, compressor or other type of processor used in the recording. The audio files show what each mic was capturing, with no seasoning at all. In general, doing this up-front work of choosing the right mic type, its position, angle, relative phase and so on always pays good dividends in the final result.

Once you're totally satisfied with the sound of the miking, that's when you should start thinking about ways to improve on what you have... Find a mic balance you like, and then try cleaning it up a bit with filters, adding some EQ, compression and so on. One of the advantages of recording with gear of this quality is not just how things sound naturally, but how the signal responds when it's processed!

* Photography: Pitu López