Best Live Sound Mic Placement Techniques

Date:2020/2/18 21:06:52 Hits:

Getting great live sound is as much an art as it is a science, and much of that has to do with basic engineering techniques. Mic placement is one of the biggest factors of good live sound — nothing you do at the board can fix poor mic placement. While experience is the best teacher, especially when it comes to the constantly changing variables of sound reinforcement, here are some guidelines that can save you a lot of time sorting it out on your own.

General Tips
In a live setting, the biggest challenge most engineers face is getting the most gain without feedback, and the noise onstage and from the venue’s mechanical systems typically masks finer details like the noise floor of the mics.

The noise-masking acoustic diffusion you get in the best live venues lets you get away with all kinds of tricks, from extreme EQing to dynamics processing that would sound awful on a studio album. Modern feedback-suppression processing, such as the type you get with a dbx DriveRack PA2, can also work wonders, providing you with extra mic-placement flexibility. However, you’ll be courting disaster if you rely on this technology to make up for poor mic placement.

Low-sensitivity dynamic microphones are the most popular choice when it comes to miking live instruments, and although there are many alternatives, the Shure SM57 is still the king of the jungle. That said, condenser microphones have made serious inroads into sound reinforcement, and many engineers enjoy their ability to pick up high-frequency details.

No matter what kind of microphone you choose for any given task, you’ll generally want to stick with ones that have standard cardioid patterns. Their off-axis sound rejection protects against sound from stage monitors or the main PA that can cause feedback. While tempting, supercardioid and hypercardioid mics actually pick up a significant amount of sound from the rear, making them a bit trickier to use onstage.

The most important element of live microphone placement is the distance from the microphone to the source. In most cases, you’ll want to get the mic as close to the sound source as possible, which increases the ratio of direct sound to background noise. The greater the gap between direct sound and background noise, the higher you can crank up the gain at the board, without risking feedback.

One final broad-stroke concept about microphone placement in general, which is just as applicable to studio recording as it is to sound reinforcement, is the idea of finding the sweet spot. Every sound source, from guitar cabinets to kick drums, has a spot or two where all the complexities of acoustics and harmonics come together to provide you with the most desirable sound.

Finding that sweet spot can be a matter of moving a mic an inch to the left or right or just backing it up or moving it a bit closer. Still, it makes a huge difference, and having the patience to find the sweet spot is one of the defining traits of a professional sound engineer. You can speed things along by having an assistant move your mics while you listen in the house. Also, if you’re going to mic up the same instruments for multiple shows, save yourself a lot of time by marking the sweet spots with colored tape.

Vocals
Vocal mic positioning is often about as easy as it gets. As long as you’ve picked the right mic, you’re in good shape. Where it gets tricky is that actual mic positioning isn’t up to you, it’s up to the singer, especially those who hold the mic in their hand. This is where having a good chat with the lead vocalist before the sound check can be a real lifesaver.

In fact, one of the most annoying problems you’ll come across is that vocalists tend to hold back as you dial in the PA. That’s usually because they either haven’t warmed up or are saving their voices for the show. Either way, it’s important to convince them to provide you with realistic levels so you don’t crank the gain and regret it when the show starts and they finally start singing out.

Probably the most frustrating thing about miking vocals is that you have no way to manage the distance between the vocalist’s mouth and the microphone. When singers either step back too far or don’t sing directly into the mic, that critical ratio of direct sound to background noise decreases dangerously, and feedback becomes almost inevitable. On the other hand, you have to deal with the proximity effect when the vocalist is too close. When a vocalist eats the mic, they produce a large low-frequency boost. It may sound cool on its own, but it will absolutely muddy the live mix, rendering the vocals unintelligible unless you drastically roll off the low end.

Chances are, you can’t fix a singer’s bad habits. But you can always suggest that the particular microphone you’ve set up will work best if the singer projects directly into it and doesn’t choke up on the grille. This little trick just may get you the clean, proximity-effect-free, on-axis sound you want.

Once the singer picks up the mic, things can get a little hairy. The biggest culprits are cupping the mic and creeping in front of the PA speakers. The best time to catch mic cupping is during the sound check. Simply explaining that cutting off the phase ports will likely cause feedback is usually enough. If there’s any chance the singer could stray in front of the speakers, you probably want to point or even mark out the do-not-cross line with colored tape.

Of course, there are many other circumstances that make live vocal miking a complex subject. Headset microphones, for instance, come with their own set of challenges. You can read more about frequent vocal mic mistakes that are ruining your vocals and how to catch or avoid them.

Electric Guitars
The most effective ways to mic electric guitar cabinets onstage are virtually identical to common mic techniques used in studio production. The biggest difference is that you’re less likely to use condensers live, and you can usually get away with just a single cardioid dynamic mic. In addition to the Shure SM57, Sennheiser’s e609 Silver is a popular alternative, both because it sounds great and because you can simply drape it over cabinets, without bothering with a stand.

Modern durable ribbon microphones, such as the Royer R-121 Live, are drastically different from standard dynamic mics, both sonically and functionally. You can stick one right up to the grille and get amazingly accurate sound. The off-axis rejection of the figure-8 polar pattern can also work miracles live. Learn more about using ribbons live.

Common practice for large venues is to use two mics — one for midrange and one for low end. For smaller venues, you can ditch the low-end mic. You’ll get plenty of low end from the amp, but the mids and upper mids tend to get sucked out by the acoustics of the venue, leaving the amp tone onstage too weak to cut through the mix. You’ll typically pick up these frequencies near the center or slightly off-center of the speaker cone. Here’s a great video by Mitch Gallagher and Don Carr demonstrating how to find the sweet spot on any guitar amplifier.

Royer R-122 on Keith Urban's guitar rig. Note the positioning tape on the grille. Photo courtesy of Royer.
Royer R-122 on Keith Urban’s guitar rig. Note the positioning tape on the grille. Photo courtesy of Royer.

Here are a couple of bonus tips for miking guitar cabs live. First, if it’s an option, then you really want to get guitar amps up off the ground, especially if they’re on a hollow stage. This will cut down on low-frequency buildup, reducing overall stage volume and forcing you to do a lot less work balancing out excessive bass in the house. Second, if you’re going to mic the same amp for several shows, then mark the sweet spot or spots with a bit of tape. It won’t affect the amp, no one will see it from the audience, and it will save you a lot of setup time.

Anyone who’s miked up an acoustic guitar in the studio knows that getting great sound from an average acoustic guitar can be a challenge, and it’s even harder to do it live. Even the most accommodating live microphones, such as DPA’s d:vote VO4099-G, can turn into feedback monsters under the right conditions, and in the constantly shifting acoustics of live venues, it’s almost impossible to guess when that will be.

If you have to use a microphone on an acoustic guitar live, there are three things you can do to get the best results with the lowest chance of feedback. First, stick with a low-sensitivity cardioid mic and aim it either at the bridge or at the neck joint. Second, get it as close to the guitar as possible. This will get the most direct sound, so you can back off on the gain, and it has the secondary effect of keeping the performer from moving the guitar too much.

You may still want to suggest to the performer not to swing the soundhole at the mic, but that’s going to be your biggest wild card, no matter what. That brings us to number three: plug up that soundhole. Planet Waves’ Screeching Halt Acoustic Guitar Feedback Eliminator is a favorite around Sweetwater.

Want a better way to get great acoustic guitar sound live? Don’t use a mic. Many professional live sound engineers invest in an easy-to-install soundhole pickup, such as a Seymour Duncan Woody. You can install a low-profile drop-in pickup like this in minutes, if not seconds. Not only will it completely eliminate the need to mic the guitar, but it may also solve a number of other acoustic sound issues you’re likely to run into live.

Drums
By far, the biggest mic-placement challenge most live sound engineers face is choosing and placing the right drum mics. The tricky thing about drum mic placement for sound reinforcement is figuring out exactly what you need to mic up. If you’re in a small space, then there’s a good chance you won’t need to mic up the kit at all. In fact, you may need to isolate the drums with something like ClearSonic acrylic acoustic isolation panels, or the rest of the band will have to dial it up to contend with the drums, and you’ll blow your audience away.

Another thing you don’t have to deal with in the studio is the aesthetic side of drum miking. No one wants to see a cage of microphone stands and booms surrounding the drummer. Unless you invest in high-end options like Triad-Orbit mic stands, you’ll need to get creative about mic positioning. Mounts that clamp onto drum rims, such as the On-Stage Stands DM50 Drum Rim Mic Clip, can be a good alternative to traditional stands.

Kick Drum
Sweetwater’s in-house master recording engineer Mark Hornsby and seasoned pro drummer Nick D’Virgilio created an excellent video on how to mic a kick drum, and almost all of it is useful for live sound. One of the essential tips they mention is using special high-density pillows such as these dense DW Pro-Cushion Pillows to deaden resonance. While they will fatten up your kick, these pillows also help reduce the chance of feedback, allowing you to push the gain if you need to.

When it comes to mic placement, it’s going to depend a lot on the sound of the kick itself. As opposed to studio recording, reinforcing kick drums live is all about getting the most punch you can. Unless you’re miking up drums in a high-end venue with meticulously balanced acoustics (in which case, stick to studio techniques), your biggest goal is to balance the natural low-frequency buildup you get from most live sound venues with midrange attack.

You probably won’t get the results you want from the standard “stick a ’57 at the port” technique favored by amateur sound guys everywhere. What you want to do instead is to get inside the kick. Option one is to use a small boom to position a mic an inch or two off the beater. This will capture the click of the attack and midrange detail that normally gets buried in the bass. It might sound strange if you solo it, but the added harmonics and attack make the bass punchier, the same way adding salt to caramel brings out the sweetness.

Option two is to place a boundary mic inside the kick. The best place for it is on a dampening cushion near the beater head. This will allow you to capture more of the shell resonance, while balancing out the lows with beater attack. It’s a great choice for midsized venues, since you get a fuller sound than with a small mic at the beater.

If you’re working with a kick drum that doesn’t have a port in the resonant head, then your best bet in a smaller venue is to stick that dynamic mic off the center of the resonant head. You won’t get quite as much attack, but you can balance the mid and low frequencies by moving the mic between the middle and edge of the head to find the sweet spot.

In cases where you are coming up short on beefy bass or you actually need to mic up the whole kit for a large venue, placing a large-diaphragm microphone just inside the port will give you tons of bottom end. You’ll absolutely want to supplement this with a mic inside the kick, since you’ll need to balance the tone at the board.

Snare and Toms
A basic approach to miking snares and toms is to think of the mic (almost always a front-address dynamic) as a flashlight. You want to shine the beam across the surface of the drum, starting about an inch in from the rim and across to the other side of the head. You’ll typically get the best results by positioning the mic somewhere between one and two inches off the head.

Snare drums in particular benefit from rim mounts, since they keep the mic at a consistent distance from the head (snare drums tend to move a bit throughout the show) and extremely stable. Drum mics such as the popular Sennheiser e604 not only come with clips, but their low-profile design lets them stay safely out of the way of swinging sticks.

You start adding mics around the kit as the size of the venue grows, and around the time you start sticking mics on toms, you may want to consider tossing a microphone under the snare drum. This will allow you to mix extra snare snap in with the more resonant sound you get from above. As for toms — when you need to mic them, you’ll find the same technique you used on the top-side snare mic (and often even the mic itself) will do the trick.

There’s a good chance you won’t have to mic toms at all, because there isn’t a big gap between the point where you want to mic toms and the point where you need to mic cymbals. Often, you’ll get more than enough toms in the overheads so that deliberately miking them is pointless. To that effect, your overhead microphones really aren’t there just to capture cymbals; rather, they take in the kit as a whole.

The most common practice for setting up drum overheads is to approach the kit from the sides and aim a split pair of large-diaphragm condensers down. Rather than attempt to calculate the distance above the kit or from the other overhead, keep the flashlight analogy going and try to make sure you’re covering the whole drum kit, without angling the mics too much.

By the way, here’s another place where using a figure-8 polar pattern can be extremely useful, since you can use that extreme side rejection to effectively isolate the kit from the rest of the band. Multi-pattern condenser mics, such as Audio-Technica’s AT4050, offer a figure-8 pattern and add a ton of utility to your live mic locker.

Often, if you’ve gone to the trouble of adding overheads, then you’ll want to single out the ride and the hi-hat as well. You have a few options for both, and it’s all up to personal preference. A common approach to the hi-hat is to stick a dynamic microphone below it, pointing up at about a 45-degree angle. This lets you cover the hats comfortably while minimizing bleed from the snare.

Another approach is to take a pencil condenser and point it perpendicularly at the hats, right at the plane where the two cymbals come together. You don’t need a lot of gain from this mic to add a bit of air and presence to the hats and capture some of the nuances the other method misses. Samson C02s are a great choice for these. They come as a pair, and they’re cheap enough that you won’t be heartbroken if one gets whacked by the drummer.

In a similar way, sticking a pencil condenser on the ride can provide a nice accent where needed. You’ll need to make sure you have enough clearance to avoid getting your mic clobbered when the drummer splashes the ride, but you don’t have to mic the whole ride to get great results. Usually a mic pointed right at the bell will do the trick, and you can stick this mic under the cymbal to reduce the visual impact of adding yet another mic.

On that note, it may be tempting at this point to start throwing extra mics up on other percussion instruments. Unless you’re dealing with Terry Bozzio or Neil Peart, you probably shouldn’t worry about miking up a bunch of percussion instruments unless there’s a dedicated percussionist.

If there are instruments like triangle, finger cymbals, mark tree, or wind chimes, have the drummer position them so that the existing overhead mics will pick them up. For live miking, simpler is usually better.

Three Simple Rules
We hope you’ve enjoyed these insights into live microphone placement. If there are only three things to take away from this article, let them be these:

Less is more. You’ll get the best results when you remember that live miking is about boosting the things that need to be louder, not sticking microphones everywhere and pushing up faders.
Feedback is the enemy. Get your microphones close to the source to get as much direct sound as possible. The better the direct sound to noise ratio you get, the less you’ll have to worry about feedback.
Be patient. It’s worth setting up earlier and spending the time to find the sweet spots on amps and drums. As always, it all comes down to trusting your ears and using your best judgment.

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