If you record acoustic guitar , then chances are you've either played around with stereo recording or at least thought about it. But maybe you're not sure which techniques to use and the pros and cons of each.
I think I can help.
I've recorded acoustic guitar more than any other instrument, so I've spent countless hours of quality time with my guitar and a pair of microphones. And I've gotten pretty good at getting great acoustic guitar tone.
What is stereo recording?
Stereo recording is simply using two microphones to capture a two-channel stereo” image of the source. By panning the signals left and right, you can create a sense of space and width and depth, simply by using two microphones instead of one.
Stereo mic techniques can be applied to any acoustic instrument - drum overheads, piano, cello, upright bass, choirs. I've used these same stereo techniques on all these instruments.
So even if you don't record acoustic guitar, keep reading. These techniques apply to all kinds of recording situations, and it's good to be familiar with them.
Mono recording (using only one microphone) is still very useful. There are plenty of times where I'll simply use one microphone on acoustic guitar, especially if it's for a bigger production where the guitar is playing a minor role. If the guitar is a big focus of the song, then I'll probably stereo-mic it.
Check out these two articles for more on stereo vs. mono recording:
1. XY
XY is oftentimes my go-to stereo technique. Why? Because it doesn't lend itself to phase issues. Phase issues can occur when multiple microphones pick up the same source. If the microphones are in different locations, then there's a chance they'll pick up the sound at different times.
Imagine taking two identical tracks in your DAW and delaying one by a few milliseconds. (Go try it if you've never done it.) What happens? Things start sounding thin. That's what happens when your two mics are out of phse.
With the XY technique, the mics are essentially at the same point in time, so any signal will hit both microphones at roughly the same time. It essentially gets rid of phase issues.
Pros - stereo image without any phase issues
Cons - not as wide” of an image as other techniques
2. ORTF
ORTF (it stands for some French phrase) is essentially taking the XY technique and flipping them outwards instead of inwards. The idea here is to create a recording that sounds very close to how the human ears hear.
The mics are approximately at the same distance and angle as our ears. On headphones, this technique sounds incredible. It's as if you're sitting in front of the guitar listening yourself. (For specific specs on ORTF, click here. )
Pros - realistic stereo field
3. Spaced Pair
Spaced pair is just like it sounds. You set up two microphones spaced out, facing the instrument. Spaced pair is the most susceptible to phase issues. I almost never get it right the first time. It requires a lot of attention and listening to get it right.
Spaced pair can give you a huge, wide sound, but only if you get the two mics in phase. The way I normally go about making sure they're in phase is to listen to the mics in mono. I'll pan both tracks to the center, and move the mics around until the mono signal sounds nice and full. If the sound is missing a lot of bass and sounds phasey, I know the mics aren't in phase yet.
Oftentimes just moving one mic a few inches will fix the problem. Once the mono signal sounds full and huge, you're ready. The stereo signal will be enormous. Be careful, though. If the guitarist moves or rotates a bit, you might be back out of phase again.
Pros - very wide sound
Cons - very susceptible to phase issues, center” isn't as clear
4. Over-the-Shoulder
Over-the-shoulder is a technique I've only used occasionally. Essentially you put a mono mic in front of the guitar and another mic over the neck pointing down. While this isn't a true” stereo technique, a lot of engineers use this as their default setup for recording acoustic guitar.
I find it to be a bit fickle. The front mic captures the body of the instrument, while the shoulder mic only captures the higher-end sound and pick noise. That means I can't really pan these very wide without it sounding funny.
It can give an interesting stereo image with lots of fret noise, if that's what the song needs.
Guitarists tend to like this technique because it sounds a lot like the guitar sounds to their ears when they're playing it.
Pros - if shoulder mic doesn't work, you can still use the front mic as a mono mic; grabs more finger/fret noise and air”
Cons - not really a L/R stereo technique, tends to capture a lot of pick noise, phase issues are still a concern
5. Mid-Side
Mid-side is the most complex technique, but it's pretty cool. The setup is one cardioid (or omni) microphone pointed at the guitar and another figure-8 microphone facing perpendicular to the first mic.
The mid mic gets recorded to its own track. The side mic gets recorded to TWO separate mono tracks (record the same signal to two tracks), panned left and right. Flip the phase on one of the tracks.
This allows you to adjust the width of the recording. The more you bring up the side tracks, the wider the sound. The more you bring up the mid mic, the more mono” the sound.
What's great about this is you can change the width after-the-fact. If you're mixing and wish the track was wider, you can make it happen. You can't do that with any other technique.
Like the XY technique, mid-side doesn't tend to have many phase issues, because the mic capsules are so close together. If your room is noisy or not very well treated acoustically, then this technique might not be for you, as the sid mic is picking up everything to the left and right of the guitar (your room).
Pros - very little phase issues, mono-compatible, adjustable width
Cons - more complex/confusing to set up, having too many choices may bog you down later, harder to ‘commit' to a sound
Showing posts with label stereo. Show all posts
Showing posts with label stereo. Show all posts
Wednesday, 21 December 2016
Tuesday, 18 October 2016
Five Techniques For Stereo Miking Drums
By Matt McGlynn
A single pair of multipattern condenser microphones can provide at least five distinct overhead drum miking choices with surprisingly different sonic characteristics.
To demonstrate these different sounds, we recorded a drum kit with a pair of KSM44A overhead microphones five different ways. The drums, the room, the preamps, cables, and composition remained the same. The only variable was the position of the microphones (and in one case, the polar pattern).
How different can a single pair of microphones, in the same room with the same drums, really sound? As you listen to the tracks below, consider the following:
Width of stereo field
Ease of setup
The XY or coincident pair approach wins points for its guaranteed mono compatibility. Because the two capsules are so close together (coincident”), sound waves from every drum and cymbal impinge upon the two mics' diaphragms nearly simultaneously, avoiding any risk of comb-filtering due to partial cancellation of out-of-phase waves when the two OH tracks are heard in mono.
A consequence of coincident positioning is that the resulting stereo field is narrow, even when the two OH tracks are panned hard L/R. This is a good choice for arrangements in which the drums play a supporting role, or when mono compatibility is critical.
Overhead microphone height is an important consideration in this and every technique. If the mics are very high, the capsules will point straight over the sides of the of the kit, essentially putting the entire instrument off-axis. This will result in an overly roomy sound.
Lowering the microphones, or using an angle less than 90o can result in a more direct sound, although the kick and snare will always be off-axis.
Regardless of height, I recommend mounting the XY array directly above the snare drum, to ensure that the snare is centered in the stereo image.
The M-S technique, like XY, ensures mono compatibility. And like XY, it produces a relatively narrow stereo spread.
A primary benefit is that the perceived size of the space can be changed at mix time, by varying the amount of side” channel in the mix. This is often described as adjusting the stereo width,” but to my ear the drum kit doesn't get any wider. The high and low toms don't get farther apart. The room gets bigger, but the drums sound less direct.
The challenge of M-S is that one of the two microphones is not pointed at the drum kit. The figure-of-8 mic is positioned so the drums are in the mic's null point; the microphone hears only reflected sound. If you are recording drums in a small or untreated room, chances are this reflected sound is not what you want on your record.
But if the room does sound good, M-S is a great way to combine a dry, direct sound — the Mid mic — with as much room ambience as suits the rest of the production.
The Recorderman technique is probably the newest and least-known technique here, although it is conceptually similar to the overhead configuration of Glyn Johns' more-famous approach.
It requires two Cardioid microphones. One is suspended 32” above the center of the snare drum, pointing straight down. The other is positioned near the drummer's right shoulder, pointing directly at the snare drum from 32″ away.
This technique requires that the kick drum is also equidistant from both microphones. This can be checked by taping the two ends of a length of string to the center of the snare and kick drums, respectively. Pinch the string together at the point where it touches the mic above the snare, so that both legs of the string are taut. Move that point of the string in an arc toward the drummer's right shoulder to find the perfect location of the second microphone — at a point where it, too, is 32” from the center of the snare, and equally distant from the kick as is the first microphone.
The two tracks are panned L and R, although not necessarily 100%. Extreme panning of Recorderman overhead tracks can leave a hole in the middle of the stereo field.
Mono compatibility is not guaranteed, except for the kick and snare.
Because the microphones are relatively low, they will hear primarily the drums themselves. Cymbals will be understated, as will the sound of the room.
This is therefore a great way to combat some of the problems that plague live drum recording in home or project studios:
Small, untreated rooms that don't sound great
Untrained drummers who bash their cymbals
Even in large, purpose-built studios, the Recorderman technique is a useful way to capture dry overhead tracks that can be supplemented with more-distant ambient microphones, should the arrangement call for a roomier sound.
With a stereo bar, ORTF becomes very easy to use. Once the two microphones are locked into position — with capsules 17cm apart, at 110o- the single stand can easily be raised, lowered, or angled to tune the array to best suit the size of the kit, the sound of the room, and the desired amount of ambience in the recorded track.
Due to the wide spread of the microphones, it is likely that most of the drum kit will be between them, off-axis. This approach, like mid-side, is less likely to succeed in a small or untreated space, because the microphones will mostly hear reflected sounds. Moving the array closer to the drum kit, whether from behind or over the top, will result in a drier sound.
The ORTF stereo image is wider than XY, MS, or Recorderman, but not unbelievably so. Perhaps because the microphone position simulates human ear position, the resulting stereo field seems very natural and realistic, and generally collapses to mono without significant problems.
AB/Spaced Pair
The AB or Spaced Pair approach is among the simplest stereo techniques to understand, but it presents the most problems in practice.
Because the microphones are far apart, AB arrays are susceptible to comb filtering. The risk can be mitigated somewhat by keeping the two microphone capsules equidistant from the center of the snare drum — but even then, the mic placement should be auditioned (in mono) to reveal possible problems with the kick, toms, or cymbals.
Aside from phase-coherency challenges, AB is a powerful technique, with a large palette of sonic colors. By lowering the array, or angling the microphones in toward the center of the kit, room sound can be minimized. Conversely, there are numerous ways to use an AB pair to capture a roomier, indirect sound: by raising the microphones, moving them further out toward the sides of the kit, angling them to point straight down, or changing from Cardioid to a wider polar pattern.
AB arrays can produce a wide stereo image, simply because drums or cymbals very near one of the two microphones will be perceived to come from only that side of the stereo field.
This can result in an unrealistically large-sounding drum kit, if the overhead tracks are panned 100% L/R.
Head to head Comparison
Drum Miking Cheat Sheet
To minimize room sound, lower the OH microphones and point them toward the center of the kit.
To maximize room sound, raise the OH microphones, angle them away from the drums, or use wider polar patterns.
To minimize cymbal sound, try Recorderman.
To ensure mono compatibility, use XY or MS.
For the widest possible stereo spread, use AB.
Avoid phase coherency problems with kick and snare by keeping them centered between the OH mics.
Dry overhead tracks can be optionally supplemented with room mics.
A pair of cardioid mics provides several distinct, viable OH sounds.
Multipattern LDCs provide even more options.
A single pair of multipattern condenser microphones can provide at least five distinct overhead drum miking choices with surprisingly different sonic characteristics.
To demonstrate these different sounds, we recorded a drum kit with a pair of KSM44A overhead microphones five different ways. The drums, the room, the preamps, cables, and composition remained the same. The only variable was the position of the microphones (and in one case, the polar pattern).
How different can a single pair of microphones, in the same room with the same drums, really sound? As you listen to the tracks below, consider the following:
Width of stereo field
Ease of setup
The XY or coincident pair approach wins points for its guaranteed mono compatibility. Because the two capsules are so close together (coincident”), sound waves from every drum and cymbal impinge upon the two mics' diaphragms nearly simultaneously, avoiding any risk of comb-filtering due to partial cancellation of out-of-phase waves when the two OH tracks are heard in mono.
A consequence of coincident positioning is that the resulting stereo field is narrow, even when the two OH tracks are panned hard L/R. This is a good choice for arrangements in which the drums play a supporting role, or when mono compatibility is critical.
Overhead microphone height is an important consideration in this and every technique. If the mics are very high, the capsules will point straight over the sides of the of the kit, essentially putting the entire instrument off-axis. This will result in an overly roomy sound.
Lowering the microphones, or using an angle less than 90o can result in a more direct sound, although the kick and snare will always be off-axis.
Regardless of height, I recommend mounting the XY array directly above the snare drum, to ensure that the snare is centered in the stereo image.
The M-S technique, like XY, ensures mono compatibility. And like XY, it produces a relatively narrow stereo spread.
A primary benefit is that the perceived size of the space can be changed at mix time, by varying the amount of side” channel in the mix. This is often described as adjusting the stereo width,” but to my ear the drum kit doesn't get any wider. The high and low toms don't get farther apart. The room gets bigger, but the drums sound less direct.
The challenge of M-S is that one of the two microphones is not pointed at the drum kit. The figure-of-8 mic is positioned so the drums are in the mic's null point; the microphone hears only reflected sound. If you are recording drums in a small or untreated room, chances are this reflected sound is not what you want on your record.
But if the room does sound good, M-S is a great way to combine a dry, direct sound — the Mid mic — with as much room ambience as suits the rest of the production.
The Recorderman technique is probably the newest and least-known technique here, although it is conceptually similar to the overhead configuration of Glyn Johns' more-famous approach.
It requires two Cardioid microphones. One is suspended 32” above the center of the snare drum, pointing straight down. The other is positioned near the drummer's right shoulder, pointing directly at the snare drum from 32″ away.
This technique requires that the kick drum is also equidistant from both microphones. This can be checked by taping the two ends of a length of string to the center of the snare and kick drums, respectively. Pinch the string together at the point where it touches the mic above the snare, so that both legs of the string are taut. Move that point of the string in an arc toward the drummer's right shoulder to find the perfect location of the second microphone — at a point where it, too, is 32” from the center of the snare, and equally distant from the kick as is the first microphone.
The two tracks are panned L and R, although not necessarily 100%. Extreme panning of Recorderman overhead tracks can leave a hole in the middle of the stereo field.
Mono compatibility is not guaranteed, except for the kick and snare.
Because the microphones are relatively low, they will hear primarily the drums themselves. Cymbals will be understated, as will the sound of the room.
This is therefore a great way to combat some of the problems that plague live drum recording in home or project studios:
Small, untreated rooms that don't sound great
Untrained drummers who bash their cymbals
Even in large, purpose-built studios, the Recorderman technique is a useful way to capture dry overhead tracks that can be supplemented with more-distant ambient microphones, should the arrangement call for a roomier sound.
With a stereo bar, ORTF becomes very easy to use. Once the two microphones are locked into position — with capsules 17cm apart, at 110o- the single stand can easily be raised, lowered, or angled to tune the array to best suit the size of the kit, the sound of the room, and the desired amount of ambience in the recorded track.
Due to the wide spread of the microphones, it is likely that most of the drum kit will be between them, off-axis. This approach, like mid-side, is less likely to succeed in a small or untreated space, because the microphones will mostly hear reflected sounds. Moving the array closer to the drum kit, whether from behind or over the top, will result in a drier sound.
The ORTF stereo image is wider than XY, MS, or Recorderman, but not unbelievably so. Perhaps because the microphone position simulates human ear position, the resulting stereo field seems very natural and realistic, and generally collapses to mono without significant problems.
AB/Spaced Pair
The AB or Spaced Pair approach is among the simplest stereo techniques to understand, but it presents the most problems in practice.
Because the microphones are far apart, AB arrays are susceptible to comb filtering. The risk can be mitigated somewhat by keeping the two microphone capsules equidistant from the center of the snare drum — but even then, the mic placement should be auditioned (in mono) to reveal possible problems with the kick, toms, or cymbals.
Aside from phase-coherency challenges, AB is a powerful technique, with a large palette of sonic colors. By lowering the array, or angling the microphones in toward the center of the kit, room sound can be minimized. Conversely, there are numerous ways to use an AB pair to capture a roomier, indirect sound: by raising the microphones, moving them further out toward the sides of the kit, angling them to point straight down, or changing from Cardioid to a wider polar pattern.
AB arrays can produce a wide stereo image, simply because drums or cymbals very near one of the two microphones will be perceived to come from only that side of the stereo field.
This can result in an unrealistically large-sounding drum kit, if the overhead tracks are panned 100% L/R.
Head to head Comparison
Drum Miking Cheat Sheet
To minimize room sound, lower the OH microphones and point them toward the center of the kit.
To maximize room sound, raise the OH microphones, angle them away from the drums, or use wider polar patterns.
To minimize cymbal sound, try Recorderman.
To ensure mono compatibility, use XY or MS.
For the widest possible stereo spread, use AB.
Avoid phase coherency problems with kick and snare by keeping them centered between the OH mics.
Dry overhead tracks can be optionally supplemented with room mics.
A pair of cardioid mics provides several distinct, viable OH sounds.
Multipattern LDCs provide even more options.
Thursday, 28 July 2016
6 Stereo Miking Techniques You Can Use Today
Twice a month we revisit some of our reader favorite posts from throughout the history of Audiotuts+. This tutorial was first published in August 2008.
Stereo miking is a great way to increase the sense of depth in your recording of an instrument. Here are six stereo miking techniques you can try out today. We'll start with the basics and then move to some more exciting options.
Before You Get Started
One thing to be careful of in stereo recording is phase cancellation. When using a spaced pair this can be a concern. Phase cancellation occurs when two versions of the same sound, which occur at slightly different times, are mixed together. The result is that when one signal is going into positive amplitude and the other is going into negative amplitude they will cancel each other out and when they are both going the same way they will boost each other.
When two signals are out of phase you will notice a warble in your sound or, if the two signals are 180 degrees out of phase, you will get silence. You will not notice this when the two signals are panned hard left and right. So, to avoid any surprises always check in mono.
The way to minimize your chance of running into phase problems is to use coincident pairs (where the two mics are very close together) or to use the 3:1 rule (place the mics 3 times as far from each other as they are from the sound source).
Spaced Pair
Spaced pair miking is exactly what the name implies. Two cardioid microphones are placed apart from each other to produce two different recordings of the same instrument. I suggest trying two places on the instrument that produce different tonalities. For example, on a guitar you may want to have one mic on the bridge and one on the nut.
X-Y
The X-Y configuration takes two cardioid microphones and places them with heads together at 90 degree angles. The result is that the mic on the left will pickup the right side of the room and the mic on the right will pickup the left side of the room.
Blumlein Pair
The Blumlein Pair is much like the X-Y technique with one variation. Two bi-directional mics are used at 90 degree angles. The result of this technique is that one mic will pickup the front left and back right of the room while the other picks up the front right and back left of the room. This technique is best if you have a nice sounding room to record in.
ORTF
The ORTF technique is named after the French television and radio commission who invented it (Office de Radiodiffusion-Télévision Française). This is a binaural mic technique which means it is meant to approximate the response of your two ears. In the ORTF technique two cardioid mics are placed at an angle of 110 degrees with the heads 17cm (7”) apart. The beauty of this technique is that mic placement can be as simple as moving around the room until it sounds good and then placing the mics where your head was.
Mid-side
In this technique a cardioid mic is placed facing the sound source and a bi-directional mic is placed perpendicular to the cardioid mic (so it is picking up the sides of the room). They are each recorded onto one track. The track with the bidirectional microphone is then copied and the phase is inverted on the copy. The two bi-directional tracks are then panned hard left and right while the cardioid mic is panned center. By adjusting the relative volume of the cardioid mic we can control how close or far away the recorded instrument sounds.
Note: This technique only works in stereo. If this is played back in mono the two bi-directional tracks will cancel each other out.
Decca Tree
The Decca Tree is used mainly for recording orchestras and large ensembles. It was developed in the 1950s by engineers at Decca Records. The Decca Tree uses a special T-shaped mic stand suspended above the conductor's head. On the T-shaped stand are 3 cardioid microphones facing left, right and centre which are then panned to match their configuration.
There are no fixed measurements for the distance between the microphones but the standard seems to be around 5-7 feet. The mics are usually placed closer together for smaller orchestras and further apart for larger ones.
Stereo miking is a great way to increase the sense of depth in your recording of an instrument. Here are six stereo miking techniques you can try out today. We'll start with the basics and then move to some more exciting options.
Before You Get Started
One thing to be careful of in stereo recording is phase cancellation. When using a spaced pair this can be a concern. Phase cancellation occurs when two versions of the same sound, which occur at slightly different times, are mixed together. The result is that when one signal is going into positive amplitude and the other is going into negative amplitude they will cancel each other out and when they are both going the same way they will boost each other.
When two signals are out of phase you will notice a warble in your sound or, if the two signals are 180 degrees out of phase, you will get silence. You will not notice this when the two signals are panned hard left and right. So, to avoid any surprises always check in mono.
The way to minimize your chance of running into phase problems is to use coincident pairs (where the two mics are very close together) or to use the 3:1 rule (place the mics 3 times as far from each other as they are from the sound source).
Spaced Pair
Spaced pair miking is exactly what the name implies. Two cardioid microphones are placed apart from each other to produce two different recordings of the same instrument. I suggest trying two places on the instrument that produce different tonalities. For example, on a guitar you may want to have one mic on the bridge and one on the nut.
X-Y
The X-Y configuration takes two cardioid microphones and places them with heads together at 90 degree angles. The result is that the mic on the left will pickup the right side of the room and the mic on the right will pickup the left side of the room.
Blumlein Pair
The Blumlein Pair is much like the X-Y technique with one variation. Two bi-directional mics are used at 90 degree angles. The result of this technique is that one mic will pickup the front left and back right of the room while the other picks up the front right and back left of the room. This technique is best if you have a nice sounding room to record in.
ORTF
The ORTF technique is named after the French television and radio commission who invented it (Office de Radiodiffusion-Télévision Française). This is a binaural mic technique which means it is meant to approximate the response of your two ears. In the ORTF technique two cardioid mics are placed at an angle of 110 degrees with the heads 17cm (7”) apart. The beauty of this technique is that mic placement can be as simple as moving around the room until it sounds good and then placing the mics where your head was.
Mid-side
In this technique a cardioid mic is placed facing the sound source and a bi-directional mic is placed perpendicular to the cardioid mic (so it is picking up the sides of the room). They are each recorded onto one track. The track with the bidirectional microphone is then copied and the phase is inverted on the copy. The two bi-directional tracks are then panned hard left and right while the cardioid mic is panned center. By adjusting the relative volume of the cardioid mic we can control how close or far away the recorded instrument sounds.
Note: This technique only works in stereo. If this is played back in mono the two bi-directional tracks will cancel each other out.
Decca Tree
The Decca Tree is used mainly for recording orchestras and large ensembles. It was developed in the 1950s by engineers at Decca Records. The Decca Tree uses a special T-shaped mic stand suspended above the conductor's head. On the T-shaped stand are 3 cardioid microphones facing left, right and centre which are then panned to match their configuration.
There are no fixed measurements for the distance between the microphones but the standard seems to be around 5-7 feet. The mics are usually placed closer together for smaller orchestras and further apart for larger ones.
Thursday, 14 July 2016
Stereo Miking Techniques For Recording Acoustic Guitar
The Three Techniques
All three of the following techniques have been used on countless hit records. You should familiarize yourself with all of them and then experiment with each to achieve your desired tone. In most situations, you'll want to use a pair of unidirectional, condenser mics placed close to the instrument (approximately 6 to 12 inches away). Mics with a cardioid polar pattern are generally best for an acoustic guitar because they exhibit less "bass-boost" from proximity effect than other directional types when placed close to the sound source.
Acoustic guitars will exhibit a "boomy" sound if miked incorrectly. Experiment with different mic combinations to achieve the sound you're after.
Spaced Mics - Setup 1
For this setup, two mics are spaced apart from each other at the same approximate height. My preference for the first mic is a small diaphragm condenser mic pointed at the 12th fret of the guitar to capture higher frequencies and string dynamics. For the second mic, I use a large diaphragm condenser aimed at the bridge or slightly behind it, to capture the lower frequencies and body characteristics of the acoustic guitar. When using this technique, remember to follow the Rule of 3:1,” where the distance between the two mics is at least three times the distance between each mic and the acoustic guitar. (For example, if Mic A is 6” from the twelfth fret, Mic B should be at least 18” away from Mic A.) This will help keep phase cancellations to a minimum and provide a smoother sound that will translate well to mono should you decide to do that later.
Spaced Mics - Setup 2
This technique is primarily a variation on the previous spaced mics setup. The first mic is still a small diaphragm condenser pointed at the twelfth fret. The second mic, however, is positioned on a mic stand around the performer's ear level, pointing down either at the bridge or at the strings just in front of the bridge. For a right-handed player, the mic will be positioned over the right shoulder. It should be placed out in front of the guitar and the performer and angled back towards the guitar (as opposed to pointing at the ground). This setup will yield a brighter sound that is thinner, but more open sounding than the first setup. Keep the Rule of 3:1” in mind, but experiment with the mic placement slightly to improve the timbre.
X-Y Stereo Mics
X-Y, also known as a coincident pair, is probably the easiest and most reliable method for recording acoustic guitar. It is hard to get a bad or unnatural-sounding recording with this setup for several reasons. First, the mics are positioned similarly to how our own ears hear an acoustic guitar. Second, you do not need to be as concerned with the phase issues apparent in the other setups because the capsules are so close to each other. Last, because the sound waves arrive at roughly the same time to both mics, and phase issues are minimized, the resulting tracks will be highly mono-compatible, if so desired. To start, place two small diaphragm condenser mics (a matched pair is ideal) so that one capsule is above the other (nearly touching) and the back ends are split apart roughly 90 to 120 degrees, forming a V-shape. Keep the capsules focused on the 12th fret, but feel free to move the mics further away to capture more of the room, or slightly left or right of the 12th fret to emphasize particular frequencies. I find that about 7 inches back from the 12th fret often yields the sweet spot between the bass frequencies from the sound hole and higher frequencies from the neck, and in effect de-emphasizes the midrange frequencies. This setup will create a narrower stereo image than the other two setups discussed, but will make up for it with a warmer, more natural sound.
EQ, Compression
While some engineers like to add compression and EQ to acoustic guitars when recording, others prefer to add those touches after the fact and only as needed. It's hard to know just how an acoustic guitar track will sit in a mix, and hey, that's what all of these wonderful UAD Powered Plug-Ins are for anyway! In the end, and once again, there are no rules. So, have fun experimenting with these stereo pair recording techniques for acoustic guitar and stay tuned for more tips next month with Studio Basics.
All three of the following techniques have been used on countless hit records. You should familiarize yourself with all of them and then experiment with each to achieve your desired tone. In most situations, you'll want to use a pair of unidirectional, condenser mics placed close to the instrument (approximately 6 to 12 inches away). Mics with a cardioid polar pattern are generally best for an acoustic guitar because they exhibit less "bass-boost" from proximity effect than other directional types when placed close to the sound source.
Acoustic guitars will exhibit a "boomy" sound if miked incorrectly. Experiment with different mic combinations to achieve the sound you're after.
Spaced Mics - Setup 1
For this setup, two mics are spaced apart from each other at the same approximate height. My preference for the first mic is a small diaphragm condenser mic pointed at the 12th fret of the guitar to capture higher frequencies and string dynamics. For the second mic, I use a large diaphragm condenser aimed at the bridge or slightly behind it, to capture the lower frequencies and body characteristics of the acoustic guitar. When using this technique, remember to follow the Rule of 3:1,” where the distance between the two mics is at least three times the distance between each mic and the acoustic guitar. (For example, if Mic A is 6” from the twelfth fret, Mic B should be at least 18” away from Mic A.) This will help keep phase cancellations to a minimum and provide a smoother sound that will translate well to mono should you decide to do that later.
Spaced Mics - Setup 2
This technique is primarily a variation on the previous spaced mics setup. The first mic is still a small diaphragm condenser pointed at the twelfth fret. The second mic, however, is positioned on a mic stand around the performer's ear level, pointing down either at the bridge or at the strings just in front of the bridge. For a right-handed player, the mic will be positioned over the right shoulder. It should be placed out in front of the guitar and the performer and angled back towards the guitar (as opposed to pointing at the ground). This setup will yield a brighter sound that is thinner, but more open sounding than the first setup. Keep the Rule of 3:1” in mind, but experiment with the mic placement slightly to improve the timbre.
X-Y Stereo Mics
X-Y, also known as a coincident pair, is probably the easiest and most reliable method for recording acoustic guitar. It is hard to get a bad or unnatural-sounding recording with this setup for several reasons. First, the mics are positioned similarly to how our own ears hear an acoustic guitar. Second, you do not need to be as concerned with the phase issues apparent in the other setups because the capsules are so close to each other. Last, because the sound waves arrive at roughly the same time to both mics, and phase issues are minimized, the resulting tracks will be highly mono-compatible, if so desired. To start, place two small diaphragm condenser mics (a matched pair is ideal) so that one capsule is above the other (nearly touching) and the back ends are split apart roughly 90 to 120 degrees, forming a V-shape. Keep the capsules focused on the 12th fret, but feel free to move the mics further away to capture more of the room, or slightly left or right of the 12th fret to emphasize particular frequencies. I find that about 7 inches back from the 12th fret often yields the sweet spot between the bass frequencies from the sound hole and higher frequencies from the neck, and in effect de-emphasizes the midrange frequencies. This setup will create a narrower stereo image than the other two setups discussed, but will make up for it with a warmer, more natural sound.
EQ, Compression
While some engineers like to add compression and EQ to acoustic guitars when recording, others prefer to add those touches after the fact and only as needed. It's hard to know just how an acoustic guitar track will sit in a mix, and hey, that's what all of these wonderful UAD Powered Plug-Ins are for anyway! In the end, and once again, there are no rules. So, have fun experimenting with these stereo pair recording techniques for acoustic guitar and stay tuned for more tips next month with Studio Basics.
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