Question about using blankets to mask out echo.

I

ironpony

Carbonite Member
I am shooting my own indie short film. I tried to do all of the reading on filmmaking as I could to try to satisfy the actors, but am left mostly to do the crew work as well, besides directing. Out of the all articles I read on how to get good sound recorded properly, there is one thing I missed. Blankets on C-stands. I didn't know filmmakers used C-stands to hang them on. Now what I did is I put some blankets on the floor and hung some on a couple of lawn chairs hear and there but I didn't have a lot of control over the sets that were lent to me, and it's mostly guerrilla shooting, in a smaller time frame, than ideal. Now I've already shot half the movie, so does this mean that I recorded the audio improperly to the point where it can't be redeemed in post? I am not at the post phase yet, and have not done much audio editing actually.

Bottom line is did I screw up the audio by not hanging the blankets on something as high as a C-stand? Plus I didn't get as many lawn chairs to hang more on, that would have been ideal either.
 
You'll have to review the footage to see if it's usable.
In future shoots, it would make things easier if you can review the footage and sound on location (A decent monitor and good headphones). That way you can check to see if everything is ok before committing.

Is ADR an option?
 
Sound blankets to reduce "echo" (what you're really doing is trying to cut down reflections) may not help much. It depends on the room as well as how and where they're hung. What are much more important are mic selection and placement.

What kind of mic are you using, and how are you using it?

Also, the only way to ensure that your sound is usable is to monitor it while you record. If you aren't listening as you shoot, then you will have no idea what you have until you hit the edit bay... and that's a pretty lousy time to find out that your sound isn't usable. If you monitor as you record, just as you use the camera's viewfinder as you shoot, you can detect problems as they occur and fix them before it's too late.
 
Never really used blankets. Just correct mic placement, mic selection and the odd hall carpet runner.

I imagine if you used blankets in the room you would have to pay close attention to continuity. Remove one blanket for a shot will make the room sound different and so on..
 
Duvets are much better than blankets - they're a little better at LF - what you stick them on doesn't matter - where you place them does. moving them just a foot can be easily heard on headphones. You simply need to stand in the room and listen - the absorption can be heard and you can hear the success quite easily (or failure).
 
I am using the FR-2LE sound recorder and NTG-3 mic. I try to get the person aiming the boom, to aim the mic towards the blanketed floor as much as I can. It's hard to tell through the headphones, because the volume of the headphones is different from the volume of a TV. What sounds like it's loud enough through the headphones, might have to be turned up louder on a loudspeaker. And in order to reduce echo, I have to reduce volume a little while recording. So I can't tell really so far much, until after the shoot is over, and by then it's too late, and I have to use ADR or/and tweak what I have, if possible.
 
You do know that shotguns are designed for outdoor use dont you? The proper mic for indoor dialog would be a hypercardioid such as the AT4053b (as a budget level hyper mic). Hypers sound more natural in a reflective situation.
 
Aim towards the floor? I expect you mean aim towards the mouth, from above so there is something absorbant behind the person?

The ratio of 'echo' - it's actually reverberation is exactly the same if you turn the level down - direct and indirect are exactly the same in proportion. What you need to do is change the distance - so the direct is louder than the distance reverberation.

If you clap your hands, and hear two distinct claps, this is echo. If you clap your hands and it sort of rings as it decays - this is reverberation.

Your person with the microphone MUST have headphones, then they will hear what the mic captures. Do NOT turn the level down, because bring it back up at the edit stage brings with it extra noise, making it worse. If it sounds like a church, and the wanted sound is masked by the reverb, get the mic in closer. That is the only thing you can do. It's all about distance, and if it's as bad as you say, I'll guess that the mic is a long way away. More than 4 feet, and you start to hear the room loudly if it's live sounding. The sound op needs to work close in, and communicate with the camera op.

Short shotguns are quite OK indoors when they have to select sound. A short shotgun on a Fischer boom is still quite common in TV studios world wide. Outside, reflections are rarely a problem - but personally, I'm more happy with a 416 or a Rode indoors than a hypercardioid - unless the operator is not so good, where the hyper is more forgiving. I don't subscribe to the no shotguns indoors approach myself.
 
paulears said:
I'm more happy with a 416 or a Rode indoors than a hypercardioid - unless the operator is not so good, where the hyper is more forgiving.
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This is the issue for a very large percentage of indie filmmakers. They lack audio knowledge, and they lack the funds to hire someone who does. As a result they tend to have someone with even less audio knowledge than themselves swinging the boom and monitoring the audio - if they monitor the audio at all. And they lack a selection of mics. They will generally have an NTG-2 or AT897 (or something similar) at best - and 1/3 of the time it's probably plugged directly into a DSLR. A cheap cardioid or hyper in these circumstances will be a bit better than a shotgun.

In this situation the copious use of sound blankets (moving pads and comforters are what is usually used) can be a help. IMHO the slight change in sound (remember who's booming) is worth the trade off for capturing more intelligible dialog.
 
ironpony said:
I am using the FR-2LE sound recorder and NTG-3 mic. I try to get the person aiming the boom, to aim the mic towards the blanketed floor as much as I can. It's hard to tell through the headphones, because the volume of the headphones is different from the volume of a TV. What sounds like it's loud enough through the headphones, might have to be turned up louder on a loudspeaker. And in order to reduce echo, I have to reduce volume a little while recording. So I can't tell really so far much, until after the shoot is over, and by then it's too late, and I have to use ADR or/and tweak what I have, if possible.
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This difference in volume you mention, between headphones and a TV or powered monitor/speaker system... this isn't an issue. And if it is, you need to re-examine what you're listening for and how you listen for it.

Your ears are the tools to listen for the quality of sound: presence of noise, distortion, crackles, background sounds like phones and planes and traffic and household appliances, and the ratio of direct sound to reflected sound. Past that, you need to set your recording level properly using the recorder's meters. Eyes and ears work together during production. Dialog should be reading between -20dB and -12dB on the FR2-LE's meters, peaking at -12dB with an occasional hit as high as -6dB (sudden, loud noises like claps and coughs and door slams). Once you've got that set, the headphone level can be adjusted as needed so that you hear what you need to hear.

When it comes to playback in the editing bay, the dialog mix should maintain the same levels in the end. Monitor level is set to an appropriate listening level, but audio meters still matter.

As for the mic, it's already been mentioned that shotgun mics are, generally speaking, a poor choice for indoors. This is especially true if you don't know what you're doing. The aforementioned hypercardioid will give you much more leeway for interior dialog. That said... the key to making any mic work for dialog is proper placement. You have an effective working distance of no more than 20" from the actor's mouth, and the closer the better. If you can get in as close as 8", do it. The further away the mic is, the lower the dialog:reflection ratio that you'll have and the more "roomy" the dialog recording will be. The mic should be overhead, slightly in front of the actor, and aimed at the sternum.
 
Yeah I meant aim towards the mouth, with the carpet beneath them. I know cardioids are better for that now, and should have gotten one in retrospect. I'll ADR what I have to, if it's too quiet. The sound op that was suppose to do it, left just before shooting started so I had to get my friend. I tried to get her to aim as close as she could but I had so much to do as director I couldn't concentrate on how high the mic was the whole time. I don't think it exceeded four feet though.
 
ironpony said:
I am using the FR-2LE sound recorder and NTG-3 mic. I try to get the person aiming the boom, to aim the mic towards the blanketed floor as much as I can. It's hard to tell through the headphones, because the volume of the headphones is different from the volume of a TV. What sounds like it's loud enough through the headphones, might have to be turned up louder on a loudspeaker. And in order to reduce echo, I have to reduce volume a little while recording. So I can't tell really so far much, until after the shoot is over, and by then it's too late, and I have to use ADR or/and tweak what I have, if possible.
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Headphones are a very unreliable guide to setting levels for a take because as you have learned, what you hear is dpendent on both the recording level settings, which does affect the recorded take, and headphone playback level settings, which don't affect the recording. Riding gain if necessary during the take as the source gets louder or softer, yes. But for setting master levels and evaluating if it's the right level for it to sound right in the final editied show, no, tht's impossible. If you're hearing echo or reverb in the phones, you can't fix it by turning down the level - that doesn't change the relative levels of echo versus desired sound anyway, the desired sound and the undesired sounds will be the same as befoire when you turn it back up in post, only with more noise added in due to the low recording level. Instead you adjust the room until the echo is gone and do a retake.
 
paulears said:
...Short shotguns are quite OK indoors when they have to select sound. A short shotgun on a Fischer boom is still quite common in TV studios world wide. Outside, reflections are rarely a problem - but personally, I'm more happy with a 416 or a Rode indoors than a hypercardioid - unless the operator is not so good, where the hyper is more forgiving. I don't subscribe to the no shotguns indoors approach myself.
Click to expand...

Yes, but ... TV studios are designed to minimize reflections. The admonition not to use shotguns indoors is based on the assumption that one is shooting in a typical residential or office location, which are highly reflective spaces. Acoustically conditioned TV studios and sound stages are a whole different sonic critter altogether, much more similar to the great outdoors than they are to more typical interiors, and 'guns will be perfectly fine there. But in a reflective environment the hyper gives you almost the same side rejection and reach that you would get with the shotgun without concern for the 'gun's comb filtering effects caused by the interaction of direct and indirect sound inside the interference tube. Also remember the hyper exhibits a consistent directional pattern over the entire frequency range while a 'gun's directionality is highly frequency dependent, becoming almost omni at low frequencies. That inconsistent pattern means it doesn't do as good a job filtering out those frequency components of sound arriving from off-axis as does the hyper.
 
ironpony said:
Yeah I meant aim towards the mouth, with the carpet beneath them. I know cardioids are better for that now, and should have gotten one in retrospect. I'll ADR what I have to, if it's too quiet. The sound op that was suppose to do it, left just before shooting started so I had to get my friend. I tried to get her to aim as close as she could but I had so much to do as director I couldn't concentrate on how high the mic was the whole time. I don't think it exceeded four feet though.
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Four feet is way too far for dialog recording. The optimal working distance for a short shotgun is usually about 18 to 22 inches from the speaker's mouth, held just out of frame directly above the camera line pointed down at about a 45 degree angle, aimed directly at the speaker's throat (not mouth, in order to get some of the resonance coming from the chest area). Aim is critical in a 'gun, the pickup pattern is only about 15 degrees wide so +/- 7.5 degrees around dead-on centre is about all the leeway you've got - that means your boom operator has to imagine a circle maybe 8 inches in diameter around the character's throat and keep the mic aimed directly into that circle no matter how the character moves.

Cardioids are NOT better, HYPER-cardioids are. They are two entirely different pickup patterns. The cardioid is wide, covering an angle of about 180 degrees with sources starting to sound off-mic around the +/- 60 degrees off-axis. The hyper-cardioid or super-cardioid is quite a bit narrower, picking up well within about a +/- 30 degree off-axis wedge coming out the front and with much better side rejection (but somewhat less rear rejection) than the plain cardioid. Because of the side rejection, narrower pattern mics (hypercardioid) can be used further away from the subject than can wider pattern mics. Adjusting the gain so the levels match with the varying distances (ye olde inverse square law in action), a cardioid needs to be 8 to 12 inches away from the subject to sound the same as would a hyper held at 18 inches and a shotgun at 24 inches.
 
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Okay thanks for the input.

Steve House said:
Headphones are a very unreliable guide to setting levels for a take because as you have learned, what you hear is dpendent on both the recording level settings, which does affect the recorded take, and headphone playback level settings, which don't affect the recording. Riding gain if necessary during the take as the source gets louder or softer, yes. But for setting master levels and evaluating if it's the right level for it to sound right in the final editied show, no, tht's impossible. If you're hearing echo or reverb in the phones, you can't fix it by turning down the level - that doesn't change the relative levels of echo versus desired sound anyway, the desired sound and the undesired sounds will be the same as befoire when you turn it back up in post, only with more noise added in due to the low recording level. Instead you adjust the room until the echo is gone and do a retake.
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So you're saying that the gain (trim) knob is for setting the levels to make it loud enough, but the other bigger level knob, on the recorder, does NOT make a difference in post?
 
He said adjusting your headphone level doesn't affect the recording. The level at which you record at will defiately affect the recorded audio but lowering it to get rid of echo does not work. Fixing your reflections is what you need to do. That and hiring a sound guy if possible.

Steve, I tend to agree with Paul when choosing a mic. Many people here say hyper indoor, gun out. Maybe good advise to someone that doesn't know what they are doing but I will choose what mic sounds best... I usually prefer the sound I get with a gun. That being said I sometimes prefer the pickup from a hyper, or even a cardioid. The only rule or advise I would give when it goes to which mic to use is, your ears.
 
Chadfish said:
You do know that shotguns are designed for outdoor use dont you? The proper mic for indoor dialog would be a hypercardioid such as the AT4053b (as a budget level hyper mic). Hypers sound more natural in a reflective situation.
Click to expand...

Yes, but it could be he spend the last of his money to the NTG-3.... But I don't know if it's better to first by a shotgun and afterwards a hypercardio, or first a hypercardio en then a shotgun....
I think it's less "crimefull" to shoot with a shotgun inside, then with a hypercardio outside.... Even with the reflections.

And it also depends what you're doing: if it's news gathering...always shotgun, don't mind the reflections, just let it go... because there's no time to change it (and no money to putt 2 mics on the invoice)
Even for company movies it doesn't matter.
 
dre83 said:
Yes, but it could be he spend the last of his money to the NTG-3.... But I don't know if it's better to first by a shotgun and afterwards a hypercardio, or first a hypercardio en then a shotgun....
I think it's less "crimefull" to shoot with a shotgun inside, then with a hypercardio outside.... Even with the reflections.

And it also depends what you're doing: if it's news gathering...always shotgun, don't mind the reflections, just let it go... because there's no time to change it (and no money to putt 2 mics on the invoice)
Even for company movies it doesn't matter.
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Agreed - for me, I have both a Schoeps CMC641 and a Rode NTG-3 in my kit so I'm covered where ever I end up. The problem I have with 'guns is not the echo's, it's the ringing hollow sound they can exhibit in the presence of early reflections and that the directionality is lost at the low end
 
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Okay thanks. I wish I had splurged the extra cash on a cardioid, at the time. I did have a sound guy, but he had to leave just before shooting, cause of a personal emergency back home. He told me he prefers the shotgun, since cardioids have had other problems for him indoors. But I called some stores and one said they might have the AT4053b, but they didn't look to confirm. I will have to go down to see if they actually do. If that's a good mic, I'll get it, cause then I can shoot the rest of it with that one. But is it just as good as say... the NTG-3?
 
ironpony said:
Okay thanks. I wish I had splurged the extra cash on a cardioid, at the time. I did have a sound guy, but he had to leave just before shooting, cause of a personal emergency back home. He told me he prefers the shotgun, since cardioids have had other problems for him indoors. But I called some stores and one said they might have the AT4053b, but they didn't look to confirm. I will have to go down to see if they actually do. If that's a good mic, I'll get it, cause then I can shoot the rest of it with that one. But is it just as good as say... the NTG-3?
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HYPERcardioid. Not cardioid. There's a very large difference. If your sound guy said he doesn't like cardioids indoors, that makes sense. Hypercardioids, however, will perform quite differently and should be just what the sound doctor ordered.

The 4053b is a hypercardioid, and it's a good mic. Just as good as the NTG-3? Well, if used properly and in the right setting it will get you very nice results. Beyond that, comparison of the two is really apples to oranges.

Not that shifting gears like this halfway through the shoot will result in a major sound discrepancy. Half the film will sound better than the other half. This doesn't mean you shouldn't try to improve your sound, but it means that you'll have your work cut out for you in post. You may have to ADR, or do some other major doctoring, to the half that's already been recorded.

Back to proper recording levels and the FR2-LE, please read my previous post. And after that, here's a little step-by-step:

Start with the mic trim all the way down. Bring the recording level (larger rotary control) up to 1:00-ish (1 mark past center). Bring the mic trim up slowly until you've reached proper recording level on the meters. Note that you don't really want to drive the pre-amps much past 75%, so if you find yourself having to do that simply drop them back down just a touch and use the record level control to make it up.

Once you have the right recording level set by the meters, adjust the headphone level as needed.

Also, you might want to consider this training resource, which will clear up a lot of the beginner mistakes:

http://dvxuser.com/articles/dvxshop/SoundDVD/
 
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