Hi. So I will be running audio for a feature shoot in a few months, and I'm trying to get all of my ducks in a row in advance. After going through the script, I've identified a few locations which could be inherently problematic. First of all, we're shooting this on a 5d MkII, and audio is being captured on a Zoom H4n. I have two boom mics at my disposal (Rode NTG 3 is my primary, and an AT 8015 is my backup), and also have three Sennheiser G3 wireless lav systems if needed.
The first possible problem location is a church, in the sanctuary. Fortunately, the scenes here are mostly quiet dialogue between two actors positioned pretty close together, but I am concerned about excess reverb here. I'm thinking if I boom close with the Rode NTG 3 and put lavs on the talent, I should be ok here.
The other potential issue is a studio where we will be shooting some green screen stuff. The space is about 50' X 35', with an 18' ceiling. Concrete floor with thin carpet, one wall is brick, one is drywall, and two are corrugated metal (I know, I know!). As it is, the room is a nightmare for sound, but we will be building a set in that room which will be roughly 20' x 30', fully enclosed...a room within a room kind of deal. I'm thinking the Rode plus lavs as backup here would work as well, but I won't know how much of that reverb is going to affect this set until it is built. Does anyone have suggestions for either materials to include in the building of the set to keep the reverb of the larger area down, or for better microphone options for such reverb heavy rooms? I think if it came down to a hypercardioid being the only way, we could probably swing the budget for an Octava MK-012 hypercardioid, but obviously, if we can do this well without spending the money it would be better! Thanks alot for any insights here.

Two words: Moving Blankets.


You can pick them up at YouHaul, and hanf them around, or place them on hard floors. Especially in the green room. You must put those up on all the walls that aren't in the shot. Nothing takes you out of the green screen illusion more than echoy room sound.

Seriously, put them up everywhere.

Thanks for confirming my first line of attack, Chad! I don't know U-Haul's prices, but I checked with Uline...Moving Blankets, Moving Pads in Stock - ULINE (http://www.uline.com/BL_7900/Moving-Blankets) and they do $13 apiece for 24 or more quantity...I'll need that many! Nice thing is, I can charge that off to the production company, since its not technically "audio gear", and they'll probably let me keep them, because they won't know what to do with them...

They can be for "protecting and moving props." Dual purpose!

"Dual purpose"...I love it!

Andy, try Harbor Freight Tools for low-priced mover's blankets. They have stores all over.

Search results for: 'movers blanket' (http://www.harborfreight.com/catalogsearch/result?q=movers+blanket)

Ken

I've also heard that a large quantity of helium balloons floated to the ceiling can help damp down a lively room. Never tried it myself but I've read about it more than once on multiple forums.
Bernie

Thanks, Ken, for the Harbor Freight link. There's a store not far from me, and those are cheaper than Uline. As for the helium balloons, its and intriguing idea, but I'd hate to get all those balloons and have it turn out to not be helpful. Would make for an interesting story, though!

Andy, try Harbor Freight Tools for low-priced mover's blankets. They have stores all over.

Search results for: 'movers blanket' (http://www.harborfreight.com/catalogsearch/result?q=movers+blanket)

Ken

Can also try Movers Supplies' Producers Choice blankets (white/black with or without grommets):

Sound Blankets Producers Choice BW Sound Blanket Oversized Producer's Choice. 6 pack, BLACK Sound Blankets Producers (http://moverssupplies.com/index.php/cPath/55)

A more expensive option but actually NRC rated are something like Audimute's Absorption sheets.

Audimute Sound Absorption Sheets | Materials That Absorb Sound | Soundproofing Blankets - Audimute Soundproofing (http://www.audimutesoundproofing.com/audimute-sound-absorption-sheets-materials-that-absorb-sound-soundproofing-blankets.aspx)

I've wondered how those absorption sheets performed side by side against the much cheaper sound blankets....

It would be nice to know how fire prone these blankets are. You wouldn't necessarily need them to be fire retardant, but you wouldn't want them to flash burn (or give off toxic gas while shooting napalm-like splatter) when next to a hot light.

Unfortunately, I don't see fire resistance mentioned. You probably need to go to installation materials like Auralex before you'd see official ratings.

It might be a good idea to get a minimum order and do a quick, outdoor lighter test before buying a big lot of the stuff. Again, you don't need them to be fireproof, just well behaved around hot lamps.

I have considered flamability, but we will be hanging these things from the 18' ceiling well above the level of the lights, and also in a perimeter around the setup where they won't be near any lights. I will definitely give a little fire safety spiel each day we're on set, though. I can just add it to my "turn off you cell phones and if you're not on camera or in the active crew, sit down and shut up" spiel. Doing a test burn isn't a bad idea either, just so we know exactly what we're dealing with.

Yeah, fire is unlikely, but you don't want to contribute to the risk if you can avoid it.

A past boss of mine previously managed a research group at a large tech company. They had a nitrogen fire suppression system in one of their materials labs. One day they had a fire drill. A guy in the lab thought, "screw it. It's just a drill and I'm in the middle of an experiment." Even though it was a drill, the air in the lab was replaced with nitrogen and the guy suffocated. Needless to say, they changed their fire drill procedures and improved training - after the accident.

Stay safe out there!

That's a crazy story, Jon! I'll look around and see if there are any fire retardant treatments that can be done to the blankets after we get them...Something like Scotch-Guard, only fire retardant, not stain repelling...

fire retardant | flame retardant | fireproofing (http://www.natfire.com/)

Re flame retardant sprays etc. This is just one - google flame retardant sprays.

Thanks for the link, Jim. That stuff looks like the business for this kind of application. It's not cheap, but looks to be worth the money.

Would applying this substance to a black cotton backdrop increase the reflective quality?
Presently the black eats the light and has no reflections.

Depending on what type of mic your using, you may not have to sound proof the whole room. For instance, if you are using a shot gun mic, you may be able to get away with just outting th mic as close to the subject as you can, and just surround them and the mic with moving blankets. Kind of box them in.

Haven't tried it myself - the problem with this kind of stuff is that you never know if it works until it's too late - sort of like having a leaky lifeboat or a defective parachute I guess. And it's as they say say it's a retardant, not a preventer

Kevin, that was my plan exactly. I'll be running a Rode NTG 3 on this shoot, which is supposed to be delivered on Monday. Fortunately, I have two other shoots before this one to get used to the mic, as well as testing it out in the actual studio space when we hold auditions there in a few weeks.

If the NTG-3 still has a hollow echo sound, try renting a Sanken CS-3e. I tried one at NAB last year and then went straight to the Sennheiser booth to try the 416 (which seems to be the design target of the NTG-3) and the difference was amazing. The 416 had a constant boomy noise from the show floor while the CS-3e background was evenly suppressed with a fairly flat response. The difference was night and day.

http://www.dvinfo.net/forum/all-things-audio/477209-sanken-cs-3e-magic-mic.html

If you control the reverberation reasonably well and get the NTG-3 close to the talent, it should sound great. No need for an upgrade. But if the echo is boomy and problematic, check out the Sanken.

One difficulty is that the blankets will reduce the highs and mids, but it's the lows that can make the echo sound weird. To kill the lows, space the blankets from walls. If you have bookshelves on the set, pull them slightly from the walls. Pull the books toward the front of the shelf, leaving space behind, making poor man's bass traps.

Well, the NTG 3 IS my upgrade for this shoot! I'm getting more confident after learning more about the set that is going in the space. I will definitely not have blankets on the walls. They will be suspended around the set, well off the walls.

One thing I've learned over the years is that you can only "pre think" sound issues so far.

A good example was the construction of the control room of my studio. I not only built it with non-parallel walls and good isolation, I'd planned on lining the inner surfaces with reailliant channel and using Owens Corning 702 panels (which I scored from a decommissioned studio in my area) for both absorbtion and great isolation.

When phase 1 of construction was done - but before the install of the channel and 702 - I got an "emergency" gig and had to use it before completion. To my astonishment, the space sounded WONDERFUL already. So I sold the rest of the soun treatment stuff, and to this day, a decade later, I'm still using it "half finished.

The point is that The space didn't actually need what I "thought" it would need. It just needed what it needed.

Think, yes. Plan, yes. But don't ever be surprised if the answer is more OR LESS than you thought it would be.

FWIW.

Great point, Bill.

My guess is that the NTG-3 will do the trick - especially with the forethought in this project.