Urgent Help: Advice Recording a Choir (16 Members) in a Cathedral 9 Second Echo

[Craig McKenna]

Hi All,

I have just been contacted to record a choir on Thursday evening. As of now, I have only ever filmed weddings, proposals and tutorials. This will be my first time recording within a cathedral with a 9-second echo. Having spoken to the person hiring me, she has stated that she will be positioning the choir in front of the altar, in a semi circle. As there are 16 members, I imagine that this will be in two lines of 8. I asked if there would be an audio engineer present, but the lady said that unfortunately there would not be one. The cathedral, which can be seen below, has a nine second echo and will be empty during the performance, as they are closing the cathedral for the video to be shot.

http://www.cathedralconcerts.org.uk/...6_orig.jpg?311

My question regarding this, is how to capture the audio so that it is pleasing for the viewer? I have been through a couple of threads that have already posed similar questions, as well as some YouTube tutorials and a helpful visit to the Shure website. The problem I have is that all of my gear is dedicated towards recording weddings.

My current gear list:

1 Master Light Stand (Manfrotto)
1 low level mic stand
Three Sony M10 Recorders
2 TASCAM DR07 MK II Recorders
1 Zoom H5 Recorder
3 SANKEN COS 11D Lavalier Microphones
1 Sennheiser 416p Shotgun Microphone

I am only charging the client a small amount of money, as I realise that my expertise lie elsewhere, and this is a good opportunity to stretch my learning and understanding of audio.

I guess my main question is, do I require buying three mic stands and mics in order to get the best audio possible? The lady suggested using one pointing left, one pointing centre and one off to the right. The problem is, I only have a small budget of around £500 that I'd be willing to separate with at this moment in time, as I already have a deficit where equipment spending is concerned.

Thanks to anyone who can offer a solution, or advice that I should be watching out for!

Kind regards,

Craig

[Richard Crowley]

This is a VIDEO shoot as well as an AUDIO recording? How many cameras? What kinds of restrictions (if any?) on visible microphones or stands? What is the intended motivation/purpose/intent of this video recording?

The photo makes the space appear to be enormous, so it seems impractical to try to "fly" anything, either horizontally or vertically.

You don't appear to have ANY suitable microphones according to your list. How TALL is your "Master Light Stand"?

Reasoning: you could use a "single point" mic technique (ORTF, X-Y, M/S, etc.) and a single tall stand. But that stand would need to be essentially in the center, perhaps immediately in front of or behind the conductor. That is frequently a problem with good video angles where people think that a mic stand in the center of the frame is distracting, etc.

https://en.wikipedia.org/wiki/Microp...ereo_recording

[Richard Crowley]

Do you have access to the venue during a rehearsal? How early can you get in to set up? Especially in such an enormous space with such a long reverb time, and especially if you have little experience micing this kind of performance, you need all the time you can get to move the microphone(s) around to get the optimal pickup. We typically use the venue as part of the "instrument" to achieve a balanced direct/reflected "soundscape" in the recorded tracks. That typically takes some time (hours) to move mics around during the rehearsal to identify the best location.

With reverb that long, you may have to use closer microphone distance than we would normally use in a venue with more conventional acoustics. The distance between the source (choir) and the microphone directly determines the ratio of direct/ambient sound. And in this case it would seem that you will have an overabundance of ambient sound.

[Craig McKenna]

Originally Posted by Richard Crowley

This is a VIDEO shoot as well as an AUDIO recording? How many cameras? What kinds of restrictions (if any?) on visible microphones or stands? What is the intended motivation/purpose/intent of this video recording?

The photo makes the space appear to be enormous, so it seems impractical to try to "fly" anything, either horizontally or vertically.

You don't appear to have ANY suitable microphones according to your list. How TALL is your "Master Light Stand"?

Reasoning: you could use a "single point" mic technique (ORTF, X-Y, M/S, etc.) and a single tall stand. But that stand would need to be essentially in the center, perhaps immediately in front of or behind the conductor. That is frequently a problem with good video angles where people think that a mic stand in the center of the frame is distracting, etc.

Hello Richard,

Thank you so much for sharing your expertise. By the sounds of it, this is a last minute edit to gain some usable footage to support the choir's album release.

This is a video AND an audio shoot - with only me at the helm. I am considering two-three cameras. I will have a set wide angle shot, along with a close up that I will change periodically throughout the shoot. The final camera may be aimed at the conductor. I am considering shooting 4K with the wide, as I'll be able to do a pan in post. As well as this, I'm considering getting some venue shots, where I can cutaway to other angles. As the building is quite amazing structurally, I think I'll be able to get some nice symmetrical angles.

As far as I'm aware, there are no restrictions. The cathedral is closed for the performance, and the client has informed me that she usually uses a three mic setup in front of the choir, which sounds as though it would be quite invasive, and therefore, I believe I will have free reign as to where to position my gear. I don't know if she has done this personally, or an audio engineer has done this for her previously, as she's unable to provide me with the same setup that she describes.

I believe the purpose is a promotion for their CD release, which sounds as though it is very nearby. My guess is that they had a last minute idea, and I'm hoping that they will be going through with the idea that they currently have of rehearsing on Wednesday evening. If they do so, I will be there.

My Manfrotto Master Stand can go to 4 metres. I figured that my mics would be pretty terrible for this shoot - so much of wedding videography is based on isolating a given area, whereas this situation is opening yourself to the talent. This is why I'm willing to invest for the shoot, as I'm sure this won't be the only situation I run into where I need a more open pick up pattern.

I wouldn't mind using a single point mic technique. Would you be able to recommend a microphone of sorts to complete a recording such as this? I'll research the technique as much as possible.

Alternatively, would you blow the budget in order to get three stands and three mics? I dislike this option... it's not really a great option for me, really. If I got a clamp, I could possibly use two microphones in the same positioning (behind the conductor) so that one runs as a back up?

Thanks again, Richard! The X Y setup looks like a good shout. I've looked at some cardioid microphones, and I'd certainly be willing to purchase two for this shoot, if you can recommend some in the $300-400 range.

Thanks again - super helpful!

[Richard Crowley]

If this is a promotional "music video" then why not use the same "music video" production tricks as perfected for more contemporary "popular" music?

i.e. play back the release recording and have the choir "lip-sync" to the recorded performance (which they should be quite familiar with). That way, the audio track on your video will be as perfect as their audio recording release. I am quite serious. This is not a frivolous suggestion.

By "lip-sync" I don't mean silently "miming" the action of singing. I mean that they sing-along with their own recording, but you don't need to buy/hire/borrow any microphones, stands, etc. And you can concentrate on getting great video without any worries about trying to reproduce their probably great audio recording with insufficient resources.

[Craig McKenna]

Originally Posted by Richard Crowley

Do you have access to the venue during a rehearsal? How early can you get in to set up? Especially in such an enormous space with such a long reverb time, and especially if you have little experience micing this kind of performance, you need all the time you can get to move the microphone(s) around to get the optimal pickup. We typically use the venue as part of the "instrument" to achieve a balanced direct/reflected "soundscape" in the recorded tracks. That typically takes some time (hours) to move mics around during the rehearsal to identify the best location.

With reverb that long, you may have to use closer microphone distance than we would normally use in a venue with more conventional acoustics. The distance between the source (choir) and the microphone directly determines the ratio of direct/ambient sound. And in this case it would seem that you will have an overabundance of ambient sound.

I've only just seen this - thanks for another response! I have asked this, and they are hoping that a rehearsal will be on Wednesday. If so, I'm there. I can get to the venue around 5:30pm at best. That gives me 90 minutes before the performance. The choir will be practising from 6:30pm onwards, so if I can get all my gear set up within that hour, or thirty minutes if time is tight, then I will have thirty minutes to monitor the sound and get the best possible audio. Unfortunately, I don't have hours. I am working during the day, and as this is a short notice gig, the only thing I could do would be to go to the cathedral on another evening and hope that a choir is performing and that I can get a practice in.

OK. I have read on the Shure site that it is great to have a high point and to aim downwards. In many ways, I think the client understands the difficulty that the venue presents, and probably won't have an incredibly high expectation of the audio itself. They seem more focused on having great footage. However, as a videographer, I am well aware that more than 50% of the enjoyment will come from the audio in this recording, and I need to do my best, given the time and experience that I have.

If I need to be as close as possible, am I better off going for a three mic stand, three microphone and recorder setup? I think I'll be breaking the bank for this setup though, and it really isn't the time to be doing so.

Thanks again!!!

[Seth Bloombaum]

Rent!

And do consider Richard's suggestion that they lip sync to a recording; that's probably the best advise under the circumstances and considering the limited depth in audio gear and knowledge.

[Craig McKenna]

Originally Posted by Richard Crowley

If this is a promotional "music video" then why use the same "music video" production tricks as perfected for more contemporary "popular" music. i.e. play back the release recording and have the choir "lip-sync" to the recorded performance (which they should be quite familiar with). That way, the audio track on your video will be as perfect as their audio recording release. I am quite serious. This is not a frivolous suggestion.

Thanks Richard. After reading the client's emails again (exchanged quite a few today) I can confirm that it seems the forthcoming CD release is yet to be recorded, which means that they must have an extremely fast turnover time if that 'forthcoming' CD is going to be released any time soon!

Your solution sounds great, but I definitely wish to do my best with the audio recording as well. I may get back in touch with the client to discuss this, as it makes a lot of sense. I could still get them to sing, and then sync in Plural Eyes once the recording has been made.

Originally Posted by Seth Bloombaum

Rent!

And do consider Richard's suggestion that they lip sync to a recording; that's probably the best advise under the circumstances and considering the limited depth in audio gear and knowledge.

Thanks Seth. I'm uncertain of good businesses to rent from in the U.K, but I'll consider it. However, I am happy to part with a reasonable amount of money, so that I can reuse the gear in the future.

I wish they had the recording finished now. I may suggest to the client that it may be advantegeous to postpone until the recording has been made. Despite this, there may be a reason that they need the recording now, as it seems like a rush.

[Dave Blackhurst]

Hmmmm, haven't shot audio in that sort of scenario, but have run audio plenty of times...

First, that "room" was likely to have been engineered for a "full or nearly full house", the echos will be a nightmare, most likely, due to the lack of sound absorbent bodies... not an idea situation acoustically, as your "9 second echo" indicates.

Second, since this is a closed set with no audience, are they trying for a "live" feel, or is there any chance they have previously recorded audio and could "lip sync" the visual side of the performance? Yeah, I know lip sync is evil, but might be less so than that "live" room.

After those "scary" observations, I see a ray of hope - since this is a closed set, I presume you'll have the opportunity to re-take as needed and also sound check (extensively perhaps, unless you've got a "bit" of audio experience). Are they doing a whole "set", or just one or a couple songs?

Aesthetically, you're going to have mics visible, which is a negative, since as Richard noted, no way I can see to "fly" mics as would be "proper" in a scenario like this.

Is there a rental house where you could get proper mics? You'll need some mics that are directional, and able to get them fairly tight in to the "talent" (aesthetics again...) due to that echo - you're probably also going to want a "room" audio track (Zoom?) to mix in for a live feel in post.

Mic placement (and selection) is an art, familiarize yourself with it as much as you can, that will give you a fair chance! I've run audio plenty of times in "nightmare" rooms, most times dealing with someone else's "setup", so this brings flashbacks... surprisingly tiny adjustments of angle and position can have huge effect on the audio...

The best way I can describe this is you should try to get mics reasonably close in for as "dry" a sound of the choir as possible (2-3 mics with proper placement may cover you, don't think trying to mic each member is practical...), then add ambience in post from a secondary "room" source - at least that would be what I'd try for, the less "room" in the main audio tracks, the better.

See about getting needed mics and stands, and make sure there is time for "sound checks" - have headphones so you and the choir director can listen to results and correct as much as possible before rolling the video side of the equation (in order to make a dynamic video, you'll be plenty busy there as it happens!).

Not sure if there's any way to get the mics as Richard suggests in a single place where it would give you a fighting chance of hiding them, while still getting the desired audio quality, but that's definitely a possibility to consider.

Keep in mind that even an "audio engineer" would probably find that room a bit of a nightmare... so do your best, and hope it works out! I'm guessing they really LIKE the echo and "ambience", and are hoping to capture that magically onto video in one pass... it's going to take some setup time if that's at all possible, but with a little luck and proper mics, you might be able to pull it off!

[Richard Crowley]

It wasn't clear whether this was their usual recording venue? Can they hire the recording people to come in and do the audio recording at the same time (or you shoot video of the recording session itself)? That way you can take advantage of the gear and experience of their audio recording provider.

[Craig McKenna]

Originally Posted by Dave Blackhurst

Hmmmm, haven't shot audio in that sort of scenario, but have run audio plenty of times...

First, that "room" was likely to have been engineered for a "full or nearly full house", the echos will be a nightmare, most likely, due to the lack of sound absorbent bodies... not an idea situation acoustically, as your "9 second echo" indicates.

Second, since this is a closed set with no audience, are they trying for a "live" feel, or is there any chance they have previously recorded audio and could "lip sync" the visual side of the performance? Yeah, I know lip sync is evil, but might be less so than that "live" room.

I'm definitely going to email the client and ask this. At least if she knows that this is an option and turns it down, then she knows what it's going to sound like... having recorded there many times themselves, I'm guessing they know very well how difficult this is going to be to capture.

Originally Posted by Dave Blackhurst

After those "scary" observations, I see a ray of hope - since this is a closed set, I presume you'll have the opportunity to re-take as needed and also sound check (extensively perhaps, unless you've got a "bit" of audio experience). Are they doing a whole "set", or just one or a couple songs?

Two songs. 10 minutes. They're hoping it won't take too long, but as you've stated, that's heavily dependent on the audio captured.

Originally Posted by Dave Blackhurst

Aesthetically, you're going to have mics visible, which is a negative, since as Richard noted, no way I can see to "fly" mics as would be "proper" in a scenario like this.

I guess so... if I did go with the X Y recording, with two cadioids not too far from the talent, I may be able to get a wide and a close up that avoids having them in the frame? I'm guessing this would be a bonus to them, as the focus seems to be on video much more so than audio.

Originally Posted by Dave Blackhurst

Is there a rental house where you could get proper mics? You'll need some mics that are directional, and able to get them fairly tight in to the "talent" (aesthetics again...) due to that echo - you're probably also going to want a "room" audio track (Zoom?) to mix in for a live feel in post.

Not that I know of, but I have a friend who I can contact who has been in the industry for a decade or so... I'm sure he'd be able to advise me of a place to rent... that said, I'd rather buy. I want to make the most of audio equipment, and I'm sure it'll pay for itself long term. That said, there's no way I'm affording more than £1000 equivalent.

How would you propose mixing the 'room' track with the talent?

Sorry if this is a stupid question.

Originally Posted by Dave Blackhurst

Mic placement (and selection) is an art, familiarize yourself with it as much as you can, that will give you a fair chance! I've run audio plenty of times in "nightmare" rooms, most times dealing with someone else's "setup", so this brings flashbacks... surprisingly tiny adjustments of angle and position can have huge effect on the audio...

I'll try to do more reading on this, as I am only used to dealing with dialogue. I managed to pick up surprisingly decent audio from a proposal film that I shot by positioning a lavalier mic into a wall and directing it towards the unknowing client... but that's not going to help me here.

Originally Posted by Dave Blackhurst

The best way I can describe this is you should try to get mics reasonably close in for as "dry" a sound of the choir as possible (2-3 mics with proper placement may cover you, don't think trying to mic each member is practical...), then add ambience in post from a secondary "room" source - at least that would be what I'd try for, the less "room" in the main audio tracks, the better.

See about getting needed mics and stands, and make sure there is time for "sound checks" - have headphones so you and the choir director can listen to results and correct as much as possible before rolling the video side of the equation (in order to make a dynamic video, you'll be plenty busy there as it happens!).

Not sure if there's any way to get the mics as Richard suggests in a single place where it would give you a fighting chance of hiding them, while still getting the desired audio quality, but that's definitely a possibility to consider.

Thanks for all of these considerations. I definitely believe that the conductor would accept the X Y configuration from behind... just have to see...

Originally Posted by Dave Blackhurst

Keep in mind that even an "audio engineer" would probably find that room a bit of a nightmare... so do your best, and hope it works out! I'm guessing they really LIKE the echo and "ambience", and are hoping to capture that magically onto video in one pass... it's going to take some setup time if that's at all possible, but with a little luck and proper mics, you might be able to pull it off!

Thanks Dave! Really appreciate your time and thoughts!!!

Originally Posted by Richard Crowley

It wasn't clear whether this was their usual recording venue? Can they hire the recording people to come in and do the audio recording at the same time (or you shoot video of the recording session itself)? That way you can take advantage of the gear and experience of their audio recording provider.

Sorry. This is their recording venue. They are the choir of the cathedral (pictured in the original post and the place of the recording).

By the sounds of it, there is no chance of an audio engineer. I asked about that, and they said it wasn't available. I definitely realise that this would be the best case scenario though... I think I need to share these words of wisdom and see what their thoughts are... I really think 'my best' will be really appreciated by them. At least that's the feeling that I get...

Thanks again, Richard... if you could recommend what you would do if I were to go with an X Y recording situation in terms of microphones, I would appreciate it.

[Dave Blackhurst]

OK, you've got three monkeys all came to the same conclusions, it's a party! There was only the first response when I started typing, so I think we were all "channelling" the same audio guru advice!!

You're not going to get the mics "high" without compromising your video with at least one stand...

I'm thinking one stand, three mics, arrayed in a "V", maybe in front of the conductor (mostly hiding the stand?). You're actually going to need a mixer, or go with two mics and a stereo recorder, a third on another recorder if needed. How "wide" is the choir when set up, and what distances would you be working with for mic placement? I'm presuming with a semi-circle arrangement (thinking of a parabolic sort of thing) the choir could be fairly compact which might help you quite a bit. Remember you have to have sight lines to each vocalist (thus my comparison of a parabolic mic array "centered" in the semi-circle), to avoid blocking the audio - again why "high" is easier than "low" placement.

In the back of my mind I have this rather horrid feeling that the CD is a "dream" (one on a shoestring budget?), and somehow this shoot is about pushing that forward, making the audio sort of critical, but this really is a "cart before the horse" way of doing it, as has been pointed out. Live and studio productions are different animals, and there's a good reason that most music videos are shot to the STUDIO track, multiple passes, angles, etc., and edited to the final product...


Given the tight timelines, I'm just hoping you have the chance to do "re-takes", and proper rehearsal/set up for the actual shoot - if the audio IS crucial to their future CD being funded/produced, this is not the place to try to do a "whole set/album" shoot, but rather hire proper audio, and shoot ONE (OK, maybe two... or three) songs, multiple takes until it's so good it sends shivers down the spine... and THAT takes a combination of science, art, talent and luck on the best of days!

[Craig McKenna]

Originally Posted by Dave Blackhurst

OK, you've got three monkeys all came to the same conclusions, it's a party! There was only the first response when I started typing, so I think we were all "channelling" the same audio guru advice!!

You're not going to get the mics "high" without compromising your video with at least one stand...

I'm thinking one stand, three mics, arrayed in a "V", maybe in front of the conductor (mostly hiding the stand?).

How can I attach three mics to one stand?

Originally Posted by Dave Blackhurst

You're actually going to need a mixer, or go with two mics and a stereo recorder, a third on another recorder if needed.

I could purchase a H6 with three mics if necessary.... what would fit the bill though, as a great sounding mic?

Originally Posted by Dave Blackhurst

How "wide" is the choir when set up, and what distances would you be working with for mic placement? I'm presuming with a semi-circle arrangement (thinking of a parabolic sort of thing) the choir could be fairly compact which might help you quite a bit. Remember you have to have sight lines to each vocalist (thus my comparison of a parabolic mic array "centered" in the semi-circle), to avoid blocking the audio - again why "high" is easier than "low" placement.

Makes a lot of sense... thanks! I imagine they're either going to be 2X8 or 3X6.

Originally Posted by Dave Blackhurst

In the back of my mind I have this rather horrid feeling that the CD is a "dream" (one on a shoestring budget?), and somehow this shoot is about pushing that forward, making the audio sort of critical, but this really is a "cart before the horse" way of doing it, as has been pointed out. Live and studio productions are different animals, and there's a good reason that most music videos are shot to the STUDIO track, multiple passes, angles, etc., and edited to the final product...

Given the tight timelines, I'm just hoping you have the chance to do "re-takes", and proper rehearsal/set up for the actual shoot - if the audio IS crucial to their future CD being funded/produced, this is not the place to try to do a "whole set/album" shoot, but rather hire proper audio, and shoot ONE (OK, maybe two... or three) songs, multiple takes until it's so good it sends shivers down the spine... and THAT takes a combination of science, art, talent and luck on the best of days!

Yeah.... I knew that asking here would be the right choice, I just don't have the experience in order to pass this kind of information on yet when the client gets in touch... I knew that it'd be a complicated one.

I'm going to email the client again.

Thanks! If you could give me an idea of what you would consider buying on a budget that is a maximum £1000, I would really appreciate it... and maybe even one that is £500... assuming that you're as knowledgeable on your gear, as you are on your audio skills.

Really appreciate your time!

Thanks again!!!

[Dave Blackhurst]

OK, two songs, 10 minutes finished product... they are doing a "demo tape"... with little or no clue, but that's OK... it happens, been there, have a t-shirt collection...

Keep in mind that for 10 minutes of "finished" product you could be looking at a couple HOURS of retakes, especially if this is being shot live. Unlike a wedding or event video where you get one pass, and take what you get... a demo tape needs to have polish, no flaws, it's got to be good. If the talent is good enough, it could be almost a one pass affair, run multiple cameras/angles and cross your fingers - 4K will give you some advantages (pan/crop in post for wide/close), but think out what angles you want - I'd say at LEAST three camera positions, I'd probably have 3-5 and a manned camera, so you're on the right track! Keep the cameras rolling, take as many "takes" as needed - you may even be able to do some editing magic in post from different takes!

Back to audio...
An X/Y setup should be OK depending on the width and arc of the choir (parabolic again), if the room is dark, you might be able to place fairly close behind and above the conductor and get away with it, with minimal visual impact - otherwise lower and in front of her may work - experimentation and time are your friends here. "Room/ambient" can probably come from that Zoom - find a place a bit further back - walk the room and look for a "sweet spot" during the practice - there will be good "spots", bad spots, horrible spots, and likely a few really insanely great spots (I'm presuming from the photo that the cathedral was engineered for acoustical quality, as are many modern venues). Mix the ambient in in post - a good pair of cans in post may be as critical, or more than, the mics...

First you've got to capture it, but the mix is also going to be interesting - I'm guessing they will want a 5.1 mix... whether they even know what that is or not, you'll be after a "surround sound" mix in the final product to best show the talent, and you want to mix to make it sound like the viewer is IN that room with all the sonorous beauty of the echo/reverb! The joyous part is you have to have a fairly "dry" source from close in to the choir... and the ambient to mix to taste in post!

Since you've got a friend in audio, I should think you'll be able to "borrow" what you need (most audio guys are good that way <wink>) rather than rent.

[Bruce Watson]

Originally Posted by Craig McKenna

I have just been contacted to record a choir on Thursday evening. As of now, I have only ever filmed weddings, proposals and tutorials. This will be my first time recording within a cathedral with a 9-second echo.
...
My question regarding this, is how to capture the audio so that it is pleasing for the viewer?

Oy. Audio, especially stereo, is considerably more difficult that video, including multi-camera video.

This particular space looks quite challenging. None of the "usual suspects" when it comes to reflections. If it behaves like some of the capital rotundas I've been in, it could just be a nightmare from a sound recording standpoint. I'd have to be there to know.

Since you are clearly in over your head and want some help, here's what I suggest. I'd just try to avoid any thoughts of stereo -- you aren't charging them much you say, so don't give them much. Go with mono sound. Much easier.

Then I'd gaff tape one of your lav mics (the COS-11D is an omni, just what you need) onto the baby pin on your light stand, point the capsule down, about 45 degrees relative to the riser, and raise it off the deck somewhere around 3.0 m (your Manfrotto stand maxes out around 3.6m, so somewhat less than full extension should get you there). Position it so that it's at the focal point of the curve that the group makes (gather around the mic boys and girls), or a little closer in (so that all the voices are more or less equal-distant from the mic). The mic should now be pointing about midway between the two lines of singers, but it's an omni so the exact orientation isn't really all that critical.

Then, record the rehearsal, just like you would record a groom (peaks around -12dBfs, yes?) Every time they take a break, you listen to what you just recorded (use your headphones) and decide how to adjust your setup. How? What you're listening for is:

1) Does the group give you a balanced sound, and can you hear all the various voices. In particular, can you hear the basses and the sopranos without one being a lot louder than the other? The cure for this is often rearranging the group to put the weakest sounding members closer to the mic. But the conductor usually takes care of this kind of balancing. This shouldn't really be a problem for you, but you have to check it anyway because you're the guy doing the recording.

2) Do you hear a good balance between the direct sound of the singers and the reflections from the room? This is classic signal-to-noise ratio. If you get too much noise (room) then you need to get closer to your signal. So lower the mic, or push it into the group a little more, etc. You may well find that you want the mic lower, like maybe just 2.0 m -- just to control the long reverb tail you say this room has. If you're going to make a mistake here, make it in favor of a dryer (less reverb) sound. Better to be too close than too far away, especially in this building.

There ya go. That's it. Keep it simple. Really simple. One mic. One stand. One mic position.

And yes I'm well aware that the mic stand will be in your shot. But there's only the one stand, and it's tall and very thin. And... it's the only choice you have given the time available and the equipment available. So put it up where you need it without asking, and if anyone complains tell them (in the nicest most diplomatic way of course) that it's either this or sucky audio (which has the amazing advantage of being the truth).

Then, shoot around the stand. This is one reason to keep the mic above their heads -- it keeps the mic out of frame for your video, and that's a good thing for the video.

Finally, you may have to apply a little post processing to the audio. The COS-11D has a significant high frequency rise because it's designed to be used under clothing. So you may need to apply a little of the opposite curve via a parametric EQ if the high end sounds too bright or harsh. Small price to pay for avoiding the purchase of a mic that's more appropriate for this duty, yes?

There ya go. Good luck with it, and have fun.