Of Mics and Monitors: Live Sound Reinforcement Tips for Choirs

“What am I supposed to do with this?!” It’s not so much the question as it is the anxious look on the faces of so many of the wonderful volunteers I’ve had the privilege of working with over the years. It usually happens right after they see the mixing console with all of its knobs and buttons or the web of cables strewn about the stage.

Setting up mics for a choir and adequately reinforcing the sound from overhead microphones can be one of the most challenging propositions for the church sound system operator. So, if you’re either a church tech training a crew of inexperienced but eager volunteers or a volunteer facing the challenge alone, help has arrived.

Placement

An overhead or boundary mic is often placed at a distance from the singers in a choir. This can greatly increase the possibility of microphones picking up more background noise from the stage than the desired sound from the choir. And if there are main loudspeakers nearby, it’s an easy trigger for a feedback loop, a sure sound of trouble.

Let’s say the choir dynamics and stage volume are under control. The next thing to consider is the physical placement of your microphones. Distance is the key here—both distance from the mic to the choir and the distance between microphones.

When multiple overhead microphones are used to mic a choir, as is often the case, you need to use a basic rule when placing them so that there is limited interference and among the mics. The basic formula for properly miking a choir (or any group) is the 3:1 Rule.

Example

Let’s say Mic 1 is positioned 3′ from the nearest choir member.

Mic 2 should then be placed 9′ from the Mic 1 location. Mic 3 should be placed 9′ from Mic 2.

Put in mathematical terms, a second microphone should be placed three times the distance from the first microphone as the first microphone distance is from the sound source. (See the diagrams below.)

Distance Ratio for Micing a Choir

Example of Bad Distance Ratio for Micing a Choir

Most sound engineers choose to place microphones slightly above the choir and aimed toward the center row. This depends on how large or small the choir is and the way they’re physically positioned. Experiment with different microphone positions and work with the choir director to see what mic placement sounds most natural.

Interference when using multiple microphones

If multiple microphones are placed too close together, there will be interference between the two different mixed audio signals. This interference results from the different timing and “phase” of the audio signals being mixed together.

You can experiment with this yourself by placing two microphones near each other and presenting a single audio source, ideally something with a single tone or even “white noise.”

As you move one of the microphones closer to or farther from the first microphone, you’ll hear a pronounced “warping” of the mixed audio content. This phenomenon, called comb filtering, is the result of the same signal reaching two different microphones with a difference in timing and volume level. The closer microphone receives a louder signal at a particular moment. The more distant microphone receives a quieter and slightly delayed signal than the closer microphone since it is farther away from the audio source.

Polar patterns and cartridge types

When recording choirs, an omnidirectional or cardioid pickup pattern can be a good choice. I’ve found, however, that in most live sound reinforcement scenarios, you’ll benefit from having a much tighter pickup pattern, like that of a supercardioid or hypercardioid microphone. Microphones with narrower pickup patterns capture less ambient sound and are far more feedback-resistant.

You also may want to consider a condenser microphone as opposed to a dynamic microphone since condenser microphones are better at picking up sound at a farther distance than dynamic mics. But remember, condenser microphones require phantom power, either from batteries or the mixing console.

Overhead mics, like the Shure MX202, often are used for choirs. Most also can be mounted on stands so that you can place the microphones exactly where you want them.

Less is more

One of the most common mistakes when miking a choir is the use of too many microphones. This is bad for two reasons:

  1. Multiple microphones that are placed too close together can cause comb filtering (remember to follow the 3:1 rule).
  2. More open microphone channels increase the potential for feedback.

Use the minimum number of microphones to achieve the most natural reinforced sound possible.

What about monitors?

Mixing monitors for the choir can be a challenge as well. It’s important to consider monitor speaker locations relative to mic placement and physical choir positioning.

You’ll likely want to limit the overall volume of the mix in the choir monitors so that the choir mics pick up more choir and less monitor content. And never mix choir mic channels into the choir monitors; it’s a sure way to cause feedback.

Another important aspect of mixing for the choir is to include them in the main mix. Listen to the way the choir sounds in the room without reinforcement. Smaller rooms or more acoustically live environments may require much less choir reinforcement than you might initially suspect.

I always find it helpful to mute and unmute the choir mics while the choir is singing during a soundcheck to hear the difference between their natural volume level in the room and through the loudspeakers. It may be helpful to work with the choir director or worship leader when fine-tuning your choir mix since they know how their choir should sound.

Fear not

Don’t be afraid of making mistakes. They’re an important part of the learning process. You will always be learning.

Just make sure you dedicate time to developing your skills in an environment—choir practice for instance—that will not be at the expense of the congregation. Save them from your trials and errors. They deserve to hear your best.

If you need more helpful tips for church audio, my book and website Great Church Sound will be a valuable resource for you.

Header image – Historyworks under Creative Commons License 2.0

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James Wasem

James Wasem

Fascinated by sound and electronics from a young age, James Wasem figured out early that his love of music and technical gear made sound engineering and systems integration a natural pursuit. He’s spent the last 20 years touring in bands as a drummer and mixing live sound for churches, schools and theaters. He’s also an audio systems designer and the author of Great Church Sound.

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9 Comments

  • Nathy says:

    If you have the choir facing the mains how do you position the mic either suspended or on stand?

    • James Wasem says:

      Great question Nathy. I had a very similar issue when miking a church choir a few years ago.

      Option 1: If your loudspeakers are behind the choir and pointed at the microphones, you can hang the microphones and point them down. Try to use a very tight hypercardioid polar pattern to help reject any audio coming from the loudspeakers.

      Option 2: If your loudspeakers are pointed toward the back of the microphones, then you’ll want to try a cardioid pattern mic so that you have as much rear rejection as possible (supercardioid and hypercardioid patterns will pick up sound from the rear of the mic).

      Note: You’ll likely want to use a hanging mic configuration in both Option 1 and Option 2. The idea is to place the microphone so that loudspeakers are pointed towards the spot where the microphone pattern has the highest noise rejection.

      Option 3: If feedback is still a major issue, you may choose to use handheld mics and distribute them around the choir in an attempt to mix an even choir sound. A good handheld condenser mic may be useful for picking up three vocalists depending on location, pattern, and gain-before-feedback mixing considerations.

      I hope that helps. Good luck!

      For more info on coverage patterns, check out this post: shu.re/pGF2PY
      You may even consider using a shotgun mic if appropriate: shu.re/z52387

  • François says:

    I’ve been using a decca tree setup for choir. It has always served me well using sm81 to avoid feedback with the mains. For monitors, we’d either fly a pair in front of the choir or put them on stands.

  • James Wasem says:

    Great comments everyone! Here are some responses to your questions:

    ===

    1) Joey, you had a great question about the 3:1 distance rule.
    In the text and image example provided, the microphones are placed in a line 3’ away from the leading edge of the choir.

    The 3:1 rule indicates that multiple microphones should be placed apart, each of them 3x the distance relative to the shared distance from the audio source (choir).

    If the mics are positioned 3’ from the choir, then each mic will need to be 3 x 3 or 9’ from the next adjacent choir mic.
    The “Good Distance Ratio” image should help clarify this point.

    What you may recognize is that I failed to number the microphones in the example. I can understand your confusion in that case!

    If you have three mics in a horizontal row > 1, 2, 3, then:
    Mic #2 is 9’ from Mic #1
    Mic #3 is 9’ from Mic #2, which means that it is also 18’ from Mic #1

    Hope that helps!

    ===

    2) Jed, You had a couple items in your comment worth noting.

    #1: Choir mics mixed into the monitor channels. Yes, take them out of there (unless they are personal in-ear monitors).

    #2: Using an omni-directional condenser mic may be adding to your feedback issues. I would definitely recommend using a cardioid mic if possible. If that doesn’t give you the coverage pickup that you need, then use two cardioid or super-cardioid mics, but be sure to follow the 3:1 spacing rule. Use as few mics as possible to mic your choir.

    #3: Regarding the use of multiple SM58 mics on stands: Yes, you’ll want to follow the 3:1 spacing rule, but your spacing from each singer to each mic is hopefully pretty close (at least it should be for that type of microphone). If you have each microphone 6” from each singer, then the 3:1 rule allows you to have the microphones 1.5’ apart from each other. That’s pretty close! Your 2-3’ distance is just fine (if the singers are less than 1’ from the mic).

    #4: Regarding muddy vocals: The best way to clear up your sound with your vocal microphones is to make sure they are position close to the mouth (2”-4”) and then apply a little bit of EQ. Use your High Pass Filter on the console to cut frequencies below 80-100 Hz. Then use your sweepable mid or parametric EQ to find the sweet spot for each vocalist. This will vary by vocalist, so you need to listen to each person and dial in their voice accordingly. As a starting point, you can try a -3 to 6 dB cut somewhere around 200-800 Hz to remove some muddiness in vocals.

    Also, check out this great post on the Shure blog about vocal mic tips:
    http://blog.shure.com/vocal-miking-tips-2/

    Keep at it! You’ll get there.

    ===

    3) Carl, I can understand your frustration with the choir member spacing and monitor bleed-thru.

    It sounds like your choir spacing is pretty generous (side-to-side, and front-to-back).

    The 3:1 rule applies to microphones miking the same source in all directions. So you’d want to follow that spacing pattern in the side-to-side and front-to-back arrangements.

    That being said, I have personally violated this rule in some instances, and it’s been “ok”. You may also want to experiment with two mics in front and one mic in the back-center area (this would create a triangle when viewed from above).

    And if you’re looking to provide some extra clarity from the choir, you could trying giving out a few handheld condenser mics to various choir members (spaced evenly apart) and gradually mix in these mics with the overall sound. It won’t give you a “perfect” choir sound from a recording perspective, but it will let small groups of vocalists pop through the mix and may give you a reasonable result.

    Regarding your playback track monitor issue: The only way you can mitigate this is to make sure the monitors and not within the pickup pattern of the microphones.

    If you are using a cardioid capsule, then you’ll want to make sure the monitors are directly behind the mic capsule.
    If you are using a super-cardioid capsule, then there is a small rear lobe that picks up sound behind the mic, so the monitors should be off to the side a little bit.

    Playback tracks with choirs can be tricky, so you’ll have to experiment with mic/monitor placement and volume levels. The best general advice I can give you here is: keep your mics as close to the source as possible (noting the polar pattern of the mic), and only turn up the stage monitors as loud as they need to be for effective monitoring.

    Hope that helps!
    -James

  • SHELLEY HERMAN says:

    I specialize in sound reinforcement for barbershop harmony choruses, both men and women. I have been using side address, supercardioid ribbon mics for years. As a matter of fact they are made by SHURE. Unfortunately no longer!
    They are model 330 and I have nine of them. One of the advantages of the 330 is that it is a side address unit which can be directly hung from it’s cable, with an appropriate clamp device.
    Ribbon microphones are the best microphones for unaccompanied voice so the 330’s give excellent results under those circumstances.
    I also use a cardioid ribbon microphone for quartets. Unfortunately Shure never made one with a wide enough pattern for a quartet, so I use one of my RCA77DX’s for that duty. When properly adjusted the have just the right coverage for all four members without losing any part.
    By the way, the 330’s are also very good in front of the brass section when reinforcing 1940’s style big bands.
    Now that ribbons are making a comeback, perhaps Shure could be convinced to develop a modern version of the 330.

  • Joey Daddario says:

    James,
    In the explanation for your 3 mic distancing diagram, I think you meant to say that mic 3 should be placed 9ft from mic 1 (not 9ft from mic 2 as written). Can you clarify for me?
    Thanks,
    Joey

  • Jed Dixon says:

    James,

    Thanks for the informative post. I have been wrestling with sounds issues for my church for some time now, and have all but given up on trying to provide sound reinforcement for the choir. We just can’t seem to avoid feedback through our single omni-directional condensor mic, but your tip to avoid mixing the choir mic channels into the choir monitors may point to the culprit. I will give it a try.

    Normally we don’t have a choir at all, but mainly use a group of five singers to lead the singing. They are split into a “4+1” configuration on the small stage, i.e. the lead singer alone at stage left, and the part singers clustered together at stage right, with stand-mounted dynamic (SM58) microphones placed approximately 2-3 feet apart. In reading your comments about mic separation and comb filtering, I wondered if perhaps we are violating the 3-1 rule and creating a muddy sound. Unfortunately We don’t have any good options for spreading the mics out, as the majority of the stage is taken up with a large projection screen. Any thoughts or suggestions?

  • Dale Mettee says:

    James, I too have done a lot of on site recording. Most of this was done many years ago when analogue recorders were in vogue. Today, I’m looking to getting back into it only this time using digital equipment. Instead of it weighing in at 70#’s, it weighs in at .5#, much better for an “older guy”.

  • Carl Brown says:

    What is the depth that a mic can go before adding another mic? Our choir is set up in three rows with chairs (unfortunately and for now) the depth of each row is 4 feet in depth creating a distance of about 8-9 feet from front to back singer. They are also much more spread out horizontally due to chairs. Right now I have three Shure CSM41’s across the front, but not exactly 3-1 (I will fix that).
    Also, we use canned sound for the choir specials and have two floor monitors and to side (choir) monitors and I am worried that the canned sound is also being picked up by the choir mics. I have asked local experts in sound and they haven’t a clue.
    It is extremely frustrating to have a 50 member choir disappear in sound on Sunday mornings

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