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what's your workflow for acoustically treating rooms for production?


mikebarber

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in the quest to get the best dialog recording i can get, i'm trying to learn how to reduce those pesky early reflections. i'm a fairly new sound recordist and thus far most of my gigs have been in boxy rooms with nothing but hard surfaces to reflect. i'm using a super-cardioid mic (sennheiser mkh-50) and getting the best/closest on-axis recording i can, and my recordings sound very good, but they can be better by getting rid of those early reflections still being picked up.

 

i'm thinking about getting some proper sound blankets (those 'producers choice' are what i'm leaning towards) and reading up about room treatments but these are focused on home theatre situations which are not the same considerations for production (totally different 'listening positions', etc). so i am wondering what the experience pros here do when they're in a situation like shooting interiors on location. you can't just blanket every wall, you have to be judicious with where you put sound blankets... what's informing your decisions on where to place things? 

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Judicious w/ furniture pads, yes.  Having "black-white" sided pads is a huge plus if you want to use them anywhere near talent or the camera--it is an astute political move to be able to ask the DP if they prefer white or black on the floor or a wall on the set (with the implication that you intend it to be one or the other, ie not "none").    Many pads that might be available from the grip dept are the standard blue-colored type, these are not what a soundie should invest in.  On smaller urban shoots these days with very reduced G+E packages I'm finding that I can't really count on G+E for anything--they just don't have room in their down-sized vehicles and carts for anything extra, so I need to bring my own stands and furni pads.   As far as placement: what ever you can get away with.  Especially hard walls facing windows, big hard table tops, hard floors, acute-angled corners near talent.  With so many shoots, even small ones, using mutliple cameras there are a lot fewer places to put a furni pad that is both not in a shot and doing you any good.

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7 minutes ago, Philip Perkins said:

it is an astute political move to be able to ask the DP if they prefer white or black on the floor or a wall on the set (with the implication that you intend it to be one or the other, ie not "none")

 

that advice is gold! definitely going to adopt that one. 

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It really depends... the following is based off of personal experience and will be different for other productions. 

 

First, make friends with the grips. They usually, not always, see above from Philip, have lots of sound absorbing things. The smaller the shoot the more you’ll have to rely on your own equipment and setup. Thicker, black and white or even gray furni pads are an excellent way combined with stands. This works best for smaller spaces just because furni pads are smaller. 

 

In larger spaces, we work with the grips to see if we can get 12x blacks to help calm spaces. This seems to help in gyms or larger rooms. As stated it is getting harder with multiple cameras. 

 

I will also say that the most important thing is listening to what the dialogue sounds like naturally in the space with a good boom op and proper mic choice. I’m always surprised to hear scenes after it’s been posted and aired. Scenes/locations that I hated or didn’t think sounded very good have cleaned up really well and didn’t bother me after hearing it air. I personally believe that people are becoming to accustomed to the sound of wires and we are loosing the natural acoustics of what rooms should sound like even on tight close ups. 

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1 hour ago, ryanpeds said:

Scenes/locations that I hated or didn’t think sounded very good have cleaned up really well and didn’t bother me after hearing it air.

 

i've had that experience too. even listening back to my recording in a quiet space afterwards and being surprised how much actually got rejected by the mic afterall, but sometimes i wish some of those reflections were attenuated a bit more. not totally eliminated, just more in the background, this is usually when it's a particularly wide shot so i couldn't get as close as i'd like.

 

i noticed both you and philip said "furni pads" rather than "sound blanket", does that mean you find the cheaper furniture pads you can get at home depot do an adequate job?

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To better answer your inquiry, I would be interested to know what kind of work you are doing. Is it primarily dramatic fiction or relatively static interviews?

 

With dramatic fiction it can be very difficult - not impossible, but challenging - to make any effective acoustic treatments. Characters move about in the room and sound absorbing materials that had been neatly tucked away can suddenly be visible. I've sometimes had some benefit from rolling up blankets and putting rolls in corners. To avoid marring walls with tape, you might have to use a C-stand and gobo arm to hold a blanket roll in the corner. I'm not an acoustic expert - and much of the science seems to have a voodoo element anyway - but I understand that padding corners can introduce a break in reverberations.

 

Interviews can be simpler. I've had good experience with folding furniture/sound blankets to a convenient size and dropping them at the feet of a seated interview subject. The thick pad stops reflections bouncing up from the floor. Using a directional (cardioid or hypercardiod) microphone will somewhat diminish reflections from walls and ceiling. But the directional microphone can't help picking up sounds that bounce from multiple surfaces and reflect back into the microphone from the floor. The pad at the subject's feet significantly reduces those secondary reflections. It's a simple plan to execute and it is more effective than one might expect from such a small effort. It's also unlikely to interfere with the camera department.

 

David

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it's primarily dramatic fiction that i've been working on. typically low budget, using a friend of the producer's house or condo as location... so not a controlled studio environment. i just thumbed thru jay rose's book producing great sound for film & video, which has lots of useful information in chapter 6 (well, the WHOLE BOOK is full of useful information, but you know what i mean). and what i take from that is, all things considered, my primary concern would be any walls/surfaces directly opposite the talent and walls/surfaces parallel to the talent would be my next priority for absorbing the earliest reflections.

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If your G+E has a truck's worth of gear at their disposal then asking for a "big black" etc to be put up to calm a space down is ok as long as you understand that you may be refused for many reasons.  Having your own pads is a really good idea (yes, I call them "furniture pads" because that's what they are).  If you have access to a location before a shoot (like a on a scout) you have a better opportunity to negotiate for what you need.  If you have the crew and the vehicle to bring them, fabric coated rubber mats are great for calming down footsteps and softening floors.  Some of the mixers I worked for back in the day had a stock of 3' x or 4' x 4' plywood pieces with egg-crate acoustifoam glued to them--used to block noisy dimmers, HMI ballasts, hazers etc..   But the basic building block of any location acoustic treatment is the furni pad.

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The producers choice black/white are worth it.  2 of them fit perfectly on a 12 by t- bar which can be hung on a single stand (I recommended two sand bags).  I usually try to negotiate with the grips to supply the stand and bar, offering to set/move/manage it myself.  It's not always successful, but when it pans out it can be really worth it.

I also carry rubber backed carpets for foot steps, and for under / around an interviewees chair.  I'm not a fan of blankets on the ground because they are slippery, but if noone is walking on them they help.

I often want to get blankets up and can't make it happen for many different reasons, but when the room warrants it and I'm able to get them up it makes all the unsuccessful attempts worth it.

 

 

 

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