This month we're going to cover the nitty gritty of drum recording and that's mic placement. Now if you have a great sounding kit, an excellent drummer, and a terrific sounding room, chances are you're going to have to work pretty hard to screw up the sound, but that doesn't mean that getting a drum sound is easy even under the best of conditions. That being said, there are a number of things that you can do that will capture the best sound possible almost every time. Before we cover those, let's talk about some things that can make the drums sound bad (aside from drum tuning and the player).
Also available in this series:
- Recording The Drums – The Song’s Heartbeat – Part 1
- Recording The Drums – The Song’s Heartbeat – Part 2
- Recording The Drums – The Song’s Heartbeat – Part 3
- Recording The Drums – The Song’s Heartbeat – Part 4
- Recording The Drums – The Song’s Heartbeat – Part 5: It’s All In the Mix
Phase Cancellation - The Drum Sound Destroyer
One of the most important and overlooked aspects of drum miking is making sure that the mics are all in-phase. This is really important because with only one out-of-phase mic, the recording of whole kit will never sound right, and if not corrected before all the drums are mixed together, can never be fixed.
So just what is phase anyway? Without getting into a heavy explanation, it just means that all the microphones are pushing and pulling to the sound pressure of the drum kit together. If one mic is pushing while another is pulling, they cancel each other out. Check out the diagram of Figure 1.
In Figure 2, both mics are pushing and pulling together. Their signal peaks happen at the same time as does their valleys. As a result, their signals reinforce one another.
Acoustic Phase Cancellation
There are two types of phasing problems that can happen - electronic and acoustic. An acoustic phasing problem occurs when two mics are too close together and pick up the same signal at the same time, only one is picking it up a little later than the first because it's a little farther away. In Figure 3 the cymbal mic will also be picking up some of rack tom, which can lead to an out-of-phase condition.
With acoustic phase problems, the sounds won't cancel each other out completely, only at certain frequencies. This usually makes the audio of the two mixed together sound either hollow or just lack depth and bottom end. Keep in mind that if you listen in mono and on a single speaker, it will be a lot easier to hear if anything is out of phase.
In practice acoustic phase cancellation is rarely an issue because the mics may not be identical and the gain of each is different, so you won't hear anything cancel out completely. But if something just doesn't sound quite right, this is the first thing to look for because it takes so little to fix. Sometimes just moving the mic an inch or two or changing the slightly direction that it's pointed can clean it up fast. In this case, if the cymbal mic is pointed away from the tom and moved to the other side of the cymbal (it should be over the bell of the cymbal), any phase problems between those mics will be probably be eliminated.
Electronic Phase Cancellation
While most things that you read will tell you how to avoid acoustic phase problems, we have to really take a look at the electronic phasing of the mics as well. The term for this is really called electronic "polarity" instead of phase, but you end up with a 180° phase shift so the term is not altogether incorrect.
Why would there be an electronic phase problem? Almost all of the time it's because a mic cable was mis-wired, either repaired incorrectly or originally wired incorrectly from the factory (which is rare). There are two ways to check the electronic phase.
Checking Phase The Easy Way
There's a very easy way to check mic phase of the kit, although not as precisely as method #2 shown later.
After you get a mix balance of the kit together, flip the phase selector on each mic channel one at a time either on your console or on the DAW. Whichever position has the most low end, leave it there. Do this on every mic in the kit (select the overhead and room mics in a pair, but check the left mic against the right as well).
Checking Phase The Slightly More Difficult Way
This method takes a bit more work, but you'll know for sure if you have a mic cable that's wired backwards. Also, you really have to have another person with you to make this work. It's a two-man operation.
First you have to pick a mic and make it your "reference". Any mic on the kit will do, but it's easier to pick an overhead or a mic that can easily come off the stand.
Now take your reference mic and put it next to another mic on the kit, say the kick drum mic, as in Figure 4. Make sure that each mic is at the exact same volume level. Now have the person holding the mics talk into them while you switch the phase selector on either the console or DAW. Again, choose the selection that sounds the fullest.
Do this to each microphone. Any channel that has it's phase selector different from all the others has a mis-wired cable. Make sure you mark it so you don't have the same problem again!
Now you might be wondering, "How was my cable mis-wired?" This usually occurs when a studio is being wired and there's a lot of custom wiring done. Although it doesn't happen often, it doesn't take much too much for pins 2 and 3 on an XLR cable to be wired backwards because you can't see properly in the low light, it's too late at night or too early in the morning before the coffee kicks in, or other such easily overlooked procedures. If all you're using is store-bought cables, this will probably never be an issue. But as soon as you introduce some custom wiring or a cable repair job, you better do a phase check. All it takes is one cable anywhere in the system out of phase (or accidentally selected on the console or DAW), and the kit will never sound right and the sound can never be resurrected.
Another rare possibility is that the mic itself is purposely wired with the opposite polarity, but this usually occurs with vintage mics made before the 80's. By the 90's, every manufacturer observed the same standard, so new mics won't have this problem. Always worth checking though.
Times When You Might Want The Phase Reversed
There are times when you should definitely consider flipping the phase before you start mixing. As we said before, there may be some acoustic phase issues as well because a mic may be farther away than another yet it's picking up the same source. In the following cases, the phase is usually flipped to overcome an acoustic phase problem.
- An Under-Snare Mic - As we'll discuss a bit later, the under-snare mic should just about always be flipped out-of-phase. Most engineers will flip the phase while recording so there's no uncertainty afterwards.
- Room Mics - Depending upon where they're placed, how much room reflection they're receiving, and how high they're used in the mix, sometimes the room mics sound a lot better if the phase is reversed.
- Overhead Mics In Extremely Rare Cases - Once again, it depends upon how high they're placed above the kit, what kind of reflections they're receiving from the floor and especially the ceiling, and if they're the main sound of the kit, but on rare occasions it might sound better (meaning fuller) if the phase is flipped.
Leakage Is Your Friend
Acoustic spill (known as leakage) from one instrument into another's mic is many times thought of as undesirable, but leakage can and should be used to enhance the sound instead of avoided. Many production and recording novices are under the mistaken belief that during a tracking session with multiple instruments, every track recorded must contain only the instrument/source that the mic was pointed at. Since that's pretty hard to achieve unless everything is overdubbed, why not just use the leakage to embellish the tracks instead?
Instead of trying to avoid the leakage, great attention should be taken to the kind of leakage being recorded rather than trying to eliminate it. Leakage can be used as a sort of glue between instruments in much the same way that instruments magnify one another in a live situation, but not if it sounds phasey and hollow.
So, when tracking multiple instruments, try to keep the players and their gear as close together as possible. Not only will it help the players communicate, but the leakage will have more direct sound than room reflections, which will sound better. This might make any fixes clash with the basic tracks, so it's best to have keeper tracks from all the instruments (or cut and paste from other takes) in order to get the desired effect.
Placing The Kit In The Room
One of the most overlooked items during recording is placement of the kit in the recording room. Most times, placement of the instrument will be either random or whatever's convenient, but where the kit sits plays a big role in how your recording will sound since the environment is so much of the total sonic package.
If you do nothing else, positioning your kit in the best acoustic place in the room will do wonders for the sound. What you're looking for is a spot where the drums or acoustic instrument sounds relatively live without any of the room cancellations. Try these following steps to find the best room placement:
- It's usually best to stay out of a corner. The corner normally causes "bass loading", meaning that the low frequencies will be increased causing your kick and floor tom to be louder than the other drums. This can also lead to increased ringing and snare buzzing. That being said, don't rule the corner out without trying it first since the extra fullness of the kick might be just the thing you're looking for.
- Test a room by walking around and clapping your hands. That's a good way to find a place in the room that's has a nice even reverb decay. If the clap has a "boing" to it (a funny overtone), then so will your drums so it's best to try another place in the room. If you can't find a place without a boing, place the drums where they sound the smoothest and put some padding or something soft on one side wall to break up the standing waves.
- Ideally, you don't want to be too close to a wall. The reflections (or absorption if the wall is soft) can change the sound of the kit. The middle of the room usually works best.
- Ideally, you want the place in the room with the ceiling height is the highest. If the ceiling is vaulted, try placing your drums or acoustic instrument in the middle of the vault first, then move as needed.
- Whatever you do, stay away from glass if you can. Glass will give you the most unwanted reflections of just about any material. If you have no choice because of the way the room or the band is situated, try setting up the kit at a 45° angle to the glass.
- Put a rug under the drums. Not only does a rug give the drummer a way to anchor his drums a bit, but if stops any reflections off the floor, which almost always have a negative impact on the overall sound.
Mic Placement On The Drums
There are a number of ways to mike the drum kit with a wide variety of microphone combinations, but what we'll go over is the essence of getting the drum sound. Forget about the make and model of the mic, because what works on one drum kit, for one drummer, for a certain kind of music, for one engineer, in one studio, won't necessarily work in another. Your fooling yourself to think that you can get a certain kind of sound from a certain drum because you're using a certain kind of mic. It probably won't happen. There are good places to start though, and we'll try to provide a reference point, knowing that you'll change it out in a second if it doesn't approach the sound you like.
So let's look at each drum and what determines what the mic will hear, rather than just a random placement.
Kick Drum Mic Placement
The kick drum is the most unique drum in the kit because it's sound has to have the right combination of definition and girth, so it usually takes two mics to accomplish the task of getting a balanced sound. What makes it even more unique is the fact that it might have a head on the front, no head at all or one with a hole in it.
The first thing to realize is that a kick with a front head will not give you the tight sound of a kick without it no matter how hard you try. They're two different animals. Let's look at a kick without a front head or one with a hole in it first.
Inside Kick Mic
The definition from the kick drum comes from its mid and upper mid frequencies and those come from the beater. For that reason, we use an "inside the kick drum mic" as the definition mic and the closer it gets to the beater, the more definition you'll get. Most of the time you don't have to place it inside the drum; right at the edge of the shell should do it (see Figure 5). If you need more definition (more of the beater), place the mic further into the shell.
For a kick drum without a front head, place in the center of the drum level with the beater and at the edge of the drum about the same as in the case with a hole in the head (see Figure 6).
Muffling The Kick
Most of the time a kick drum sounds better and is easier to tune if it has a bit of muffling. Here are some rules of thumb to follow:
If the drum has two heads
- Place a down pillow, bath towel or blanket so it's touching both heads. If you want a deader sound, push it more towards the beater head.
- If the drum isn't punchy enough, increase the muffling or try a different pillow, towel or blanket.
If the drum has only a beater head
- Place a pillow, bath towel, or blanket so it's lightly touching the head. If you want a deader sound, push it more towards the beater head.
- If the drum isn't punchy enough, increase the muffling or try a different pillow, towel or blanket.
The Outside Kick Mic
The "girth" part of the kick drum sound comes from the outside mic and this is where engineers get into trouble. No matter what, you're going to have leakage of the kit and maybe some other instruments into this mic, so get it out of your head that it'll be clean. Sure, you can build a tunnel of blankets around it, but that will change the sound (because the leakage will still be there and it might sound worse) and maybe not for the better, so just go ahead and record it without the blankets and use the leakage to your advantage as we said earlier in the post.
For the placement, put your hand about six feet in front of the drum and move it until you just feel the puff of air when it's struck. This is where you place the outside mic. I like to place it directly in the center of the drum if it has no head, and behind the inside mic if there's a hole, but because each drum is different, you'll have to move it from left to right in front of the drum a bit to find the sweet spot.
You won't have to worry about acoustic phase with the inside mic because they'll probably be beyond the 3 to 1 distance, but their recording different things too; the inside mic getting more of the beater and the outside mic hearing more of the total kick drum sound (see Figure 7).
Many drummers play better with the front head on the bass drum because they can feel the back pressure from the front head when they hit it. If you have a kick drum mic with a head, you'll treat the placement just like you did for the outside mic without the head. Where you feel the puff of air, that's the ideal place. Need more definition? Try placing another mic on the beater side of the drum aimed at the beater on the far side of the snare It's messy and you'll have some leakage, but you might get the sound you're looking for.
Lately there's been a return to using ribbon mics like the Royer 121 on the kick drum. Ribbons generally sound great on drums but last about two drum strikes before the ribbon is torn to shreds. Modern ribbon mics like the Royers can take a lot more abuse, but are still subject to blowout if the air plosive is too great. There is a trick to using them on the kick however, and that's to tilt the mic so it's aiming at the floor about half-way between the mic and the outside rim of the kick (see Figure 8). This works great, getting the best out of the microphone with endangering it.
The Subkick Mic
Over the past 10 years, subkick mics have become very popular, first as a custom built unit and then as a commercially available product from Yamaha. The subkick gives you that extra octave on the bottom below 60Hz that you might be having a difficult time recording. If you have a well-placed outside kick you probably won't need a subkick but it can come in handy if there's so much leakage that it's impractical to use an outside mic, since the subkick is pretty clean. If that's the case, place the subkick on the edge of the kick drum shell away from the inside mic (Figure 9). Why there? First of all, the one from Yamaha is pretty large, so you don't have much room to play with on the kick. Bit it's always a good idea to maintain the phase relationship and keep the 3 to 1 rule in effect if you can.
If you use an outside kick mic or a subkick mic, be judicious with its use during the mix. It sure is tempting to crank it up and get this massive bottom, but that much low end won't leave much room for anything else with a lot of lows like the bass and floor tom. In practice, a level of about 10% of the inside kick mic is about right.
In the next post we'll look at some miking techniques for the other pieces of the kit.