Minimizing echo from domed ceiling

[doctabu]

Hey there,

I'm planning on shooting a documentary in about a year, so pre-production is just starting up.

I'm filming some high school students in a very particular class, while they're in it and while they're not. The thing is, when they're in class, their classroom is a room that's relatively large-- with the big downfall being the ceiling.

Essentially, imagine a large, square room-- about 40 ft by 40 ft. It's about... maybe 15 feet tall. Then, in the center of the ceiling, there's a 15ft diameter dome protruding above the ceiling and has windows out onto the roof.

What this does is make some terrible echoing occur in the room. Sometimes you can be somewhere on the other side of the room and hear something someone's whispering on the other side. This, I believe, will be a huge pain in the ass if I want to film something there.

However, I could be wrong-- maybe the echo wouldn't be picked up on something like a shotgun mic, but my guess is that this isn't the case.

Anyway, I was trying to figure out how I could possibly minimize the echoing issue. I was thinking maybe I could get some sort of baffling material to put on the dome by accessing the windows in the dome and somehow attaching it within. Otherwise maybe I could just block off the dome entirely with a sheet of something.

The issue with the latter idea is that, of course, it probably will look crappy and my guess is that the ceiling will come into the shot at least a couple times throughout filming.

Anybody have any bright ideas for such an issue? Thanks!

 

[SonicStates]

How big are the windows?
Does your location have a noisy exterior?
To alleviate some of the echo/reverb you are getting (and again depending on the location exterior and size of windows) you might consider having the windows open while shooting. The sound waves will have less places to bounce off and give you a headache.
Also, depending on what your set requires, more props are better in these cases (sound wise). Diffusion and absorption is key for making it sound ok. Hard surfaces are not going to be your friends but I suspect your are going to have plenty of them in a classroom.
In the end however, you are in a square room and square rooms are bad news for standing waves etc.
Can you get in the space and do some tests. Rearrange the furniture, bring stuff in, take stuff out, open the windows (unless they are just skylights of course). Take your sound gear and run some dialogue tests. Maybe you can scout another room while you're there.
Just some ideas. Hope they help or at least give rise to some other ideas.
Cheers,
Sam.

 

[doctabu]

How big are the windows?
Does your location have a noisy exterior?

The windows are small... half circles that are about a 2 feet wide and a foot tall.

The location (the school) doesn't have much of a noisy exterior on the roof (or so I'd hope).

To alleviate some of the echo/reverb you are getting (and again depending on the location exterior and size of windows) you might consider having the windows open while shooting. The sound waves will have less places to bounce off and give you a headache.

The immediate worry I have here is the cold outside. It's going to be shot in the fall in Milwaukee, WI, where the weather gets a bit on the brisk side at that time of year.

Also, depending on what your set requires, more props are better in these cases (sound wise). Diffusion and absorption is key for making it sound ok. Hard surfaces are not going to be your friends but I suspect your are going to have plenty of them in a classroom.
In the end however, you are in a square room and square rooms are bad news for standing waves etc.
Can you get in the space and do some tests. Rearrange the furniture, bring stuff in, take stuff out, open the windows (unless they are just skylights of course). Take your sound gear and run some dialogue tests. Maybe you can scout another room while you're there.
Just some ideas. Hope they help or at least give rise to some other ideas.
Cheers,
Sam.

Thanks for the help. I'll keep this all in mind.

Also, I might as well ask-- What's a good mic to use for such a documentary? I've been eyeing the Sennheiser ME66. Any thoughts on that?

Thanks again!

 

[SonicStates]

Hmmm, best to test that room if possible and use a heater (quiet) if having the windows open helps at all.
Regarding mic selection, something with lots of off-axis rejection. I haven't worked with the ME66 so can't comment from experience, but my favourite mic for this kind of situation is a Sanken CS-3e. It's probably around $1300 in the US (maybe).
I think, from what I have heard, the ME66 will get you there if that is at a better price point. Check out what Rode have to offer too.
Also, just as an expansion on the "diffusion" point, if you can get some of those dividers (that all staff rooms have) and arrange them at different angles to break up your square room, it might help...of course, depending on your scene requirements...
Goodluck!
Sam.

 

[ptalsky]

This may be a situation where lav's may be a good option for you. Lav up your leads and run multi-track. But, first and foremost, I agree with the person above that said to take your equipment in and test it out.

Also, since it's a documentary, look at establishing the dome early, and live with it - if you're trying to show what your kids experience in class, the echo is a part of it. It is the natural sound in the classroom.

Phil

 

[Tim Joy]

Furniture pads are your friend! A couple key locations might do the trick, but obviously you want to keep them out of the shot. I would NOT open windows and add more noise.

It also depends on how many people are in there and how close you are getting their dialog. If you can be a few feet away in a CU/ med shot, then I would think that an Me66 would work just fine. But, if it's a whole group and you are in a wide shot, it would probably sound like everyone is in a cave.

Since you have so much lead-time, why not asking if they can put up some attractive sound absorption on the walls? Sounds like they need it anyway.

 

[Oleg 2]

hang a net over the class room , fill the uper side with wite baloons , you will need ccople of handreds , moove the baloons from the centere if you use the light which comes from the op , if you dont , dont bother ,]\
for eacy placing the baloons , you can use helium ones , to take them up , but you will need net anyway if you shooting there for more thwen 1 day as they would start loosing the helium and go down .
if you place net , you also can use cheap matrasses for pool , it make the same as baloons but you cover much grater aria with less ,
nothing else will work , dont bother with spesial mics and all the blabla about hypercardioids