Some basic booming stuff - distance, angle

J

Josh Bass

Veteran
Hey guys. I am not new to production, but I am also not an audio guy, and every once in a while I feel the need to question what I think I know and evaluate it.

I DID search the site for answers, but have not found them.

So:

When using a hypercardioid mic as a boom, I'm curious about a few things.

I've read on here, more than once that 18-22" is a good distance. That's tip of mic to subject mouth, yes? Now, is 18" the min distance and 22" the max distance you'd ever want to be with a hyper? I used a measuring tape to set a mic 18" away from my mouth, and was surprised at how far it is in the real world. In many cases (talking head interview, etc.), you can actually get the mic much closer. SHOULD you? I know about proximity effect with condensers, but, other than that, is there a reason to keep the hyper that far from the subject if you can go closer? Can you ever get TOO close (let's say you were doing quickie on-location VO with that same mic--and I've seen them do this when shooting a series of commercial :30 spots and also doing stuff that's radio only using the same mic, so it IS a real life scenario-- how close would you get?)

That's my curiosity about distance. Also curious about angle. Is it generally recommended to have the mic very close to the head of the subject, and nearly vertical, and only have to angle it a little to get it pointed at the mouth/throat, or better to be further out from the head, and have the mic angled more at 45 degrees or so from vertical to point back toward the mouth/throat? Does it matter? Is it all about where you want to aim the rejection nodes of the hyper pattern?

Thanks.
 
18-22" is a good distance
Click to expand...
That's an estimate of the minimum for decent result. 3-4" is better if you can get it. And yes, that's from the tip. Proximity can be diminished in post, so don't worry too much about it, and the closer you get then the less the surrounding (disturbing) sounds get. As a general rule, get as close as you can without being in shot.

Can you get too close? Yes. At a certain distance of 1-2" you can get pops and wind noise from breathing that doesn't sound too good. The angle can help to reduce this (by not having them speak straight into the mic), but you might have to get a little further away sometimes. You can usually tell right away.

Is it generally recommended to have the mic very close to the head of the subject, and nearly vertical, and only have to angle it a little to get it pointed at the mouth/throat, or better to be further out from the head, and have the mic angled more at 45 degrees or so from vertical to point back toward the mouth/throat? Does it matter? Is it all about where you want to aim the rejection nodes of the hyper pattern?
Click to expand...
'
Good question. I actually did a test of this a few weeks ago, since I was with a mixer that recommended a nearly vertical position, and it felt a bit wrong to me. The more vertical and closer to the head you get, the closer you get, which is good. The problem is that it requires very careful positioning and agile booming as slight movements of the head instantly decreases the higher frequencies (for more directional mics at least). The more you angle it, the further the distance from the mouth becomes, but it also gives you more room for movement and forgiving booming. 45 degrees is in my opinion too much though, and vertical is as said hard to do. I preferred somewhere around 20 degrees as a good compromise. I think it sounds best aiming at the mouth or chest (which from above becomes a very small difference in angle and/or distance). I prefer the chest, as that too gives a bit more leeway for better consistent booming if the subject moves around.

About rejection, it all depends on the surrounding noise. If you have a strong direction from where the noise is, then getting that in the rejection area of the mic can give better result even if the position to the subject is slightly compromised, but it really depends on the situation.
 
Thanks. Regarding distance, I've noticed that at a certain point, seems like things can start to sound TOO "intimate", at least for audio being used with video (I guess unless you're super tight on a face, so the intimacy of the shot matches that of the sound). Get too close, and you get all the "gross mouth noises" (I was surprised when you said 3-4" as that seems to be where this gets really noticeable). I realize some of that is a function of the talent and how they speak, but it seems like some of it can be attenuated with distance. Thoughts?
 
Last edited:
Yeah, that's called "proximity effect". I try to be at max 12-16" above and at a 45 degree pointed directly at talent's pie hole.......I mean, mouth. Obviously, the closer you are, the less the BG noise plays in comparison to the intended signal.

This is where monitoring the signal is crucial, and having a good set of cans. You need to listen for that sweet spot, where BG is there, but gives the editor great dialogue signal.
 
Last edited:
Proximity effect would account for an emphasized "bass-y" tone to the recording, but with condensers, you also generally get "higer definition" if you will, on certain sources such as vocals, which sometimes leads to the clicky/licky/"lip-smacking-good" effects that are a bit over-the-top. I do a fair amount of vocals and voice-over work, and it might help, if possible, to have your talent drink a little water before a take. I've also heard (but keep forgetting to try) that eating an apple will actually help (?). Worth a shot, I suppose. A problem you will most likely not have with booming (because you can't really get too close without getting the mike in the shot; maybe when scooping though?) is a distorted, nasty, bass-y "wind" effect that condensers are susceptible to from both air-pressure and moisture (from talent's mouth), which the microphone element doesn't like much. If you are using a windscreen, and keep your distance (as in booming), it shouldn't be a problem, but if you are ever doing ADR in the studio, make sure to keep at least a 3-4 finger distance between mouth and microphone, and use at least a foam windscreen, or better yet a pop filter (the round "screens" you see in front of studio condensers).

GJ
 
I love the contradictory answers ("45 degrees is way too severe an angle!" "I use 45 degree angle pointed at the mouth"). I kid because I love. So, to be clear, you're blaming gross mouth noises on mic closeness, and talent, or just talent? I wasn't quite able to tell from the post.

Yes, I had always read/heard "proximity effect" specifically referred to the increased bass response (out of proportion to the other frequencies) as a condenser gets closer, beyond a certain point.
 
The really critical thing is simply "what does it sound like?" Getting good sound is not about measurement in inches, or setting angles by degree, it having the experience to listen to the headphones and react in a way that improves or maintains it. Actors move - so does the person with the boom. So any attempt to maintain 45 degrees or X inches just doesn't work. The mic you select will have characteristics that set the best angles and distances, and they will be different to another. That's why sound recordists hate changing their equipment - because they know how it sounds in every circumstance. Some mics, and I really like the Beyer 201 for a hypercardioid use - remain fairly consistent in sound quality as they go off axis, while other hypercardioids I own start to go 'thin' sounding as soon as they move away from the mouth. These would be a nightmare to use on a boom, because it's virtually impossible to maintain target on the mouth that accurately with a boom, that does not have easy change of direction in some directions. The longer the mic, the more difficult aiming becomes if you are close in - so a longer mic further away tends to be just as good in many cases. The closer perspective of a mic closer in soon vanishes if you don't closely track the mouth. A shotgun further away is easier to track - but the key issue is the boom op needs to hear their mic - and you can then react quickly as the sound changes. I often see boom ops with no headphones. They have no idea at all what their sound is like, and these are often the ones who are trying to mentally gauge 18" or 45 degrees or whatever, in the belief that getting these figures spot on guarantees good audio. It doesn't!

If you give an experienced boom op a new mic, unfamiliar to them, you will see them sweeping it about, in front of a speaking subject, establishing that microphones characteristics - how far off axis before it goes thin, how much the sound changes as distance changes. These are critical things to master. As for proximity effect. For this to be noticeable, the boom would be far too close in. Josh's comment about the bass increasing out of proportion is the key. The ratio of wanted to unwanted sound sets the 'timbre' - voice vs room - so as you get closer, the voice becomes more precise and detailed as the room sound component drops off. As you go in, the inverse square law works for you, level wise - proximity effect, where the bass end increases out of proportion isn't usually a problem. If it is, then the cameraman would have already kicked you for being in shot!
 
I love the contradictory answers ("45 degrees is way too severe an angle!" "I use 45 degree angle pointed at the mouth").
Click to expand...
As you can see, it depends on practicality and user preference. My advice of around 20 degree angle is a result of my own experimenting (with a shotgun mic I might add, as less directional mics might have other conditions). I suggest to test it yourself to see what you like (I just recorded myself with the mic on a stand, with several different hights, angles, and distances in front of the head, and also turned my head to see how much off-axis it got - listened to it on proper studio monitors).

Regarding mouth-noise, this can indeed be a serious disturbance, but not something I have thought to be connected to distance, so I would like to hear more about it. I would try to record someone "clickity" both close and further away, then make shure the clips have close to the same levels and compare.

About the "too intimate" sound, I would say it depends on the kind of work you do and if you have someone taking care of the sound in post. If you don't, then you might want to back away if you find it too intimate, but if you work on it afterwards you can remove some of the intimacy by making it thinner with an eq, and maybe add a little reverb and room tone. Others might have more to say on this.

A problem you will most likely not have with booming (because you can't really get too close without getting the mike in the shot; maybe when scooping though?) is a distorted, nasty, bass-y "wind" effect that condensers are susceptible to from both air-pressure and moisture (from talent's mouth), which the microphone element doesn't like much
Click to expand...
I hadn't really thought about moisture from the breath. Is this a clearly audible problem, or should you maybe be wary of placng it to close not to damage the mics?
 
The really critical thing is simply "what does it sound like?" Getting good sound is not about measurement in inches, or setting angles by degree, it having the experience to listen to the headphones and react in a way that improves or maintains it. Actors move - so does the person with the boom. So any attempt to maintain 45 degrees or X inches just doesn't work. The mic you select will have characteristics that set the best angles and distances, and they will be different to another. That's why sound recordists hate changing their equipment - because they know how it sounds in every circumstance. Some mics, and I really like the Beyer 201 for a hypercardioid use - remain fairly consistent in sound quality as they go off axis, while other hypercardioids I own start to go 'thin' sounding as soon as they move away from the mouth. These would be a nightmare to use on a boom, because it's virtually impossible to maintain target on the mouth that accurately with a boom, that does not have easy change of direction in some directions. The longer the mic, the more difficult aiming becomes if you are close in - so a longer mic further away tends to be just as good in many cases. The closer perspective of a mic closer in soon vanishes if you don't closely track the mouth. A shotgun further away is easier to track - but the key issue is the boom op needs to hear their mic - and you can then react quickly as the sound changes. I often see boom ops with no headphones. They have no idea at all what their sound is like, and these are often the ones who are trying to mentally gauge 18" or 45 degrees or whatever, in the belief that getting these figures spot on guarantees good audio. It doesn't!

If you give an experienced boom op a new mic, unfamiliar to them, you will see them sweeping it about, in front of a speaking subject, establishing that microphones characteristics - how far off axis before it goes thin, how much the sound changes as distance changes. These are critical things to master. As for proximity effect. For this to be noticeable, the boom would be far too close in. Josh's comment about the bass increasing out of proportion is the key. The ratio of wanted to unwanted sound sets the 'timbre' - voice vs room - so as you get closer, the voice becomes more precise and detailed as the room sound component drops off. As you go in, the inverse square law works for you, level wise - proximity effect, where the bass end increases out of proportion isn't usually a problem. If it is, then the cameraman would have already kicked you for being in shot!
Click to expand...

All very good advice. Angle and distance is a guidemark, but the situation, mic, and experience of the boom op will decide what sounds good and works for the scene.
 
Dynamic mics tend to be used close in - often with people yelling into them from zero distance - so they frequently have a piece of foam inside to act as a windshield and spit guard. Condensers frequently have far smaller openings, sometimes just one tiny one, so spit is a potential problem, because it can block the opening - this happens frequently on stage with some designs of head worn microphone. However, moisture is usually a problem from a different perspective. Humidity and vapour that condenses on the front diaphragm can short out or severely change the capacitance. Some older condensers get noisier in the damp. With the mic at room temperature, moisture is unlikely to be a problem unless there's an awful lot of it - and at boom distances it's very unlikely. This distance is usually enough to stop blasting too - and in many designs, especially shotgun types, the element is a long way from the opening at the front. Outside of course, moisture can be considerably higher - but again, distance works quite well.
 
>>>>I hadn't really thought about moisture from the breath. Is this a clearly audible problem, or should you maybe be wary of placng it to close not to damage the mics?<<<<

Good advice from several here; experiment and listen... But yes, this issue will be obvious, whether it is moisture/pressure "blasting" from talent's mouth, or from environmental issues... It's hard to describe until you hear it, but you can definitely hear it, and when you do, you'll know what it is. You either move the mike, use a windscreen, or both.

GJ
 
You must log in or register to reply here.
Back
Top