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Acoustic screen behind mic against a wall? Condenser Microphones
Old 2 weeks ago
  #1
Gear Addict
 

Acoustic screen behind mic against a wall?

The title might be a bit cryptic, but here is the situation.

Early November we will have a concert with a somewhat different setup from usual. The room is a box, 15m x 12m and about 5.5m high. As currently planned the band (community wind band) will be sitting against one of the short walls with a large projection screen above. At the other end against the other short wall will be the audience in three tiers (floor, 30cm, 60cm). A large projector ("beamer") will be hanging roughly above the audience from the ceiling (securely, I hope).

I have been trying to figure out how best to record this.

1) Hanging mics above the band from the ceiling might be possible, but would probably require more XLR cable than available. As well as be logistically a bit complicated.

2) Hanging mics above the audience is easier logistically, but that would put the mics close to the beamer. Those things are noisy and have air currents around them with cooling fans and all that, so not ideal. I intend to do a mid/side with the side being one of my AT4081 ribbons, so....

In both cases of a hanging mic the fact that my preferred mid mic is a T12 powered Sennheiser. The Tüchel cabling and necessary adapters would complicate a hanging arrangement further.

3) Putting a stand somewhere directly behind the conductor would probably have people tripping over it, and the mics and mic stand would probably cast a shadow on the screen.

4) Mic stand in the middle of the band (I have done that with some success in the past) would probably be safe, but again it would cast a shadow on the screen.

5) A mic stand at the rear of the room, against the rear wall. That would probably put the stand on top of the top tier (60cm high), requiring very good shock mounts. My Rycote would be tested to the limit. Also, placing a mic with its back against a wall is not a good idea on account of reflections. The mid mic will probably end up being an MKH416 which might have a rear lobe.

Here is the question: In situation 5, would placing one of the acoustic screens used behind a singer's mic behind my mid/side combination alleviate the rear wall issues? Important factor would of course be to ensure that the side panels don't get in the way of the side mic. I am considering this one:

TM-AR1 | OVERVIEW | TASCAM

Not that expensive and collapsible. Not sure if the side panels can be hinged outward to be flatter so as to not block the side mic. It probably isn't designed to do that, but when did that ever stop us, right?

Regards, Christine
Old 2 weeks ago
  #2
Lives for gear
Perhaps a less compromised stand position might be a pair of stands, either side of the conductor with either wide cardioids, cardioids or Omni depending on how live the room is with band and audience present

. In effect they would be in the middle of each half of the band, or in the typical outrigger position if you were running a Decca Tree. What you might expect would be lack of centre of band coverage, and you might overcome this with a boom arm on each stand bringing the mics closer to the centre, actually a wide AB array.

It's not ideal, but if you have control over height, width spacing and mic pattern you should be able to minimise the compromises ? Of course the mics should avoid casting a shadow between projector and screen. Cardioid type patterns should minimise audience noise and rear wall reflections, but may be too close to the front row of players...so experiment with height and rotate the boom arms to help.

Your option 5 may give the best overall blend of the band, but at the distance and height necessary (even with screen behind) you may find the recording lacks presence and focus and sounds a bit too 'roomy'.
Old 2 weeks ago
  #3
Gear Addict
 

Thanks for your thoughts, I hadn't considered the dual stands as you described them. I will give that some thought. At the moment I can't quite visualize how high I will be able to raise the stands before interfering with the picture.

Option 5 is basically a variation of what I have been doing in the recent past. I agree that with a standard cardioid it sounds too distant and roomy. But in my experience using a Sennheiser MKH416 (or MKH816 in an extreme case) as the mid mic makes a big difference.

There will be a dress rehearsal a week before, so I will have a little time to experiment and adapt.

Regards, Christine
Old 2 weeks ago
  #4
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Quote:
Originally Posted by connloyalist View Post
Thanks for your thoughts, I hadn't considered the dual stands as you described them. I will give that some thought. At the moment I can't quite visualize how high I will be able to raise the stands before interfering with the picture.

Option 5 is basically a variation of what I have been doing in the recent past. I agree that with a standard cardioid it sounds too distant and roomy. But in my experience using a Sennheiser MKH416 (or MKH816 in an extreme case) as the mid mic makes a big difference.

There will be a dress rehearsal a week before, so I will have a little time to experiment and adapt.

Regards, Christine
The main reason for recommending the dual stands plus boom arms is to get the mics/stands out of the projector's beam...hopefully they can be adjusted to be just outside the left and right right frame edges of the projected image.

Your supercardioid Sennheiser's could well make M/S workable at the rear wall distance, particularly if it's worked before.

You may even want to swing the boom arms backward (toward the audience) and then angle the mics downward, which would get you a little more distance from the front row of players. Hopefully one or more of these methods will prove viable in your dress rehearsal !

Edit: here's a 'backwards leaning MS pair' pic from Rolo 46 (Roger) to give an idea of what could work for a pair of outrigger-type mic stands, either side of the conductor
Attached Thumbnails
Acoustic screen behind mic against a wall?-rolo-46-ms-pic.jpg  

Last edited by studer58; 2 weeks ago at 02:46 PM.. Reason: add photo
Old 2 weeks ago
  #5
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Thomas W. Bethe's Avatar
I recorded the Canton Symphony Orchestra who were using three screens above the orchestra and three projectors in the audience for one of their concerts. I used two pairs of microphone (X-Y setup XY Stereo) in positions they would not cast shadows on the screens. Worked well. FWIW
Old 2 weeks ago
  #6
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Simmosonic's Avatar
 

Quote:
Originally Posted by connloyalist View Post
Here is the question: In situation 5, would placing one of the acoustic screens used behind a singer's mic behind my mid/side combination alleviate the rear wall issues? Important factor would of course be to ensure that the side panels don't get in the way of the side mic.
In answer to your question, I’m assuming it would work within the range of frequencies the screen is designed to block.

If you had the right mics at your disposal, a pair of forward facing bidirectionals (Faulkner style) would be your best bet for situation 5. In fact, Tony Faulkner describes that same approach when recording in a very reverberant environment - a pair of forward facing bidirectionals with baffles behind them. You can read about in my interview with him, here:

Stereo Masterclass

If I got your dimensions right, it means you would be recording a community wind ensemble that is placed at one end of a 15m long room, with your mics at the other end. The total distance won’t be 15m due to the depth of the ensemble, but it’s safe to say you’re looking at a distance of at least 12m, which is a long way. If you want to pursue that approach you might even want to consider shotgun mics with baffles behind/beside them. If I’ve got it right, the room would be 12m wide and about 5.5m high, so reflections off the side walls and ceiling might be a problem - another reason for going very directional...

Also worth noting that if you’re above/behind the audience you’re going to get a lot of audience noise - phones taking pics, people shuffling in their seats, children who don’t understand the need to be quiet, even just normal breathing - that may be louder at the microphones than the wind ensemble. And finally, projectors are rarely silent; most have a fan or similar for keeping them cool and that’s going to be making a hum in the room’s reverberation while also being directly in the path from the mics to the musicians, and closer to the mics than the musicians. Possibly can be filtered or removed with Rx.

I would consider this approach as a last resort. It has many practical benefits, but I’m not sure you’d leave with anything better than a document of the event for the musicians’ reference. Also, any coincident pair at that distance is going to capture a very mono sound image, and no amount of MS widening is going to change that. You might be better off with two bidirectionals or shotguns, with baffles behind each of them, and space them as required to get some semblance of stereo...
Old 2 weeks ago
  #7
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Quote:
Originally Posted by Simmosonic View Post
In answer to your question, I’m assuming it would work within the range of frequencies the screen is designed to block.

If you had the right mics at your disposal, a pair of forward facing bidirectionals (Faulkner style) would be your best bet for situation 5. In fact, Tony Faulkner describes that same approach when recording in a very reverberant environment - a pair of forward facing bidirectionals with baffles behind them. You can read about in my interview with him, here:

Stereo Masterclass

If I got your dimensions right, it means you would be recording a community wind ensemble that is placed at one end of a 15m long room, with your mics at the other end. The total distance won’t be 15m due to the depth of the ensemble, but it’s safe to say you’re looking at a distance of at least 12m, which is a long way. If you want to pursue that approach you might even want to consider shotgun mics with baffles behind/beside them. If I’ve got it right, the room would be 12m wide and about 5.5m high, so reflections off the side walls and ceiling might be a problem - another reason for going very directional...

Also worth noting that if you’re above/behind the audience you’re going to get a lot of audience noise - phones taking pics, people shuffling in their seats, children who don’t understand the need to be quiet, even just normal breathing - that may be louder at the microphones than the wind ensemble. And finally, projectors are rarely silent; most have a fan or similar for keeping them cool and that’s going to be making a hum in the room’s reverberation while also being directly in the path from the mics to the musicians, and closer to the mics than the musicians. Possibly can be filtered or removed with Rx.

I would consider this approach as a last resort. It has many practical benefits, but I’m not sure you’d leave with anything better than a document of the event for the musicians’ reference. Also, any coincident pair at that distance is going to capture a very mono sound image, and no amount of MS widening is going to change that. You might be better off with two bidirectionals or shotguns, with baffles behind each of them, and space them as required to get some semblance of stereo...
Good points. I do own two Sennheiser MKH816's and also a pair of AT4081 ribbons. I have experimented with that in the past. It works decently well. The AT4081's work better close up (or as a mid mic). The 816, as I think is common with long shotgun mics, has some off-axis coloration. Most recently I have been using a Sennheiser MKH416 with AT4081 in a mid-side configuration from about 7 to 8 meters away with very decent results.

Since it looks like we will be doing a rehearsal with mostly the same setup a week before hand I could set up a whole bunch of mics and see which combo works best. My Zoom F8 has 8 channels so plenty of space.

In my usual configuration I am also behind the audience. Height and directionality solves that. But in this case that will put me closer to the projector.

And yes, staying as far away from the projector is important. I do use RX4 if required, but prefer to avoid needing it.

Regards, Christine
Old 2 weeks ago
  #8
Lives for gear
Tony Faulkner explains the genesis of his 4 mic phased array, in this video, from 32:20 to 33:25....but before he placed them on a single bar.

What he explains is somewhat the same as I'm proposing...with the mic spacing contingent on avoiding the projected image left/right side frames...and omitting the omni mics.

YouTube

Maybe CM3 or similar cardioid/sub-cardioids would work ok at the spacing necessary ? Also, probably avoiding the angling altogether and point them directly to the mid or back rows of the band (depending on stand height)
Old 2 weeks ago
  #9
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Simmosonic's Avatar
 

Quote:
Originally Posted by connloyalist View Post
Since it looks like we will be doing a rehearsal with mostly the same setup a week before hand I could set up a whole bunch of mics and see which combo works best. My Zoom F8 has 8 channels so plenty of space.
That’s going to be very helpful!
Old 2 weeks ago
  #10
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jnorman's Avatar
Studer and Tom both have good suggestions. I would probably do a curtain array of 3 wide cardioids.
Old 1 week ago
  #11
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Christine, maybe a 'mic bridge support' like avillalta has pictured in posting #6 here could help to get your mics out of the way of the projector: Concert in church - but no centre mics....

Or, maybe it would put the horizontal bar directly in the path of the projection beam....only you can know the answer to that.... but it presents an alternative method to those already offered here (and gets your mics away from the projector noise )
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