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What mic technique is used in this recording?

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What mic technique is used in this recording?

Postby george_vel » Mon Mar 12, 2018 10:30 am

Hello everyone,

I need your porfessional opinion on the recording shown below and how I can come closer to this superb sounding. :-)

This is a recording made by hyperion-records studio with Trinity College Choir performing "Only in sleep" - entire piece here: https://www.youtube.com/watch?v=fvPynMI6Umc

Now, I understand that a great performers and a great sounding place are major factors for such recordings, but folowing the video timeline, I have couple of questions and need your help:

1) 0:41 - 0:42: first view of mics setup
2) 1:25 - 1:32: clearer view on main LDC pair in the center and the rest 4 SDC spot mics
3) 1:49 - 1:54: top (bird) view of the whole ensemble and mics setup
4) 1:05 - 3:08: the whole choral sound - exceptional clarity of each part and excellent balance
5) 3:08 - till end: choral sound with "mmm - aaa - mmm" is still clearly present below the soloist (great mix positioning)
6) 4:55 - 4:58: view of the entire recording space

So:
1) What is this mic setup? Looks like there is a main pair of LDC (probably omnis) and there are 4 mics as spots to different choral sections (cardioids or again omnis?)

2) With such setup (let's assume 2 omnis with 4 cardoids) what is the risk of phase cancellations and sound issues, when mixing afterwards?

3) What is this setup where mics are so low positioned and close to the floor - especially the main spaced pair? I've expected the mics to be at least 1 meter above singers' heads, not literally at their feets.

As I am pursuing similar sound blend with our choirs, I want to find best combination of mics patterns and positioning, when the accoustics of recording place is good. Currently I have 2 stereo matched cardoids and want to know should I invest in omnis as well and how to use cardoids and omnis in parallel during recording session without getting phase issues.

Thanks a lot for your opinions and help :)
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Re: What mics techique is used in this recording?

Postby Sam Inglis » Mon Mar 12, 2018 10:41 am

I can't answer your questions about miking, but want to point out that that isn't a cathedral, it's the chapel of Trinity College Cambridge. It's not small, but it's a fair bit smaller (and in particular, a lot narrower) than any cathedral I know of.
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Re: What mics techique is used in this recording?

Postby george_vel » Mon Mar 12, 2018 10:45 am

Sam Inglis wrote:I can't answer your questions about miking, but want to point out that that isn't a cathedral, it's the chapel of Trinity College Cambridge. It's not small, but it's a fair bit smaller (and in particular, a lot narrower) than any cathedral I know of.
Thanks for your comment - I’ve removed “a cathedral” in the original post :-)
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Re: What mics techique is used in this recording?

Postby Hugh Robjohns » Mon Mar 12, 2018 11:18 am

george_vel wrote:1) What is this mic setup?

It's a collection of mics that appear to deliver a lovely sounding recording! I'd be slightly surprised if the whole sound was achieved with just those six mics -- I was expecting a slightly more distant main pair (because those front four mics would tend to over-emphasise the front of the choir) -- but I can't see one in the (low-res) wide shots. I don't know the acoustics of that chapel, though, and it could be possible to get everything on those six mics in the right acoustics.

With such setup (let's assume 2 omnis with 4 cardoids) what is the risk of phase cancellations and sound issues, when mixing afterwards?

Can you hear any phase issues or cancellations? The more mics, the lower the risk... (but the more confused the stereo image).

What is this setup where mics are so low positioned and close to the floor - especially the main spaced pair?

That's not a 'main spaced pair'. Those LDCs are essentially a single spot mic for the soloist but, by using two mics panned hard left/right, it provides a mono centre spot without collapsing the stereo image. It's a very common technique in classical circles. I'd be more worried about comb-filtering from reflections off the hard floor because the mics are so close to it.. so I suspect they are cardioids rather than omnis to help minimise that risk.

The mics are down there in order to avoid blocking the video sight-lines -- no more and no less. If you look at the end credits, the sound engineer is also credited as the videographer, so he probably placed mics specifically to make the video look good.

As I am pursuing similar sound blend with our choirs, I want to find best combination of mics patterns and positioning, when the accoustics of recording place is good.

What works in one place won't work in another. The talent lies in having a range of techniques in your tool kit and the ears to know which works in each situation.

And, always be very wary of what you see on a Youtube video -- it's not unusual to dub a separate recording over a video shot at a different time. Not saying that's definitively the case here, but I'd be cautious of making assumptions...

...want to know should I invest in omnis as well...

Omnis certainly have their uses and, if you don't have any, it might be a good idea to get some to expand your options. But don't expect to use them every single recording session.

... and how to use cardoids and omnis in parallel during recording session without getting phase issues.

It's not the combination of polar patterns that is the issue, its the number of mics and their relative distances.

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Re: What mic technique is used in this recording?

Postby george_vel » Mon Mar 12, 2018 2:24 pm

Hugh,
First of all, thanks for your detailed answer! :)

Hugh Robjohns wrote:
With such setup (let's assume 2 omnis with 4 cardoids) what is the risk of phase cancellations and sound issues, when mixing afterwards?

Can you hear any phase issues or cancellations? The more mics, the lower the risk... (but the more confused the stereo image).

Exactly, I am not hearing any issues and was wondering how it was achieved, since mics looks pretty close to each other. Lots of internet resources suggest "less is more" approach when recording a choir and I do not want to spend cash for useless setup of multiple mics.

Hugh Robjohns wrote:
george_vel wrote:
As I am pursuing similar sound blend with our choirs, I want to find best combination of mics patterns and positioning, when the accoustics of recording place is good.
...
And, always be very wary of what you see on a Youtube video -- it's not unusual to dub a separate recording over a video shot at a different time. Not saying that's definitively the case here, but I'd be cautious of making assumptions...

I also suspect that most likely recording here was done separately from the video shooting, but we can only guess.

Hugh Robjohns wrote:
george_vel wrote:
... and how to use cardoids and omnis in parallel during recording session without getting phase issues.

It's not the combination of polar patterns that is the issue, its the number of mics and their relative distances.

Well, this is what I am trying to figure out and try to get right for upcoming recording sessions we plan for this summer.
The place will be a church with full round architecture, wooden floor, around 10 000 cubic meters, reverb time approx. a little above 1 sec - in general, pretty nice accoustic for recording.

This is the setup I have in mind, but not sure it will work well:
https://drive.google.com/open?id=1Weuy6KuGitqcESBESWkrGmSXY_kcNHDl
, where:
- ORTF cardioids to capture main stereo image
- spaced omnis to reinforce baritone and bass sections, as well as capture natural space feeling
- distant XY to use afterwards for additional reverberation, if needed
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Re: What mic technique is used in this recording?

Postby Sam Inglis » Mon Mar 12, 2018 3:37 pm

The space you're describing sounds very different from Trinity chapel, which (like some of the other college chapels) is quite an unusual shape -- very high and long, but narrow, and entirely faced in hard stone. I've not recorded there but I imagine it would pose some interesting challenges, and it may be that (if the video is indeed live) the miking setup was chosen to compensate for the peculiarities of the space in some way.

There are just too many variables to know whether your proposed setup will work, but it's surely going to benefit from a bit of experimentation on the day, if you have time to do so. If your diagram is to scale then it looks as though the singers on either edge of the choir will be positioned beyond the edges of the ORTF pair's recording angle, which will make them sound as though they are bunched together hard left and hard right, so that is something to watch out for.
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Re: What mic technique is used in this recording?

Postby Hugh Robjohns » Mon Mar 12, 2018 3:44 pm

george_vel wrote:Exactly, I am not hearing any issues and was wondering how it was achieved, since mics looks pretty close to each other.

As I said, I wouldn't place too much weight on the looks... there may well have been a main stereo pair further back and out of shot, and those front mics may not have been used much or at all... You'd really need to track down the recording engineer and ask how he made the recording to know for sure. But if they were omnis it's quite possible that any phase-combing would have been diluted by the number of mics and their relatively close spacing.

Well, this is what I am trying to figure out and try to get right for upcoming recording sessions we plan for this summer.

Then you have time to experiment and find out what techniques work for the sound you want with your choir in that venue...

It's a good idea to have a basic plan of a reliable starting point, but most engineers have to develop the mic array for each occasion based on what their ears are telling them and their experience of how to address and correct any identified weaknesses.

There is no 'game-book' of specific mic setups to guarantee success. Every situation is different.

An ORTF array can give good results if the acoustics allow it to be placed appropriately, taking into account its stereo acceptance angle. However, if your diagram is accurate I fear it is much too close... Lots of people supplement ORTF with omni outriggers at varying distances, depending on the nature of the acoustics and sources.

I'm rather less convinced the XY array will give anything very useful as shown, and the image width it captures of the choir won't match that of the ORTF or omni outriggers....

If you think you want isolated room reverb for mixing then put the 'space mics' well back into the diffuse zone of the room where they can capture the acoustics (and potentially the audience) rather than the direct choir source -- there's no point in having the same thing on all the mics! That doesn't provide flexibility in mixing...

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Re: What mic technique is used in this recording?

Postby Ariosto » Mon Mar 12, 2018 6:43 pm

george_vel wrote:

The place will be a church with full round architecture, wooden floor, around 10 000 cubic meters, reverb time approx. a little above 1 sec - in general, pretty nice accoustic for recording.

Are you sure about the reverb time? Most churches are 2.5 to 4 secs.
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Re: What mic technique is used in this recording?

Postby george_vel » Tue Mar 13, 2018 12:23 am

Ariosto wrote:
george_vel wrote:

The place will be a church with full round architecture, wooden floor, around 10 000 cubic meters, reverb time approx. a little above 1 sec - in general, pretty nice accoustic for recording.

Are you sure about the reverb time? Most churches are 2.5 to 4 secs.

I am not sure as I did not measure it myself. I was told by one of the preasts about reverb time, but he might be wrong.

However, 4 secs looks extremely long to me...

This is a picture of the church - outside and inside (I’ve tried to embed the image, but it doesn’t work):
- Outside: https://goo.gl/images/oTA8YE
- Inside: https://goo.gl/images/nUAfCU
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Re: What mic technique is used in this recording?

Postby george_vel » Thu Mar 15, 2018 6:22 pm

Ok, Hugh, thanks a lot for your valuable advices. :-)
Let me clarify few things, so you can understand me better:
- I do not insist on many mics, I prefer to stick to “less is more” approach
- I am still learning and I am not a pro, consider it as a hobby
- I prefer proven stereo techiques, like X-Y or ORTF with cardioids as main pair and I am just looking for a way to make the bass stronger in the mix, hence omnis came into disussion
- the X-Y at the end of my picture is actually the zoom h6 stock mics - I may not use them at all and per your suggestion, I will not. But until I get SD Premix, I am using this recorder and I thought to make additional use of it.
- my pic is not exactly measured and scalable, so during sound check I expect main pair to be further away from choir, it depends
- and I am still not sure how to use omni outriggers correctly in order to increase bass section - the choir will be around 20 -25 people and if main pair is let say 2 meters from the choir, then following 3:1 rule, outriggers should be 6 meters away, which will end far away left and right after the choir

I know it depends and I can make checks, but any best practice advise would be great - especially in combining cardioids with omnis. There is a lot on gearslutz, like cardioids and omnis on one bar, spaced 67 and 47 cm, but I am really not confident what will be the end result with such setup in mine “not-so-experienced” hands :-)
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Re: What mic technique is used in this recording?

Postby Sam Inglis » Thu Mar 15, 2018 6:39 pm

Why do you feel you want to make the bass "stronger in the mix"? Omnis do have a deeper bass response than cardioids, but this would be more of an issue when recording something like a pipe organ, which might have useful musical information at 20 or 30 Hz. As long as the choir themselves are well balanced internally, you should have no difficulty capturing enough bass with cardioid mics, I'd have thought. Alternatively, you could use spaced omnis as your main pair.
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Re: What mic technique is used in this recording?

Postby george_vel » Thu Mar 15, 2018 7:17 pm

Sam Inglis wrote:Why do you feel you want to make the bass "stronger in the mix"? Omnis do have a deeper bass response than cardioids, but this would be more of an issue when recording something like a pipe organ, which might have useful musical information at 20 or 30 Hz. As long as the choir themselves are well balanced internally, you should have no difficulty capturing enough bass with cardioid mics, I'd have thought. Alternatively, you could use spaced omnis as your main pair.

Well, I guess because I heard couple of examples on the net where cardioids are compared to omnis and omnis sound somehow richer and more ... deep. And I read some people make different mic arrays or flanks and outriggers.
So, I am seeking to achieve best of both.

But reading you, guys, I’m starting to think that I am really heading into wrong direction... :-(
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Re: What mic technique is used in this recording?

Postby Sam Inglis » Thu Mar 15, 2018 7:30 pm

It's pretty hard to do a meaningful comparison of 'cardioids versus omnis' per se, because there are so many variables. If you use them at the same distance from the source, the cardioids will pick up a higher proportion of direct to ambient sound, and thus will tend to sound drier. And whereas stereo information in an omni pair is only derived from time-of-arrival difference, in a cardioid pair it's a mixture of intensity and time-of-arrival (or just intensity in a coincident pair). Both of those differences could be characterised as making omnis sound 'deeper' but it's a very subjective thing.
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Re: What mic technique is used in this recording?

Postby george_vel » Thu Mar 15, 2018 9:13 pm

Agree with you, that’s why theoretically cardios should be 1.7 farther away than omnis, so dry-wet sounding can be comparable.

But then what about proximity effect when using cardios? If they are 1.7 farther, bass section will really sound thin and weak.

Trying to minimize it by placing stereo pair closer will break the choral blended sound and different voices will start to appear.

I dont’t want to argue with you given my really modest knowledge - I want to learn to do it better, while at the same time making wise investment decisions for additional gear (if needed at all) to make things sound richer. At the moment I don’t have omnis.
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Re: What mic technique is used in this recording?

Postby Aural Reject » Fri Mar 16, 2018 9:40 am

I think perhaps you’re gettting a little confused about the proximity effect...

When you’re talking about using microphones at the distances you’re proposing you won’t need to take it into account - it’s only when you’re working close up that you need to think about it.
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Re: What mic technique is used in this recording?

Postby Hugh Robjohns » Fri Mar 16, 2018 11:56 am

george_vel wrote:I am just looking for a way to make the bass stronger in the mix, hence omnis came into disussion

This is more often a problem with the choir than the recording technique. It's sad but true that most amateur choirs lack sufficient male voices, and consequently the performance sounds bass-shy in real life.

And omnis don't 'add bass' -- and especially not for a choir! Any decent cardioid will be flat down to 40Hz or lower and no singer will generate anything sensible below about 100Hz, not even big-chested blokes! So you're not going to missing any low-end by using cardioids in front of a choir...

It is true that omnis often have an extended LF response, typically flat down to an octave lower than a cardioid -- say 20Hz or so, but clearly that won't make any practical difference in capturing a choir.

However, cardioids do introduce a certain phasy character than omnis lack, which may result in a preference for the latter when recording familiar and recognisable sounds like voices. Also, recording in stereo with omnis requires a spaced technique to capture time-of-arrival differences which gives a much more spacious low end character compared to coincident cardioids and that, again, is often preferred.

...and I am still not sure how to use omni outriggers correctly in order to increase bass section

They wont... as discussed. But they can potentially introduce a sense of spaciousness that the ORTF array lacks. There are no rules: you just adjust their width until you achieve the balance and character you seek for a given physical arrangement of choir and room acoustics.

...if main pair is let say 2 meters from the choir, then following 3:1 rule, outriggers should be 6 meters away, which will end far away left and right after the choir

You're getting yourself very confused here. The 3:1 'rule' is about minimising unwanted spill between mics intended to capture different sources in the same room -- but that most categorically doesn't apply here. You're not trying to minimise spill between the main pair and the outriggers because they inherently need to capture the same thing -- namely the choir!

There is a lot on gearslutz, like cardioids and omnis on one bar, spaced 67 and 47 cm, but I am really not confident what will be the end result with such setup in mine “not-so-experienced” hands :-)

It really will come down to using your ears, I'm afraid. That spacing range (45-70cm) is a workable range, but you might need to go even wider in some cases or even a little closer.

Several factors determine the optimal spacing. For example, the spaced pair of outriggers will capture a stereo image of their own, and that will overlay the stereo image of the main pair (ORTF or XY etc) when you add them to the mix. But if these two stereo images have different acceptance angles and spatial linearities the mix combination will suffer image blurring or confusion... That may be acceptable or not, depending on your preferences and expectations. Adjusting the width of the spaced outriggers will affect the stereo recording angle, and you can therefore optimise the matching of images...

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Re: What mic technique is used in this recording?

Postby Hugh Robjohns » Fri Mar 16, 2018 11:58 am

george_vel wrote:Well, I guess because I heard couple of examples on the net where cardioids are compared to omnis and omnis sound somehow richer and more ... deep.

As I mentioned above, I think you may be confusing the low-end spaciousness associated with spaced mic techniques as more low end energy, but it ain't necessarily so!

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Re: What mic technique is used in this recording?

Postby Hugh Robjohns » Fri Mar 16, 2018 12:09 pm

george_vel wrote:But then what about proximity effect when using cardios? If they are 1.7 farther, bass section will really sound thin and weak.

Once again, you're mis-applying the theory.

Yes, for a given direct/diffuse sound balance cardioids can be 1.7 times further from the source than omnis.

And yes, cardioids will exhibit proximity effect when close to the source... But by 'close to the source' we are usually talking within 10-30 centimetres.

If you're miking a choir the mics will inherently be at least a metre away from any individual voices , and probably several metres away -- so there will be no proximity effect whatsoever.

If your mics sound thin and weak when used in this 'distant-placement' way, you're using the wrong mics!

Some cardioid (or other directional pattern) mics are designed to give a flat low-frequency response when used very close to the source -- such as most stage vocal mics, for example. In these situations, the designer knows proximity effect will be present and so balances the mic to take that into account, with the benefit that the low-end from more distant sources will be greatly attenuated -- which is a very useful side-effect in the live-sound application. But if used in a distant-placement role, this kind of mic will sound very thin and weak...

What mics are you using at the moment? And if you're looking for a good cost-effective starting point with some versatility, I'd recommend the Rode NT55 stereo set which comes with both omni and cardioid capsules.

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Re: What mic technique is used in this recording?

Postby george_vel » Fri Mar 16, 2018 12:58 pm

I am using Oktava MK012 cardioids, purchased from Thomann, no modifications, guess Russian, but not Chinese edition.
In general, I am pleased with the mikes, but so far I did one recording in a small rehearsal hall with awful reverb and did not tested them yet in a better sounding venue. So I really cannot say how they will perform in the church I've mentioned earlier - this will be tested in a few pre-recording sessions when the time comes.

And yes, I want to add 2 more mikes to my collection, so I was thinking about exactly either Rode NT55, or Oktava MS4 version with Omni & Cardio capsules.

Thanks for your inputs, it's really valuable for me.
If I am following you correctly, I need to position the X/Y or ORTF main cardio pair as a first step, and then testing different positions with the omnis (either in line with the main pair; or farther / closer to the source; and more narrow or more wide, etc.) until I like what I hear.
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Re: What mic technique is used in this recording?

Postby Hugh Robjohns » Fri Mar 16, 2018 1:27 pm

Generally, the outriggers are in the same plane as the main pair, rather than significantly closer or farther away from the sources (to avoid timing problems).

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