Room echo

C

ColorBalance

Active member
I am using a shotgun mic (NTG-3). Room echo is always a problem; one way to remove it is by covering bare walls / floor with blankets. Three questions I have in this regard.

1. It is not always easy to do wall-to-wall coverage. Where should one focus the most? Ceiling? Front wall (behind the mic), wall facing the mic?

2. Will something like a bed-sheet do the job as opposed to a blanket?

3. Is it better to put the blankets on the wall, or surround the actor by them (like creating a mini-room, assuming, of course that the camera won't see any).
 
1. - Knock down parallel walls first.
-Put the blanets on a non parallel angle to the wall slightly.
-The sides are pretty much the only area you're going to come in from without affecting lighting (most of the time).
-Dont forget the floors, easist place to put sound blankets and very effective for hard floors or footsteps.

2. The thicker the better. A bedsheet will do nothing for you.

3. as close to the subject/mic as possible
 
It is very difficult to do what you are describing effectively. Yes, hanging heavy drapes and laying down carpet or moving pads will help with echo, but not as much as many people think. Rooms are big, and require a lot of that type of thing to make much of a difference. If the room is that bad, I would see about a better location, one without parallel walls and better sound absorption. If you have to shoot there, the best thing is Rippie's third point, get the mic as close as possible. It won't hurt to lay blankets, but getting the mic close will do far more.
 
I am shooting in a big (empty) bedroom. One side is all glass windows with wooden blinds. Other walls are broken by many doors going to the bathroom, hallway, closets, etc. Ceiling is 12 ft high. Floor is wooden.

Based on your suggestions, I am assuming it is better to have all the doors open as sound will go out of the door instead of bouncing back. During most of the dialogues, I will be taking mid-shots, so I believe I should bring the blankets close to the acotrs (and make them non-parallel). I am also assumig that the 2" wood blinds will not reflect the sound much, and so no need to cover them with blankets.

The problem is, echo doesn't sound that bad on home TV's. Only when you play in theaters that you discover it, and by that time, it is too late. I wish if I could do some experiments, but guess not.
 
ADR is used for many echo situations. The time spent fixing a room and getting a clean shot for the camera is exten$ive. ADR works wonders.
 
If we are going to go beyond discussing "sound blankets"
let me just say, in an echoey room situation don't use shotgun style mic's.
Go for a hyper cardioid. The way a shotgun picks up sound from its sides = bad in tight rooms or live rooms.

I totally disagree with the statement above mine saying its not worth it to deaden the room,
and to just ADR it.
First off, while the lighting dept is working, what should the sound dept do?
Sit on our thumbs saying "lets just ADR it"?

2nd, a few blankets in KEY positions WILL improve your sound, you just need to know
where to put them in a given situation and hopefully get some cooporation from other dept's.

When you have the correct mic up, play it from a few different angles.
Perhaps coming from under (with bodies blocking some reflections) would be better,
or coming in from a particular angle putting "some" reflections in the null...etc..etc.

Every situation is different.
 
Totally disagree about ADR too. Try to control the acoustics as much as you can. Your goal is to make the room as small as possible with not parallel walls.. and YES change your microphone. A wider pattern, closer to the actors will work better than the shotgun.
 
I very strongly believed in ADR once upon a time, but after doing some experiments, I've realized that you can't just reproduce the chemistry, the emotions, and the mood of the original scene, especially when the actors aren't properly trained to do ADRs.

Obviously, I have to rely on it when doing outdoor scenes or if the room becomes very unfriendly (echo-wise).

Being a low-production outfit, unfortunately don't have access to a variety of mics and a whole bunch of "trained" crew.
 
ColorBalance said:
...
The problem is, echo doesn't sound that bad on home TV's. Only when you play in theaters that you discover it, and by that time, it is too late. I wish if I could do some experiments, but guess not.

....

Being a low-production outfit, unfortunately don't have access to a variety of mics and a whole bunch of "trained" crew.
Click to expand...

And that is why you need to edit in a room that has been treated for acoustics on real studio monitors on a properly calibrated system where you can listen at theatrical levels (85dBSPL), not computer "multimedia speakers" no matter how good they are.

You don't need a whole cabinet of mics but having the right tool for the job at hand is still necessary. Those room echos are the reason for the rule-of-thumb of hypers indoors, shotguns out. Add a moderatly priced hyper such as the Audio Technica 4053a or similar to your kit for those interiors.
 
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Any mic that can overpower reflections due to proximity is helpful. Once again, ADR, while painful for newbies, is often used for professional productions when the recording environment is not favorable.
 
WAIT A MINUTE!!

Sound blankets do work. They do not need to be set non-parallel. Sheets work but not as well. Last year I hung muslin backdrop for shooting video in my audio studio. It definitely changed the acoustics of the room. Hang what you can as close to the talent as you can, just out of frame. Don't forget the floor. Adjusting the blinds so they angle the sound a bit can help.

You don't want a shotgun, you want a hypercardioid in a tighter pattern, NOT a looser pattern.

In some cases, lavs will work better if you can't get a hyper close enough. I go over a lot of this and more in my little book. http://home.comcast.net/~tyreeford/AudioBootcamp.html

Regards,

Ty Ford
 
I've used DIY frames with stands made from pvc, drape sheets over them and "boxed in" the talent. The sound is absorbed by the sheets and no echo. Now this will only work for shots that you don't need the entire room for the scene. ex/ close ups, med shots. If you are doing an establishment shot with dialog I don't know what to tell you.
 
Just got a bunch of PVC pipes to make frames.

I guess I have to be intelligent in shooting. Minimize dialogues during establishing shots, and surround the actors via blankets during close ups.

I am pretty sure you have to choose your blanket colors carefully or the colors will bleed onto the actors. Got 2 9x12 paper-type floor covering to cover the blankets to avoid the color issue, and use them as reflectors (side benefit). Assumption here is that thin paper will not reflect audio. Is this assumption correct?

How about the ceiling? If the floor has a good carpet, does one have to cover the ceiling too?

I wish if I could get one more mic like the at4053a, bit can't afford it even if it is for $500 (spent $700 on the 1st one a few weeks back).
 
Yes Lavs will help a lot BUT they will sound like lavs. As a post person I will say flat out that ADR is easier to do and will sound better now than ever before (for low budget films). And I would never recommend it unless there is no other choice. Shotguns are bad news indoors, most of the time. There is usually no reason to assume ADR in the outdoors. City traffic can be a problem but not usually if your not VERY close to a street. I've done production and or post on a number of no-budget films shot in and outdoors that had little or no ADR. Usually ADR was required because of mistakes by production not because the situation was unrecordable. Usually you don't need lots of echo abatement but you do need to check the space out BEFORE the day of the shoot and you do have to listen to your sound person when they tell you that the take had problems.
 
ty,
i pretty much said all that.

But next time you throw up sound blankets try putting them a few degrees off parallel it helps believe it or not.
Im not talking 45degrees im talking 10-15.

Personally (read:my opinion) I wouldnt waste my time with sheets. way too thin to get any mid range or lower register knocked down.
Now of course if you fold them over 4-5 times..then you might be in business.


tyreeford said:
WAIT A MINUTE!!

Sound blankets do work. They do not need to be set non-parallel. Sheets work but not as well. Last year I hung muslin backdrop for shooting video in my audio studio. It definitely changed the acoustics of the room. Hang what you can as close to the talent as you can, just out of frame. Don't forget the floor. Adjusting the blinds so they angle the sound a bit can help.

You don't want a shotgun, you want a hypercardioid in a tighter pattern, NOT a looser pattern.

In some cases, lavs will work better if you can't get a hyper close enough. I go over a lot of this and more in my little book. http://home.comcast.net/~tyreeford/AudioBootcamp.html

Regards,

Ty Ford
Click to expand...
 
Rippie said:
ty,
i pretty much said all that.

Personally (read:my opinion) I wouldnt waste my time with sheets. way too thin to get any mid range or lower register knocked down.
Now of course if you fold them over 4-5 times..then you might be in business.
Click to expand...

>Great, then don't. My experience is that they do have an effect in my recording studio. Arguing with me isn't going to change that. I've also used a table cloth and other fabric suspended from ceiling lights to reduce table top to ceiling bounce. In general, sound blankets will do a better job over a wider area of frequencies, but anything you can do to take the sting off a wall, ceiling or floor, counter top window or ANY large, hard, flat surface bounce will help.

As for ADR, we live in a world where lip sync seems of decreasing importance. Apallingly so in some cases. I regularly see bad sync on broadcast tv here in the US. Not too many years ago, that content would have been rejected. DTV causes some of this because it takes more time to compress video than audio. As a result, the audio lags the video.

ADR is used a lot more in Bollywood, according to friends I am in contact with. Someone posted a link recently in which they had used ADR. The lines were mostly short and there were no ECUs. With the sync slippage one normally sees in web video, it was difficult to determine how bad the sync might have been.

ADR is also used by indie film makers who get themselves in a jam with inadequate or botched production sound. I get a few calls a MONTH from newbie "film makers" looking for salvation for bad production sound.

For the record: One lav on one actor in a two actor scene won't work unless they are exactly the same distance apart and speak at the same volume and are REALLY, REALLY close to each other. A boom mic pointed who knows where, but not at the actor or at a distance way too far to get good sound can not be corrected in post. There is no plugin to remove echo. Yes, you can knock some frequencies off. Sometimes you get lucky, but most of the time the results still sound like crap. If you over or under record, you will have problems.

Why does this stuff keep coming up? Because really good audio is not as easy as people think. Because inexperienced operators are learning by their own mistakes. That's great, really, and sort of why forums like this exist...so we can sort these things out. But don't kid yourself, there's a lot of craft in getting good production sound. Handing a boom with a shotgun mic plugged into your camera to your roommate, girl friend or boy friend frequently results in a post with the subject line, "How come my sound doesn't sound like the sound I hear in movies?" The answer is Tools and Experience.

About six years ago, I saw the growth in low, low, low, budget indie video production here in the Baltimore and DC area. Some call them "films" but, for the most part, they're shot on tape. I got calls about doing location sound at $100 a day for a 12 hour day for 20 days. Sorry, I can't afford to work for that rate. Then I'd get calls from the same folks after they wrapped to help salvage the production audio. Again, with no budget.

So I decided to help by putting as much of the basic info in a small, easily absorbable book. I'm a federally licensed electronics engineer. I had to do that for my first career, radio broadcasting. In addition to radio production, I've also been producing audio for video and producing music for a long time now. It's great cross-training. Talking theory and formulas was not the way to convey the message. I had to make it easy to get a handle on. I began by doing a few seminars. Asking people to bring their gear and their problems and questions. The idea was to do real problem solving so they could take away tips that pertained to their specific situation.

After one seminar, one of the participants said that although she'd taken notes, did I have any of the material written down. I told her it was mostly sloshing between my ears. She suggested that I write it down...like in a book. Ten months later I was finished. I thought it would help me locally. Selling it to the new wave of "film makers" who couldn't afford me now would hopefully turn into location audio jobs when they grew their business and could afford me.

I put up a PayPal page and, to my surprise, the book started selling in other states and around the world. This Summer, B&H picked it up and you can imagine what happened after that. I am incredibly grateful that people have found it an effective tool to help them in the pursuit of their own dreams.

I probably won't be doing location audio for a shoot in Fiji, Denmark, Alaska or Latvia any time soon, but people in those places will be using the info I wrote down to make their audio better.

Ooops! Coffee's gone. Have a great day.

Regards,

Ty Ford
 
I don't think anybody here has any doubt about your immense knowledge and experience on the sound field and it's an obvious fact that a thin bed sheet is better than a any hard surface to prevent reflection of sound waves. On the other hand, is very obvious than a thick sound blanket will be a less reflective option than a sheet. It's just physics, not an specific sound issue, so we don't need 10 features under our belt to understand that.
You are right , arguing about it is not going to change this fact.
 
tyreeford said:
Why does this stuff keep coming up?
Click to expand...

I think the reason it keeps coming up is because there are always new people looking to learn how to improve their sound. That's a good thing. Could people do more effective searches to find answers to questions many of us have heard over and over? Yes. But at least they are asking the questions and not settling for crappy sound.
 
My (or anyone else) asking such questions implies how serious we are about the audio. The problem people like me face is the lack of resources. "Get a real boom operator", "get a mic set", "change the locations" - these are very good suggestions, and there is no alternative to any of these, but the fact remains that we can't afford most of this, and still want to make quality movies.

So, it is a give and take situation. How to accomplish the most by using half of the resources? Well, I can't get a boom operator, and can't buy another mic. So, based on the suggestions on this board, picked up some PVC pipes and went to Wal-mart and bought 3 more blankets at $4.97 each.

The point is, I wouldn't be doing all this if i wasn't serious about my audio. I am so thankful to some senior members here who, instead of being rude or insulting, appreciate this fact and try to help out.

Like always, I googled to see if I could get any material on the topic; got nothing. This is a topic where experience counts more than anything else. This is why I put up the question hoping someone will guide me, and I am so glad I did as now I know, given my limitations, the best path for me.
 
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