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Changing the room tone by rearranging sound blankets - good or bad?


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I'm currently learning the proper use of sound blankets and other absorbing material on set to deal with reflections. So far I tend to use quite a lot in most locations I get to, thinking that you can always add reverb in post, but not take away what's already there. When moving the camera I often have to remove some of the added blankets, carpets etc out of the frame, and put it somewhere else.

Now, I have not had much experience of dialogue editing, but what little I had taught me that very little is needed to change the sound of a room. I was wondering if maybe moving around absorbers this way might cause some trouble for sound editors, or if the added intelligibility is worth it? Should you perhaps only use sound absorbers in places where you know they won't need to be moved during the course of the scene? In the end, maybe it doesn't matter, since repositioning the mics, lamps and people etc has a far greater effect.

Also, If I may cut in another absorption-related question, does anyone have any good tip on practical materials used to clean up low end on set? Is compact, thick matresses the best bet?

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There's a balance between your trying to improve your sound and getting in the way of progress on set.

I try to "fix" a space if I believe the sound of the room does not match the "reality" of the scene, or if the reality of the space might be distracting to the audience.

I find I do very little in most instances. Others here do a great deal. It's really a matter of choice. And as we have discovered in another thread, with a little planning, it's possible to closely match a live room in the event some dialog needs to be added or replaced.

My vote is to record the space the way it should sound for the audience. Post won't always add the "room" into your recordings. As we are the ones on location, I believe the responsibility of capturing the performance live includes capturing where it was recorded.

Robert

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Room tones can shift dramatically, even without blankets in place. So recording several room tones for a scene shouldn't always be out of the question. Doing what you can to kill reverb in most situations will certainly earn you some praise from the post audio team. Overdoing it may not.

There is a recent thread here about Altiverb - and what convolution reverbs are capable of.

A couple things to think about: yes, getting clean, dead sounding dialog is generally good - but not if it seems incredibly unnatural. Getting the dialog for any given scene/location equal and even in this regard might be even better (IMO).

I personally go for a bit drier sound if possible.

But - as Robert mentioned - we are all generally running against the clock - so the last thing you really want to do is unnecessarily hold up production.

If I need to get a blanket down on the ground, my boom op and I are usually ready to go and do it quick - we don't wait for the grips.

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about the low end - Are you really finding yourself on sets where the frequency response is outrageous?

Practically speaking, I can't imagine bringing mattresses on a film shoot.

Yes - mattresses, couches, bigger padded furniture, will help tame the low end.

what might be best is to consider where it's coming from. Corners - or angles of 90 degrees or more - are generally where low frequency energy builds up. so sometimes a sound blanket folded over a couple times and placed to form the hypotenuse of the corner will help.

A simple solution is to add people to the room.

Actually - a somewhat lightweight solution would be some fiberglass panels. These can also be placed to straddle corners and are easy to prop up.

That said, I think many of us tend to do what we can with sound blankets. A resonating low frequency can often be tamed with some eq in post.

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Room tone might not have been the best term to use in this case - I ment both the silent background and the rooms reflective character. Sorry if it was unclear.

I hear what you say about not being in the way or holding up the production - It's something I always evaluate before I start to treat the room, and so far it's been working well. I also make shure to record several passes of atmosphere/room tone if I feel that something has changed in a not so subtle way - a door that must be open for a certain shot, several lamps that are added or removed etc. As I've said I don't have much experience in post yet, so I don't know to what degree I've done it too little or too much, or not covered the right angles - time will tell.

Regarding the low end - yes, I have been in situations where we've worked in near empty rooms with parallell walls, or big rooms that we only use a small part of, which just sound so very wrong. In those cases I've gone crazy with carpets, blankets, drapes and the like, and while it did get a whole lot better, I still felt it was a bit "boomy" from the lower frequencies they didn't quite cover. The result may have been good enough, but I would like to know what more could be done for future situations. It may also be that I could have used the materials better, placing some in corners, pleating blankets and so on, which I did not do.

I think I will experiment a bit using blankets piled up near corners, and add a matress or two to see the difference - I've heard it mentioned before that corners are a hot spot, but havn't really tried it out. Fiberglass sounds interesting too, and I've heard thin plywood would also be good. I don't think I'll have the time or material for such tests this year, but maybe in two months or so. If I do I can put the results up here, either as sine sweeps or just some voice tests. Remind me if I forget it!

Another related point of interest - how many of you sometimes record convolution reverbs on set for use in post? This is something that I can imagine would be very useful if it did not cause any problems on set.

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The director on my first feature gave me a great bit of advice (after tearing me a new one) that I pass on from time to time, "Be careful not to cause new problems in the course of solving yours."

Treating rooms during a busy production day can be a dicey business, depending on the coverage being attempted. First determine if there is an actual problem with the room before altering it needlessly. If there is a real issue, I put it on the AD's radar and anyone who may be affected before tossing stuff down. Having a proactive rapport with all departments makes our job WAY easier, you'll actually have people looking out for you.

I bought a box of the Owens Corning 703 fiberglass a while back. I wrapped some black burlap around them and they work nice if you can tote them around. Furni's end up being used most often, though, as they are always available.

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One thing that reduces reverberance in rooms and is very easy to do is opening windows. In most cases there is unwanted noise outside, but if there isn't, this is something I do and has improved the sound of dialogue by quite a bit in certain locations (such as a glass veranda). However, some people on the set will wonder what the hell you're doing as usually sound wants all windows to be closed because of noise sources from outside.

The only other thing I will do to reduce reverb is lay carpets where I can. Blankets or absorbers are usually in the way of light or others.

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If ever lighting dept want to put up flags or floppys or the likes of it, simply ask them if you can, pretty please, set up a blanket there instead. Does the job for them and for you. Make sure your blankets are black on one side and white on the other. That way you can even replace a reflector (frigga ;))

And choose your battles! If you start focusing on dampening a room when you have lots of people talking in a scene, might mean you lose the focus on laving properly or checking plant mic placements or boom shadows or whatever.

Guessing you're Swedish, your name certainly sounds like it, I know you probably do a lot of one man jobs. And in that situation I never ever dampen a room. It is the productions "fault" they hired one person. And if I have more than one channel to watch and do the booming, I'm not gonna do one hit of dampening if it isn't extremely simple or I have oceans of time on my hands prior to take. I've done oh so many one man gigs I don't even know where to begin.

My best tip is just go real close (get a cmit-5 u) and lav everyone, don't worry about room. If you're alone, don't bother. Production can do all the explaining to post.

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Hello Olle!

Yep, as the name indicates I am indeed swedish, and while I'm currently just a film student, I have done, and expect to do, quite a few one man jobs. I agree with you up to a point that there's sometimes no time to treat rooms, and that the production should then take the hit for choosing the location, but I know some production people just don't think of sound when looking for location, and doesn't have the knowledge to determine when something is too bad to handle. I like to do what I can to know I've done a good job, and if I at some point feel like the location is impossible, I simply tell the FAD and see what he/she decides. Either they give me some time to try and fix it, or I have to do extensive wild takes or ADR.

Thanks for the tip about replacing a reflector with a blanket - I've heard it mentioned before, and at some time I have to go buy the material and make a few. I was thinking about putting on a wooden ledge with a hanger of sorts so it can be put on a single stand, and then just be rolled up when not used.

"Be careful not to cause new problems in the course of solving yours."

This is good advice, as is being proactive with other departments. I'll try to think of this on the next production.

Christian: Thanks for the tip about windows - I had not thought of it as a possibility. I think the situations when it can be used is very limited, but it's always good to have one more trick up your sleeve.

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" capturing the performance live includes capturing where it was recorded. "

keeping in mind that unfortunately, the place it is recorded is not at all what the place in the story is supposed to be!

Yes, which is why I'll point out my original post preceded this colored quote with this sentence...

I try to 'fix' a space if I believe the sound of the room does not match the 'reality' of the scene.

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I was wondering if maybe moving around absorbers this way might cause some trouble for sound editors, or if the added intelligibility is worth it?

As a dialogue editor I like tracks to have as little noise as possible. Noise can be reflections, reverberations, footsteps, wind, traffic... anything that isn't dialogue. If the noise plays in the shot without overpowering the dialogue, that's okay, but still preferable to not have it in the production tracks. Unless it's a very unique sound I'd rather it be done in post. Record it wild if you think it might help the post process.

I've removed perfectly fine sounding "door closes" from production tracks because I know the SFX editor will drop in his own. This gives the re-recording mixer total control over the volume of the dialogue versus the door close. I will put the muted production door close in the PFX track, just to have it as an option.

In the end, maybe it doesn't matter, since repositioning the mics, lamps and people etc has a far greater effect.

I've found that even slight changes in mic or actor position can change the "tone" enough to make one not cut with the other. This is especially true when the room is noisy. This doesn't mean they can't be in the same edit, it just makes for a bit more work.

Mark O.

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Mark, thanks for your input. From what you say there is some merit to get as dry dialogue as possible, even if it may be unnaturally dry for that space. I always try to remove all sounds happening during the dialogue, even if it's something that plays in the scene. For instance, I often put down carpets and ask the actors to remove their shoes, tell them to avoid putting down cutlary too hard during dinner scenes etc.

As I see it, if you have a proper post production for the project, you should do what you can during the time given to make the dialogue as clean as possible, but if the time in post is short (as it often is on the kind of no-budget student films I currently do) then everything that can give the desired effect on set is usually good.

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From what you say there is some merit to get as dry dialogue as possible, even if it may be unnaturally dry for that space.

Unnaturally dry isn't a problem. Reverberant dialogue trailing into other dialogue, or dialogue that has varying amounts of reverb/reflections is a problem.

For instance, I often put down carpets and ask the actors to remove their shoes, tell them to avoid putting down cutlary too hard during dinner scenes etc.

It's definitely a good idea to use rugs or have actors remove footwear on noisy floors. Directors may not notice things like footsteps and flatware obscuring the dialogue during production, but they will hate it when they get into post. Experienced actors know better than to make a noise over their lines, but there's always something that tries to make our jobs harder.

In my experience it can be like pulling teeth to get production to provide rugs on $1-10M budget movies. If you can get them on low/no budget films you're doing pretty good. If you are providing them at your own expense, then you may be going beyond the call of duty.

Mark O.

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I have worked with a few actors that avoided interrupting or making any noise during others lines without me telling them, but it has never been a big deal to just ask them to be quiet when not speaking. So far I haven't had any real problems in that area.

I suspect you are referring to some special kind of carpet, because what I use is mostly simple rag rugs and similar available for 5-10 dollars in second hand stores. Getting a dozen or more for a project isn't a big deal, and I see it as an obvious part of the equipment cost alongside tape and similar (if production grunts, you can always tell them what that little investment might save in avoiding damaging floors with stands and lamps etc).

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I suspect you are referring to some special kind of carpet, because what I use is mostly simple rag rugs and similar available for 5-10 dollars in second hand stores.

The rugs I'm used to seeing are the more commercial type - low pile with a rubber backing. They lay flat, can be rolled up into a tube and have some weight to them. When we are working in a sensitive practical location, historic or wood floors or rugs/carpet, they cover the entire working areas with them.

Mark O.

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I second Mark on this. Rugs are great for exteriors and pretty good indoors. You just gotta tape the suckers down, and they're (or could be) thick as hell!

Rubber floor mats are greatness.

Another low budget solution for dampening, which I find to be pretty good, however somewhat impractical, are cardboard boxes! You can stack them high, they're light, you can pain't them and they fold. Impractical like how? You have to have like an army of them to actually make it work...

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The rugs I'm used to seeing are the more commercial type - low pile with a rubber backing

I think I know the type you're talking about, and yes that would make it a bit more expensive. I imagine rubber backs are good to make sure they don't slip or slide, which is a potential hazard indoors. I sometimes do as Olle says and tape them down, but I prefer not to as it's a bit time consuming and cumbersome to attach and remove them frequently.

Another low budget solution for dampening, which I find to be pretty good, however somewhat impractical, are cardboard boxes! You can stack them high, they're light, you can pain't them and they fold. Impractical like how? You have to have like an army of them to actually make it work...

I've actually been thinking to test cardboard, because of something that happened before our last shoot. At that time a lighting guy at my school decided to make a small handheld kino lamp to brighten up actors faces, much like a reflector. When he had put it all together he was thoughtful enough to ask me if I thought the noise from it would be a problem, since it was going to be quite close to the actors, and hence the boom. I thought it was a tad noisy and asked him if something could be done about it. He then made a small enclosing box of cardboard covered with black tape for the electronic parts of the lamp, and then continued to cover the whole lamp in it - he even made barn doors of cardboard! When he was done, that lamp was completely encased and pretty quiet, and I gave him a big thumbs up. When on set, we had more problems with lamps standing several yards away than that kino.

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