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Old September 18th, 2011, 11:18 AM   #1
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possible for boom mic to be too close?

My general understanding is that the mail goal of booming a mic is to get it as physically close to the talent as possible, within the bounds of the need to keep it out of the shot.

But I've recently run into some sound recordists with more experience than myself, who have a different idea. They think that when recording indoors (a small living room for instance), it's better to keep the microphone a bit further away from the talent, because otherwise the sound gets all congested with the interior sounds laying on top of each other. I'm curious if there's something to this or whether, more likely it's just a miscommunication or misunderstanding. I always thought it is always best to get the mic as close as possible, and if there's a reason to hold it say 5-6 feet away indoors when 2-3 feet is feasible, then please enlighten me.
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Old September 18th, 2011, 04:20 PM   #2
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Re: possible for boom mic to be too close?

I suspect it may be a misunderstanding.

A given talent, speaking at a given level, in a given location within a given room, will produce a given amount of reverberation.

The level of that reverberant sound, within a reasonably sized area, will be fairly constant.

As you move the mic farther and farther from the talent's mouth, you will need to continue raising the mic input gain on the recorder, in order to capture the voice at the correct recording level.

And, as you increase the input gain on the recorder, the level of the reverberant sound will get louder and louder on the track.

The results will be pretty much what you'd expect. As the mic gets farther from the talent (and you increase the gain to compensate), the voice sounds more distant, with less clarity and less presence, and more reverberant sound (as well as more of any ambient background noise in the room).

Note that if the room is fairly small and fairly live, there may be a lot of standing waves at lower frequencies, so that there may be better and worse places to position the talent and the mic. Different locations may yield results that are more or less "boomy." But this does not negate everything stated in the preceding paragraphs.

Of course you want to keep the mic a reasonable distance from the talent's body, and from hard surfaces like desktops, to avoid distorting the directional pattern of the mic, and to avoid comb effect and "phasing" phenomena from near-surface reflections.
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Old September 18th, 2011, 07:26 PM   #3
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Re: possible for boom mic to be too close?

Additionally, the further away from the talent, the more wiggle room the talent has as the pattern gets wider further away from the mic.
If the action is moving too fast to keep the boom 2-3 ft away, further distance can help.
Also, rather than go through the extra steps in post of adding appropriate room ambience, why not mic for a natural sound? If the actors are being shot wide, I'd go for a more roomy sound...if they're close together and being shot tight, keep the mic as close as possible. Essentially miking as if you're in the scene listening.
There is a bit more art to good boom miking than most realize.
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Old September 18th, 2011, 07:54 PM   #4
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Re: possible for boom mic to be too close?

One other consideration is a phenomenon known as the 'proximity effect' where bass begins to get emphasized as the mic get's closer to the speaker. Radio and VO artists are particularly aware of this and go to great pains to discover the optimum working distance for their voices with a particular microphone and maintain it during a gig. Skilled vocal musicians also use mouth to mic distance creatively in their performances. All directional mics exhibit it, the more directional the further away it begins to be a factor. Since shotguns are the most directional, the bass emphasis starts to get noticable when they're further away than would be observed with, say, a cardioid mic. 'Guns will start to build up the bass when they get much closer than about 20 inches, sometimes further, a hyper can work somewhat closer, 15 inches or so, and cardioids will start to exhibit it at around 8 to 10 inches. So the strategy is to find the Goldilocks distance for each voice - as close as possible in order to keep the level of the desired sound striking the mic as high as it can be and yet not so close that the timbre of the voice begins to sound unnatural.
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Old September 18th, 2011, 08:53 PM   #5
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Re: possible for boom mic to be too close?

Robert and Steve both have good points. Perhaps those are things that people were trying to convey to Tom.

I note that Tom's original question concerned recording indoors, supposedly as opposed to recording outdoors. Thus, I was trying to focus my answer on things that would apply indoors, but not outdoors. Mostly, IMHO, that would be issues with reverberation and near-object reflections. Wiggle room, though, would apply outdoors as well as indoors, so that seems like a long shot for the indoor/outdoor question (although it is a valid point to keep in mind anywhere).

Proximity effect certainly exists everywhere and anywhere, the variables being the mic pattern and mic distance, and should not be overlooked. Tom is asking about the pros and cons of 2-3' vs. 5-6', and proximity effect might just start to come into play at a distance of two feet.

It would be interesting to hear exactly what these other recordists said to Tom, prompting this thread. Tom, you weren't rolling tape during that conversation were you? ;-)
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Old September 20th, 2011, 01:28 AM   #6
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Re: possible for boom mic to be too close?

After working with this husband/wife sound recordist duo another day, I've come to a guess... I think it's just their way of working. They like to hold the boom in one position and not move it ever. In my humble opinion this is because they don't use an isolation mount between boom pole and microphone, but the point is that is what works for them and it's their reality even if others who work differently move the boom with action.

Also they strongly favor consistency, making what I found a very good point: that the distance between subject and mic controls how much room tone leaks into the mix, and if you vary this from shot to shot your room tone might pump in and out.

I also appreciated Steve's point about proximity effect; I had always thought of it as applying at distances of a few inches to a foot maximum, so assumed it wouldn't ever apply with an off-camera mic. But to some extent I suppose proximity effect has a long tail where it must have some effect however small at several feetl

The replies on this board always impress me with new things to consider.
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Old September 20th, 2011, 01:37 AM   #7
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Re: possible for boom mic to be too close?

Quote:
Originally Posted by Greg Miller View Post
Tom is asking about the pros and cons of 2-3' vs. 5-6', and proximity effect might just start to come into play at a distance of two feet.

It would be interesting to hear exactly what these other recordists said to Tom, prompting this thread. Tom, you weren't rolling tape during that conversation were you? ;-)
What inspired this was them boom micing a person seated on a couch, with just inches of frame above their head. The cardioid mic could have been placed 1.5-2 feet away and I would have thought that best, but this recordist said no that would sound worse, and kept it 5 or so feet away, closer to the ceiling than subject.

She insisted that was the best position for the microphone, and essentially talked about the tone not being right if it was closer... in retrospect probably referring to proximity effect and similar.

I would think that especially indoors (small living room) the undesirable room reverberations would overwhelm any tonal improvements by a huge margin, but again in retrospect even though she explained it in terms of tone, I suspect there were other factors at play like going for consistency with other wider shots.
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Old September 20th, 2011, 06:44 AM   #8
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Re: possible for boom mic to be too close?

Did these recordists also record room tone in addition to the dialog? It appears they wanted to capture 'the room' during the dialog, effectively doing the post-production sound mix on the fly. Getting the mic as close as possible is based on the idea of recording the speech as clean and free of ambience as you can possibly get it; recording the room ambience separately on a completely separate track from of speech; and mixing them in post where you can control to proportions at your leisure.

You said they used a cardioid mic fixed 5 feet from the subjects? I would be very surprised if it didn't sound remote and a bit hollow. But the proof is in the pudding - if it sounds good it is good.
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Old September 20th, 2011, 09:20 AM   #9
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Re: possible for boom mic to be too close?

Quote:
Originally Posted by Steve House View Post
Did these recordists also record room tone in addition to the dialog? It appears they wanted to capture 'the room' during the dialog, effectively doing the post-production sound mix on the fly. Getting the mic as close as possible is based on the idea of recording the speech as clean and free of ambience as you can possibly get it; recording the room ambience separately on a completely separate track from of speech; and mixing them in post where you can control to proportions at your leisure.

You said they used a cardioid mic fixed 5 feet from the subjects? I would be very surprised if it didn't sound remote and a bit hollow. But the proof is in the pudding - if it sounds good it is good.
Yes I think you are right about the trying-to-avoid-post-work motivation for intentionally capturing room tone on top of the dialog. They did capture room tone seperately too, but expressed a strong preference for doing it right "at the time of recording" rather than in post.

But this is the first time I've thought about the need to add room tone back into overly-close-miked shots... this recordist actually does more post than production work so optimizing that workflow makes sense, and this particular indie no-pay shoot is probably going to be edited by someone else who might or might not understand or be motivated to use room tone well. Politics.
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Old September 20th, 2011, 10:39 AM   #10
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Re: possible for boom mic to be too close?

IMO, five feet away for an interior interview is bizarre.. unless there's a framing issue, then a lav would be in order. My recording of 'room tone' is for post, filling sound in edits and such.. not to add extraneous noise and room reflections, which I attempt to minimize.
I normally move the mic around some to a find a 'sweet spot', but this usually only changes placement by a few inches or degrees on/off axis.
Unless Tom's "sound recordist" associates were looking for a 'special effect', their lack of a shock-mount and mic placement, suggests they really don't know what they're doing. .
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Old September 20th, 2011, 11:17 AM   #11
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Re: possible for boom mic to be too close?

Hi Tom,

I have a very good idea about whom you are speaking and to be honest I do not agree with this method of capturing location sound. No matter what, for films, good sound is designed and not just captured in one take IMHO. Again this is my opinion but wanting to "minimize" work in post is no excuse for picking up mediocre sound and unfortunately that is what happens on many small productions. There are situations when time is a constraint and you don't have time for good post sound design but those times are rare (like doing a 48 hour film, even then you build it into your schedule).

The problem with trying to capture room tone along with dialogue is that then you are stuck with it. In a lot of situations we'll have the talent do walking scenes without shoes if they are making too much noise. We add the footsteps back in in post. Of course if you have full body shots of walking characters then you have to pick up good dialogue in another way, sometimes that means the dreaded ADR.

There is a balance that has to be achieved between getting dialogue that is clean and capturing it with enough of what I refer to as air, or capturing a good spacial feel tot he sound (this is going back to my stereophile days in describing sound). For most mics I've used on sets that's between 1.5 to 2.5 feet from the speaker. The problem with trying to capture location dialogue without having to aim the mic, even with a cardioid, will require you to be too far away to avoid tonal shifts and differences in volume as the talent moves through the scene. You will also have to crank up the gain on the mic to a point where you will be introducing additional and needless noise in your recording chain.

It depends on the mic and this is where the sound person needs to know their equipment. Also, as Steve noted, a good boom op will be able to position the mic so that they get the right tonal balance so that the talent sound natural and full. Another issue with most small productions is not just that the sound has echoes, and obtrusive background noise, but the dialogue is often thin sounding. I would rather capture the cleanest dialogue I could, and have a slight bit more bass as long as it isn't becoming muddy or starting to mask over the mid and higher range. I can always EQ out the lower frequencies in post and still have it sound natural. Bumping the lower registers in post usually yields much less natural sound.

One of the things to remember for narrative projects, is that we are not going to present sound in a way that is exacting how it sounds on set. The goal is to use sound so that it enhances the storytelling and allows the director to emphasize his points. In many cases we'll present the sound in a very unnatural way. Imagine a scene in a dinner where there is a lot of background chatter and two characters are having a conversation. In real life the background noise is very loud compared to the dialogue. In real time, we have the incredible ability to filter out the background and concentrate on what is being said. When watching a movie we don't have that ability. So we drop the levels of the background chatter and the clinking dishes are still there but are a lot softer. The only way to do this is to capture each sound separately and layer them so that we achieve the experience desired.

Sound design and location sound is one of the areas that gets overlook in many small productions and IMO there is no excuse for it. Every good person doing post production sound that I've worked with expects to be building the soundtrack from a number of sources, heck that's what they love to do. The biggest problem is when they get crap they can't work with from the production and are having to bandage the sound together.

Sorry for the long post but bad sound is a pet peeve of mine. And, as always, these are just my views and don't necessary reflect the views of others.

-Garrett
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Old September 20th, 2011, 11:19 AM   #12
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Re: possible for boom mic to be too close?

Tom

You're a SC member correct? If so, I'm working on a project that could use some more people in various departments. We've got a shoot coming up on October 2 that at last check with the producer, we needed another boom op on. Let me now if your interested and available. We also have a number of other shoot days going through November.

-Garrett
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