Let’s face it,
nothing beats a large, dedicated, well tuned room in which to record drums. With the right microphone setup, you can get the huge ambience of the room plus the tight sound of each drum as well. But in this day and age, it’s becoming harder and harder to find these giant spaces. There is also the cost to consider as well. Most of us home studio sound sorcerers have to rely on other means to achieve huge drum sounds. The good news is that technology has, once again, come to the rescue. Recording live drums is, in the best of circumstances, a skill that requires knowledge and practice. In a small home recording studio, the process becomes even more tricky. While recording electronic beats “in the box “ is a fairly straightforward process, setting up a bunch of microphones around a real drum kit in a bedroom or basement can open up a whole world of hurt unless you understand and follow several basic principles. Having straddled both worlds working in incredible recording studios and untreated basements – I can offer a bit of advice when it comes to getting a great sound from a drum kit when you are recording in less than optimal conditions.
Assumption #1
We aren’t going to tackle the drums themselves in this blog. A whole separate article, perhaps a book, can be written on properly preparing a drum kit for a studio recording session. We are going to assume that the drums are tuned, the squeaks and rattles are taken care of, the drum resonances compliment each other and the proper muffling has been applied – basically, that the drums are ready to be recorded.
Mic Placement
The first thing we need to tackle are the microphones. Whether you are setting up the mics in a cathedral or a closet, proper mic placement is crucial to getting the best sound out of the kit. You have several choices when setting up your mics.
Overheads
Since we are talking about less than ideal room conditions, we are going to assume that your overheads will be focused on the drums rather than a fabulous sounding drum room. Opting for two overheads as your entire mic setup is a good choice if you are looking for more of a live sound. In this case, the entire drum set is recorded as a single instrument so you want to make sure that the drums are all in tune with each other, de-rattled, and unified. This is true no matter how many mics you use, but with overheads only, it is crucial that the drums all play nicely with each other because you can’t go in later to fix any individual drum sound.
Positioning
Since you are recording in a less than perfect environment, you will need to experiment with the positioning of the overheads to find the best possible placement for your room. Once you have that, you can usually use that same setup for other sessions with minimal changes. There are several techniques you can use when positioning your overheads:
- Spaced Pair (A/B) – Two microphones are placed on either side of the kit either in front of or behind the drummer. Although this is the most popular configuration because it is quick to setup and creates a wide stereo field, phase cancellation issues can easily occur.
- XY – Two cardioid mics are crossed in a horizontal V shape, pointing towards the sound source at a 90-degree angle to each other. The angle can be adjusted to influence the stereo image. A wider angle increases the stereo field but reduces the center image. A narrower angle tightens the center image but decreases the stereo field. The XY method translates well to mono playback and phase issues are eliminated because the relationship between the mics is consistent.
- ORTF – A matched pair of cardioid microphones are positioned close together, typically around 7 inches apart and then angled outwards at 110 degrees relative to each other. This method provides a spacious stereo field, translates well to mono playback, and minimizes phase cancellation issues. ORTF is named after the French Office de Radiodiffusion Télévision Française.
- M/S (Mid/Side) – Uses two mics to create a mono signal and a stereo signal. A cardioid mic is pointed directly at the drum kit to capture the central image. This is the Mid signal. A figure-eight pattern mic is positioned perpendicular to the Mid mic to pick up the ambient sound from both sides. This is the ’Side’ mic. This method requires special processing during the mix to convert the signals to stereo. The advantage of this method is that you can adjust the stereo field during mixing. It also translates to mono well and eliminates phase issues.
Your client, if you are working with one, will usually have an opinion on overhead mic placement, but knowing how each position sounds will help you know what to expect and how to respond to any situation.
Phase Issues
Phase issues between microphones is something you will need to resolve first. A microphone captures a single sound wave.
When a second microphone picks up the same sound wave from a different location, the sound waves may be captured at slightly different times. Kind of like when two ripples in a pond expand outwards, but one starts at a peak while the other starts at a dip.
Sound waves are made up of frequencies. When two waves are not perfectly in sync, some frequencies will cancel out giving a thinner sound. This is known as partial cancellation.
In the worst possible case, the two sound waves line up exactly opposite each other and all frequencies are canceled out resulting in no sound at all.
Out of phase microphones can also cause comb filtering where some frequencies are boosted while others are cancelled. This can result in a boomy or hollow sound.
When the two waves are aligned (polarity is in sync), the sound is said to be in phase.
To eliminate phase issues, the first thing to try is to flip the polarity on one of the mic tracks in your DAW to see if that aligns the sound waves and fattens up the sound. If the sound is still thin, flip the polarity back to it’s original state and try moving one of the microphones around in small increments. Repositioning can sometimes help to align the sound waves being captured by the mics.
Close Mics
For rooms that, frankly, suck for recording drums, close mics are your friend. The overheads can provide the essential glue to bring the kit together (you certainly aren’t using them to capture the room), but you’ll be using the close mics to create the big sound you’re looking for. Before we talk about getting that big sound, we need to discuss how all of your close mics play with each other.
Phase, again
Please refer back to the section on phase issues. With individual drum mics so close to each other, you are most likely going to encounter phase issues. Unfortunately, there is no magic bullet to fix this. You’ll need to play around with the polarity and position of each mic until all of the drum tracks are as fat as they can be.
Let It Bleed , or not
When you mic a drum close up, you are able to take advantage of the unique sound of that drum. This allows you much more control over the sound of your overall kit. It is important to remember though, that the sound of other drums will probably end up bleeding through the mic as well. This is not necessarily a bad thing. Sometimes bleed provides the glue that brings all of the drums together. Producer Don Was was interviewed shortly after he and Keith Richards co-produced the Aaron Neville album My True Story. When asked how he got the amazing drum sounds on the record, he said that every drum was bleeding into the other which provided a big picture of what the drum kit sounded like as a whole in the room. If your goal however is to isolate each drum as much as possible, then here are a couple of suggestions to help.
Gating
Gating is the most widely used approach to isolating a drum. It is rare to be able to completely isolate a drum because of the close proximity of the drums to one another. To give it a go, insert the gate on the target drum channel, set the optimal input gain to get a strong signal into the gate, then find the point on the threshold where as much external sound as possible is eliminated. The goal is to have only the target drum’s signal passing through the gate. If you have frequency and filter controls available on the gate, then tweak them to lock in the optimal point where the gate is triggered. This may take some fiddling to get just right. Finally, work with the release knob so that the quietest sound from the gated drum is allowed to pass to the output before the release closes. This is sometimes very difficult to achieve since external sounds (for example, the tom right next door) are often louder than the quietest sound of the tom you are gating. This is why using a gate is almost always a compromise.
Compression
Another approach that many recordists have used successfully is to split the drum track that needs isolation into two tracks. Invert the polarity of one of the tracks. At this point, when you bring both up, they should completely cancel each other out. Now, insert a compressor on the inverted track. Set the ratio to the highest setting and the attack time very fast. Set the threshold so any external bleed is eliminated and only the drum passes through. Merge the split tracks back together on a subgroup. This now becomes your target drum’s new track. Play with the compressor until you achieve the best isolation. In effect, you are using the phase reversed compressor to cancel out frequencies that are not related to the target drum itself.
Once you have the individual drums under control, it’s time to lay down some kick ass drum tracks.
STOP! Please read the next paragraph carefully and commit it to memory.
Obviously, the most important task for the recordist is to record clear and concise tracks. By concise I mean a track that is crisp, well recorded, leveled perfectly and exactly what you and the client are looking for. Since the drums are being recorded in a less than stellar room, most inexperienced recordists will be tempted to immediately go for the EQs, compressors and reverbs to make each track sound huge and fat. There are two things wrong with this approach. First, you have to remember that the drum kit is a single instrument – the sum of it’s parts. The goal of recording individual drum tracks is to make each one shine in service to the kit itself. A bit of compression and EQ will certainly help each drum, but you should leave room shaping for the overall kit. This brings up thing #2. Don’t room shape when you are laying down tracks. Leave that for the mix. If you commit reverb and other effects to a track, you have effectively tied the hands of the mixer, whether that be you or someone else. You can’t possibly know exactly what the drum kit should sound like as a whole until you’ve brought up all the faders at mix time and have started to mix your sections. If you have a gorgeous room to record the drums then, yes, that becomes part of the permanent sound. But this article is about recording in less than perfect conditions. The good news is, without the benefit of that gorgeous room, you actually have more options at your disposal. You have the ability to add reverbs and delays to your drum kit subgroup to emulate a gorgeous room.
By not committing to a specific reverb or effect while recording the track, you can tweak the drum sound as you mix your other sections and nothing needs to be locked in until you are ready to bounce your mix.
In this article we covered overhead mics, close mics, mic placement, phase issues, isolation and keeping you drum tracks clean and basic to allow more flexibility at mix time. The Sound Sculptor will have more to say on recording drums and other instruments in a home recording studio environment. So
stay tuned!
By Jeff Neiblum