Any advice on how to kill an echo in a large room?

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Posted

Ok, so I'm still quite a newbie when it comes to sound so please excuse my question if it sounds silly. Does anyone have advice as to how to kill/tone down an echo in a large room. I'm helping a friend out tomorrow with a student gig of his and so we will be shooting in a large warehouse/studio type location (floor is concrete with high ceilings). I noticed a slight echo when I did some preliminary testing. I was wondering if there were any tips you guys may have that can help me out.

Any info is immensely appreciated.

Thanks,

MIke

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Posted

Sound blankets up top to act as a sort of "cloud". If there is a tegular tile system, remove alternating tiles and hand moving blankets down through the holes. thick high pile carpet with padding on ground. Gobos / baffles set up around the shooting area. You basically want to identify all of the first reflection points from the sound source to the microphone and block / trap / deflect that reflective energy. Since it is a large space, it would be impossible to treat the whole space, so we are looking at isolating a small important portion of the space (the shooting area) and treat just that.

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Posted

Hey Tom,

Thanks a bunch for the info. I will do my best to do what you say.

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Posted

Radios in bad environments can save the day sometimes, but rugs/blankets on the ground help some whatever way you mic it. A warm round mic like a schoeps can be used at times to your advantage. I would say never use a long mic in that environment. Try to control the noise makers that fill up a set before you start capturing sound n image. Sometimes the echo sells the shot. Good luck.

CrewC

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Posted

By "noise makers" in the shot, CrewC is referring to your fellow filmmakers. There is an advantage to having them on set however, the human body is a wonderful absorber of sound wave energy... If you can only get them to clam up and not produce their own!

Visiting a local carpet seller and asking if they have any remnant ends available is helpful too, I got a HUGE amount (More than enough to cover an entire set) of super-thick hotel carpet from a job they had done for less than $1 per square foot. This stuff was great for sound, it was rubber backed and about 3/4"-1" thick solid pile. Ugliest pattern I've ever seen... But who cares, right? :D

Good luck on your shoot

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Posted

Lavs or wide pattern boom mic, as suggested. In this case louder is not better. A close mic in a normal speaking voice.

I have used carpet below and a 4x flag overhead just over the mic (and any other flags they have to put around without blocking lights). Furniture pads hanging on stands, etc. Any fabric to break up the are around the actors. And people too will help, as mentioned, if they can stay quiet.

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Posted

What kind of boom mic are you using?. Stay away from a shotgun mic in these environments. Instead, use a super-cardioid or something similar.

-Richard

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Posted

I love working in reverberant rooms and spaces...the trick is to get much more of the direct sound than reverberation...whatever it takes.

BVS

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Posted

BVS has a good point above: in some cases, the reverb may be part of the story and add realism to the scene. I'm thinking of the scenes in Citizen Kane where Orson Welles had conversations in giant, cavernous rooms, and his voice thundered down the hallways. Keeping that consistent and listenable would still be a challenge.

But if you've got two actors trying to have a reasonable conversation, and the reverb is out of control, then you have to find ways to deal with it. A lot will depend on how the shot is covered. If you're on a wide shot, there's no place to hide the blankets and flags. Once you get in close, there's a lot more you can do in terms of enclosing the actor and minimizing the reflections. Have the grips bring in a lot of C-stands, and use those to hang sound blankets where needed. That saved me on a commercial shoot in a very bright, large tiled kitchen area about six months ago.

There is that famous trick of bringing in helium balloons to break up all the hard surfaces from the ceiling, but that may not be practical in this case. (And my apologies to the person who thought of this years ago -- it's a brilliant idea.)

--Marc W.

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Posted

Get the mic as close as possible and use only enough gain as necessary to get a usable signal. Try to drop the echos off the noise floor. If the actors are shouting then you'll have a much harder time.

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Posted

I love working in reverberant rooms and spaces...the trick is to get much more of the direct sound than reverberation...whatever it takes.

BVS

While working with an Oscar winning Sound Mixer, I had asked him how he handles rooms that are reverberant. He quickly replied with "Nothing! If the room is large, it should sound large." I was shocked by this response! I struggled and spent many hours trying to control these things, prior to asking this question. Now, after more experience, I couldn't agree more!

Perhaps this isn't the case in your situation. Perhaps you're shooting in a large space(warehouse), but it "looks" like a small place? Then all of the above statements are very valid. Mic choice and keeping that first reflection down is key, carpets being a necessity, especially with a mic pointing downward. The next set of reflections tend to get buried in the next line or next actors line of dialog. And if there isn't any dialog to cover up the second or, god forbid third reflections, get enough room tone for post to cover them up. I would also add that wrapping the sets in thick duvetene helps a lot also, if you have the budget. This method helps the grips also, by keeping outside, unwanted light from leaking into the set. Although, "student film" tells me this option is too expensive. Good Luck

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Posted

Large reverberant spaces defy control with anything less than large, and probably expensive, efforts. The volume of carpet, furniture pads, helium balloons, and other sound deadening material needed to take down reverberation in a train station is huge. A warehouse would require less but you would still need quite a lot to make an audible effect.

As others have said, the reverberant quality can add character to the recordings. But if several people talk at once, or if they deliver their lines with tight pacing, then the competing echos create a babble of noise. Simply having one actor pause a moment for the echo of the first actor's line to decay can help immensely to control an overly live space. This requires cooperation from the director. Talk with the director and ask if the scene can be staged to time performances so the echos don't overlap. Usually the pause needs to be only a moment, a second or so. One of the nice things about this approach is that it costs no money at all and requires no set up time.

It's good to tame the echo as best you can, consistent with not holding up production. The live quality is probably more of a presence in a monophonic recording than to your stereo ears on location. (But, no, a stereo recording is probably not part of your solution.) I've found that a section of carpet or a thick pad of a folded furniture blanket placed at the feet of the speaker can do more to tame echo than pads hung throughout a large room. Of course, if you've got twenty furniture pads and the stands to hang them, that's another matter.But I mean that one folded furniture pad can do more if the mike is aimed into it than two or three pads hung elsewhere. Your directional (not shotgun) microphone will pick up much of the echo bouncing from the hard floor. By padding the area immediately around the actor's feet you reduce this immediate bounce. You'll still get bounce from other sources but you'll reduce some of the "hottest" bounce.

David

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Posted

Is there any constant to where reflections will be "hottest"? Is it always the closest or "most" reflective surface, or those surfaces angled perpindicular/parallel to mic position?

And as hair quickly recedes from my forehead, is it appropriate to ask G&E to "duv" my newly "reflective" surface?

Best,

Steven

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Posted

As usual, excellent suggestion from Dave...

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Posted

I agree if you're in a large space, and you see the large space, then the echo can be ok - as long as it's not distracting. I always tell production, when asked if an echo is ok, "If we're in a bathroom and it sounds like a bathroom, then it's fine. If we're in a living room and it sounds like a bathroom, then it's not ok."

Also, on a wide shot, the audience will accept the echo along with the visual, but in a close-up it might not be what the director wants. Echo can be added. It can't be taken out. Also remember that in real life, our ears compensate and we can get used to the echo. In a theatre or on television, no such compensation exists.

But as David pointed out, the best choice is to carpet the area below the feet. I have also found a 4x flag above the mic to be very useful, more so than hanging pads.

Robert

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Posted

" "Nothing! If the room is large, it should sound large." "

I guess you are stuck with it, but it unless it is supposed to look and sound like a big space, I'd consider it a bad choice of location. I'd be real concerned that the friend you are "helping" is going to be disappointed in the results, and make sure they understand the issue falls under the laws of physics.

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Posted

" "Nothing! If the room is large, it should sound large." "

I guess you are stuck with it, but it unless it is supposed to look and sound like a big space, I'd consider it a bad choice of location.

Yes, and yes. All in the context of a part of a scene, and referring to BVS, and Mark Weilage's statements, not the original posters question.

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Posted

I said: " I'd consider it a bad choice of location. "

and I shall amplify: The OP described himself with the word "newby", and mentioned "student". project. A lot of times students shoot in really bad locations for their shoots, sometimes even because that is what the school has: highly inadequate shooting spaces. The sad thing is that instead of giving priority to creating better shooting spaces, these schools squander their finances by staying in the highly expensive camera flavor of the month game. The other thing is that students do not get taught professional set operations, the ones honed from over 100 years of making movies, and almost 100 years of making talking movies! These factors combined with lack of budget result in a number of issues, one of which is that their projects sound like "student movies".

In this case the OP has been on a scout and is alerted to the challenge, but has few real possibilities of implimenting many of the preferred solutions Extrapolating, he probably will not have a choice of microphone, but will have to use what is available, and most often in school kits that is the less desirable short shotgun type mic. The way students light (if at all), and shoot these days, proper booming is always a challenge, and having multiple open wireless in the echo chamber can often approach the boom sound for reverb s/n, plus adds all the things that go with hiding wireless on non-professional actors in wardrobe, including jewelry, they brought from home...

and in the end with all the other issues they have in these circumstances, some of the differences they can make end up getting buried in all the other issues. All that said (or typed!), it is encouraging to see Michael, the OP, concerned about the sound issues, and looking for ways to minimize them!

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Posted

I said: " I'd consider it a bad choice of location. "

and I shall amplify: The OP described himself with the word "newby", and mentioned "student". project. A lot of times students shoot in really bad locations for their shoots, sometimes even because that is what the school has: highly inadequate shooting spaces. The sad thing is that instead of giving priority to creating better shooting spaces, these schools squander their finances by staying in the highly expensive camera flavor of the month game. The other thing is that students do not get taught professional set operations, the ones honed from over 100 years of making movies, and almost 100 years of making talking movies! These factors combined with lack of budget result in a number of issues, one of which is that their projects sound like "student movies".

In this case the OP has been on a scout and is alerted to the challenge, but has few real possibilities of implimenting many of the preferred solutions Extrapolating, he probably will not have a choice of microphone, but will have to use what is available, and most often in school kits that is the less desirable short shotgun type mic. The way students light (if at all), and shoot these days, proper booming is always a challenge, and having multiple open wireless in the echo chamber can often approach the boom sound for reverb s/n, plus adds all the things that go with hiding wireless on non-professional actors in wardrobe, including jewelry, they brought from home...

and in the end with all the other issues they have in these circumstances, some of the differences they can make end up getting buried in all the other issues. All that said (or typed!), it is encouraging to see Michael, the OP, concerned about the sound issues, and looking for ways to minimize them!

I think you took that the wrong way, Senator. Still not sure how that is even possible. But I've misinterpreted threads before. I can only assume since you quoted me, that your first sentence was meant for me. No offense meant, my first yes was for, "I guess you are stuck with it", and the next one was for "I'd consider it a bad choice of location." Perhaps you thought I was questioning you or something. Either way, I'm still confused, and am just going to stop here. have a great day!

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Posted

Shoot a plate of the warehouse and do the dialog on green screen. There. Problem solved.

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Posted

Having been in this situation a few times, and sweated solutions, I think in future I'm not going to sweat it so much, so long as the picture similarly reflects 'big and reverberant' space.

One was a courthouse that with our 15-person scouting crew had me kinda quaking, but it was fine. I wired everybody preventatively, but the crew, background, gear, mic choice, etc., cut the reverb sufficiently so that the words were intelligible and properly judicially magisterial.

Same thing elsewhere once the crew got into the excruciatingly reverberant steel-walled, steel-ceilinged, cement-floored space. I had helium tanks and scads of balloons standing by that time, but didn't even bother. It sounded not one bit echoey on the day. Go figure.

Maybe I got lucky :)

-- Jan

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Posted

If you have a choice or the possibility, it is often better to treat surfaces that are non-facing--like two adjoining walls around a corner, or the ceiling but not the floor if your resources are limited, rather than treating two walls that face each other but not the other two. Also--corners are not your friend. In a reverberant space, anything you can pile up in it anywhere will help--compare your bathroom with and without towels!

phil p

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Posted

Having been in this situation a few times, and sweated solutions, I think in future I'm not going to sweat it so much, so long as the picture similarly reflects 'big and reverberant' space.

One was a courthouse that with our 15-person scouting crew had me kinda quaking, but it was fine. I wired everybody preventatively, but the crew, background, gear, mic choice, etc., cut the reverb sufficiently so that the words were intelligible and properly judicially magisterial.

Same thing elsewhere once the crew got into the excruciatingly reverberant steel-walled, steel-ceilinged, cement-floored space. I had helium tanks and scads of balloons standing by that time, but didn't even bother. It sounded not one bit echoey on the day. Go figure.

Maybe I got lucky :)

-- Jan

lol, use the balloons anyway. They will all think you are a genius. Never hurts when they all think that.

Billy

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Posted

Just had a thought....lol...

If as Jan said the crew all soaked up the reverberation so much...none of the crew were stuck to the walls to cut it down, then it probably doesn't matter too much where in the space you place your absorbent material as the 2nd and 3rd reflections will pass into them at some stage.

So on that basis can I suggest that you buy some small polystyrene balls in plastic bags and empty them into some soft material sacks and place them around the area, out of shot. The balls come as packing material for many things and are cheap to buy from a plastic stockist and are totally reusable. They are light and can be manoeuvred into any handy spot...an absorbent trap.

BVS

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Posted

How about we stimulate the economy and just hire people to stand quietly in the room!

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