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TRACKING A SMALL CHOIR

 

Heavenly choirs sing to the Pacific Ocean high above Vancouver's Burrard Inlet

Heavenly choirs sing to the Pacific Ocean high above Vancouver’s Burrard Inlet

 

A small choir is the largest group of voices singing simultaneously that you are likely to encounter at home, and the odds are good that you will actually end up arranging to work with them outside the home, perhaps on location at a church hall or gym or yoga studio or some similarly large-ish space with (hopefully) rather more pleasant reverberation characteristics than your bedroom or living room.

Large choirs are simply too big for most home settings.  Just picturing having enough glasses of water on hand gives me a headache.

Let’s assume your space can fit enough people in without positioning people too close together, and with enough room left for air to circulate and people to not overheat.  You may well need a few music stands and some lighting, and I suppose a microphone stand or two might not be a bad idea since a recording is planned.

MICROPHONE SELECTION AND IMAGING CHOICES

Since choirs are made up of a number of human voices in a space singing together, it is very common to use condenser microphones.

These are relatively bright, and tend to flatter human speech and song by providing great intelligibility and clarity, having crisp highs with warm low midrange tones supporting them.   Due to the detail they can pick up, they are very well suited to capturing every nuance of an expressive vocal performance.

Ribbon microphones are also excellent choices, with a warmer, smoother and darker yet flattering sound.  There will be a little less high end detail than with condensers, and intelligibility of lyric can be an issue requiring careful positioning of the microphones.  However, the smooth, enveloping sound is very inviting and listeners can often prefer the mellow sound of ribbons to the intimate detail of condensers – it depends to a large extent on the requirements of the music.  The AEA R84 is a wonderful modern choice of binaural ribbon with a warm sound.

Generally speaking, a choir will benefit most from a stereo recording.  This is because they occupy a fairly large physical space, and to capture the sound properly it is best to maintain some distance from the choir, and position them so that the sound balance entering the microphone is precisely as desired.

If you put the microphones too far from the choir, then you will have too much room ambience relative to the direct sound of the voices.  This sounds roomy or boxy, and is far from ideal.  So, what to do?

The further you are from the choir, the more the acoustics of the room will dominate the sound entering the microphone(s).  Of course, the nearer you get to the choir, the more direct sound you will capture relative to the sound of the room itself.  Ideally, you want a balance of the two that favours the voices over the room sound, but is far enough from the singers that you get the choir’s sound as a whole, rather than favouring particular singers within the choir (unless you want to).

This principle applies to all recordings made of instruments or groups of people who take up a relatively large amount of physical space – such as a drum set or a choir.  Make your mike positioning decisions carefully, by managing the balance between room sound and the sound of the whole vocal group.

MID-SIDE MICROPHONE TECHNIQUE

The stereo Mid-Side microphone technique is very often used in classical and choral recordings.

This uses a mono Mid mic and a figure-eight pattern mic as the Sides.  It uses three channels in this way – one mono Mid mic in the middle and two hard-panned Sides obtained from a single binaural mic (usually a ribbon or suitable condenser) positioned at right angles to the Mid mic directly above it.

The ability to collapse the mix into mono is very important, and you want to still have a good solid sound when this happens on certain playback systems.  The M/S technique allows this, and more… because, when you are hearing them in stereo,  by altering the level of the Side mic relative to the Mid mic, you can make the stereo image wider or narrower AFTER the recording has been made.

Incidentally, this makes it very useful in television broadcast situations, especially when live events are recorded for later broadcast, since the recorded sound can be made wider or narrower as required when it’s in post-production.

Mono compatibility is excellent with this technique, and it provides a very naturalistic sound, which is very well-suited to classical and choral music.

AEA R84 passive ribbon mic - and it's handy padded protection cover, for when it's not needed.

AEA R84 passive ribbon mic – and it’s handy padded protection cover, for when it’s not needed.

The Mid signal is obtained by pointing a single mono mic at the sound source from the front, often a few feet above and slightly behind the choir director’s head.  This has a cardioid pattern for a choir, although with a much narrower, smaller sound source such as a single violin you may prefer a hyper-cardioid pattern.  The point is that it captures a good mono sound all by itself.  It’s panned up the middle of the mix.

A binaural pattern (figure-eight) microphone pattern is used as the Side signals, such as a suitable condenser or a ribbon microphone.  This is placed at right angles to the Mid mic, and directly above it.  The incoming mic signal is multed (duplicated in a digital system) so you have two versions side by side on identical tracks set to unity gain or at least equal level.  You pan the first hard left and the second hard right.  That’s 100% panned L and R.  As you raise the level of the Side signals from the off position upwards, the sound spreads from mono out into an increasingly wider stereo image.

Playing back the Mid track and both of the Side tracks together in stereo gives a very real, natural sound.  Raising and lowering the Sides signals will widen or narrow the apparent spread in stereo.  The lower the Sides are kept relative to the Mid mic, the more narrow the sound becomes

In a mono mix, the Side microphone signals (left and right) are discarded through phase cancellation (assuming they are each set at the same level), and only the Mid microphone signal remains.  Since the Mid signal is a mono microphone with a cardioid pattern, panned to centre in stereo, there is no phase issue when collapsed to mono and it plays back as a mono sound perfectly well.  The side signals are lost because they cancel each other out, provided they are kept at the same levels as each other to promote maximum cancellation, and thus do not affect the sound of the Mid mic.

HOW TO POSITION THE CHOIR

In a live concert, choir members are often huddled rather close together, due to the restrictions of space on a stage, or for visual reasons in performance.  In a studio recording, it helps to move the singers a little further away from each other.  People sing more freely, and it is easier to accommodate the various stands and cables and any headphones.

In performance, the choir are singing to an entire audience who are positioned in various locations throughout the venue.  In the studio, the choir are singing to the microphones, or more often at a choir director on a riser of some sort.  All of these are positioned at a fixed point or points relative to the choir, unlike an audience spread across a venue horizontally and even somewhat vertically.

Singers usually sing looking at the director’s position at his or her eye height, and a few feet above this spot may be a great place for a stereo microphone.  There will only be one or two or perhaps three microphones to consider, depending on the miking technique you use.  Position the singers accordingly.

Try to divide the choir into three rows, ideally.  If you have too many rows deep, you will need additional microphones.  This can easily cause phase issues when combining all these signals in a mix, which damages your ability to get a good strong balance in mono for the whole choir, and many forms of music playback systems are still mono even in the 21st century.

Form an arc of several singers in a row, each keeping a foot or two apart from each other, facing the choir director.  There might be up to seven singers in this arc given a very large choir, or at least very large for one that you might try to fit into a large home studio.  This forms a front row, curved in a broad arc in front of the microphones.  Add rows behind this as suits the size of the choir.

HEADPHONE ISSUES

Individual headphones are often required.   Naturally, this means having a lot of headphones for the session, and, if it’s a larger choir, quite a few headphone amplifiers or headphone distribution boxes as well.

Ultrasone S-Logic headphones

Ultrasone S-Logic headphones

The singers are most used to blending their voices in an acoustic setting, one where they will hear each other without any headphones.  This is a natural sound, where the performers balance themselves in large part, under the direction of a choir director.

The choir director may require a riser or podium of some sort.   This is so that s/he can be seen by all singers, including any in a second, third or even fourth row.  Getting the acoustic blend of their voices right means that they need to hear each other, and the ideal way is acoustically in the room.

They really do need to have a good sightline from the back rows to see the choir director, so be sure to take this into account as you position singers.

Headphones are often wanted, but this is balanced with the need to hear each other acoustically, so you will often need to provide single-cup headphones or allow singers each to use one side only of a normal pair.

If people are going to leave one ear-cup off, to help them confidently hit the right notes on key and get a good blend with their fellow singers, make sure you have given them a mono mix of any music they sing to, and that it is hard-panned to one side only, leaving only silence in the unused side.

In this way, you will be able to keep the noise floor down in the room by effectively removing headphone spill from the “off-ear” ear-cup, preventing audio spill from getting into the microphones.

The only caveat is that you must ask all singers to use the same side as the “on-ear” because if some singers want to use the left side and some singers want to use the right side, you will be back to square one.

FINAL THOUGHTS

Singers are not instruments of metal and wood – they are human beings!   Do check that all singers have what they need, and are ready to perform their best.  Aim for a friendly, supportive atmosphere and let the choir director maintain order amongst the choir members.

Bottled room temperature water is needed, but most singers think to bring their own.  Have some handy anyway.  Certainly do not give them ice-cold water, and preferably don’t let them have hot drinks either, since the vocal chords need to be relaxed and warm, and not coated in milky drinks or shocked into contracting by icy water.  Dairy products are not compatible with singing – no cheese or milk, please.

Last but not least, choir members in a recording situation will often need music stands, and, if you are lucky, one for every two singers may suffice.  A lot of cables and stands may be brought into play, and you don’t want people falling over things and you need space for everything.

You should also take care to avoid sound reflecting from music stands angled towards the singers mouths as you don’t want it bouncing back into the open microphones.

A simple piece of soft carpet or cloth placed behind the sheet music or written notes on the stand goes a long way to preventing that from becoming an issue.  The recorded sound may become a little metallic or boxy if this is ignored and it’s easy to prevent, so do take it into account for the best results.

Okay, well that’s about it for choirs…  join me next time for my upcoming blog post “Tracking Mandolins, Fiddles, Celtic or Bluegrass”.  Fun, fun, fun!

 

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