Questions on Sound in Filming Videos

[leroyjenkens]

I have a few questions about filming videos because I want to make a film. I noticed that when I make videos with my kinda crappy camera, even filming in an ostensibly quiet room, the video has some sound in it. Like a humming sound. Where could that be coming from? Electrical equipment? Or maybe the microphone in the camera is bad? I looked up a couple of example videos of cameras I want to buy, and I hear the same thing in their videos. But I don't know how their room sounds in person. If I have no electrical equipment on, the microphone is good, and the room is silent to my ears, should the sound on the video also be silent? I'd like to have a perfectly silent video except for the sounds I want, so I don't have to edit out anything, which would probably make things a lot harder.
Thanks.

 

[collinsmark]

Shooting good videos can get really expensive really quick*.

But if you want good sound quality, one of the things you'll want to invest in is an off-camera microphone and boom.

The camera's microphone shouldn't be used for good sound quality, or if it is used, should only be used as a last resort. The on-camera microphone's main source of sound might be coming from the camera itself. But by plugging in an off-camera microphone into the camera's microphone input jack, you can move the microphone closer to the subject, where it should be.

It doesn't have to be as fancy as the one pictured above. You might want to google "microphone boom" to build your own. Microphones themselves vary in price quite a lot. But even a cheapy one, off-camera, should still be an improvement to the on-camera mic.

*(The grammar police in me knows this should be "quickly," but I'm feeling on the edge today).

 

[collinsmark]

Also, you camera might have automatic gain control (AGC) regarding the sound volume recording.

If at all possible, turn this feature off! (when shooting scripted scenes)

AGC tries to be helpful by adjusting the recording volume depending on the ambient volume. The idea is that most users are too lazy or too ignorant to adjust the sound recording volume manually. If you are in a loud environment, the recording volume is automatically decreased. In a quiet environment it is increased. That's probably fine for something like home-movies of the kids and family.

But AGC is god-awful of you're tying to make a decent film. It means if you are recording in a silent room, the AGC cranks up the recording volume to maximum, amplifying every silly noise and vibration there is whether you want it to or not.

If your camera allows you to turn AGC off, do so, particularly when you are making scripted movies. Do however, pay attention to the ambient sound and adjust the sound recording volume manually, if your camera allows you to do so. The recording volume needs to be low enough such that no sound that you are recording/filming causes "clipping" or distortion. And it should be high enough to get all sound minutia that you want to capture. (At the very least it should be high enough such that the subject's sound is clean and clear, above the noise floor. But not so high to cause clipping. If you desire any background noise, you can always record it independently [via foley or the real thing] and mix it in later, in post.)

 

[leroyjenkens]

That's a good idea about the boom, that is a way to make it sound more professional, instead of the voice of someone across the room sounding like they're far away. I wanted to try my first film by myself. Is it possible to do the boom thing without someone holding it?

Thanks for the tip about the AGC. It does sound like my camera is doing that. I need to look online for a manual on how to turn it off if it's on, since I bought this used.

I also had another idea about constructing something that could hold my camera and I could adjust the height and be able to tilt it. Any ideas on how I could do this for cheap? I was thinking about something that could hold the camera and have it slide up and down a pole, and have a screw or something to lock it in place. I'll have to visit Home Depot or something and see what they have.

 

[zoobyshoe]

I also had another idea about constructing something that could hold my camera and I could adjust the height and be able to tilt it. Any ideas on how I could do this for cheap? I was thinking about something that could hold the camera and have it slide up and down a pole, and have a screw or something to lock it in place. I'll have to visit Home Depot or something and see what they have.

Just get a tripod.

Look on the bottom of the camera and there is almost certainly a screw hole into which a tripod screw will go. They're standardized. Also, all tripod heads tilt and pan.

Look on craigslist or at flea markets or yard sales (or, just borrow one.) Bring your camera with to make sure there are no problems before you buy. (A lot of tripods have a removable screw mount that is lost or missing, and the leg mechanisms are damaged on some used tripods. Make sure you can mount your camera, tilt and pan it, and adjust the tripod up and down.)

There are different sizes. Some are taller than others. Short ones can be made taller by setting them on a table if you need a high angle. Tall ones can be made shorter by shortening the telescopic legs and/or adjusting the top section, which cranks up and down. Tripods are invaluable for any kind of still or motion picture photography.

 

[leroyjenkens]

Oh yeah, can't believe I forgot tripods existed. I thought I was inventing something. Thanks.

 

[zoobyshoe]

Oh yeah, can't believe I forgot tripods existed. I thought I was inventing something. Thanks.

You can buy self-standing mike booms, too, such as what musicians use (guitar/singers). I have no idea what they cost, though.

 

[leroyjenkens]

You can buy self-standing mike booms, too, such as what musicians use (guitar/singers). I have no idea what they cost, though.

And the purpose of those is to basically get the sound closer to the person talking, correct? Like if the camera is on one side of the room near one person, then that person sounds fine, but a person on the other side of the room won't sound as good and will sound far away and maybe echoey, which makes it sound amateur.

 

[zoobyshoe]

And the purpose of those is to basically get the sound closer to the person talking, correct? Like if the camera is on one side of the room near one person, then that person sounds fine, but a person on the other side of the room won't sound as good and will sound far away and maybe echoey, which makes it sound amateur.

I mentioned them in answer to your question:

Is it possible to do the boom thing without someone holding it?

In the meantime, I also remembered the clip mike. That's an alternative you could explore.

In both cases the point is to get the mike nearer the person actually speaking and away from the mechanical noises produced by the camera.

 

[collinsmark]

And the purpose of those is to basically get the sound closer to the person talking, correct?

Yes, that is correct. It is also true that you want to get the microphone closer to anything that you attempting to record, so long as its not so close that it causes distortion/clipping in the microphone itself (e.g., if you are recording an explosion, it's not necessary to put the microphone right next to the TNT. But for most other things, the closer the better).

When using an omnidirectional microphone, the recording sound intensity falls off at at $\frac{1}{r^2}$, where $r$ is the distance between the camera and the whatever it is producing the sound.

For example, suppose the camera's internals make some sort of tiny hum, with 1 unit of power. Let's assume that the camera's microphone is 5 cm away from the source of the hum. Also suppose that there is a person 5 meters away that is the subject, and that person is talking with a sound power that is 10,000 units of power (10,000 times as loud as the camera's hum).

The recorded volume of the internal hum, in our arbitrary units, is $\frac{1}{0.05^2} = 400.$

The recorded volume of the person, in our arbitrary, units is $\frac{10,000}{5^2} = 400$

Which means the camera's internal hum sounds as loud as the person. Obviously, getting the microphone off the camera and closer to the person is advantageous.

There are other types of microphones besides omnidirectional, such as cardiod or hypercardiod (your on-camera microphone is probably a cardiod, I'm guessing), that have a little different characteristics in terms of directionality, but even with that, I'm sure you get the idea.

Like if the camera is on one side of the room near one person, then that person sounds fine, but a person on the other side of the room won't sound as good and will sound far away and maybe echoey, which makes it sound amateur.

There's a couple of options here.

Typically in this scenario, the camera will only be focused on one person at a time. The scene is shot multiple times with a given actor (usually the one that is speaking) being the subject of the camera. Not only is the camera repositioned, but the microphone is too. It means that the actors need to repeat the same scene over (and over and over sometimes). Then everything is edited together later in post, so it seems like there is only one conversation with no repeats.

For reasons of continuity, it is also a good idea to record the background noise (if there is any) separately. For example if they are in a restaurant, record ambient restaurant noises (without the microphone being close to anybody) for at least the duration of the scene. Then mix that audio in with the rest as the final step in post. (Also, if you have control, have all the other extras -- the other customer and waitstaff in the restaurant scene -- be dead quiet when you are filming the characters' conversation. Have the extras pretend to talk to each other, but while actually remaining silent. Only have them actually converse when you're filming the background track. Of course you might not be able to have this much control, but I'm just saying this is how it's actually done in the industry.)

On the rare occasion where both characters are to be talking in the same shot, place an omnidirectional microphone somewhere in-between them, or perhaps better, use a voice-over for one of the characters (only record one character at a time, and mix the audio together in post).

 

[jtbell]

Is it just me, or does anyone else think it's odd to talk/write about "filming" in an all-digital age? :uhh:

 

[zoobyshoe]

Is it just me, or does anyone else think it's odd to talk/write about "filming" in an all-digital age? :uhh:

Aren't major motion pictures still recorded on film?

edit: Yeah, here under the heading "technology":

Film stock consists of transparent celluloid, acetate, or polyester base coated with an emulsion containing light-sensitive chemicals. Cellulose nitrate was the first type of film base used to record motion pictures, but due to its flammability was eventually replaced by safer materials. Stock widths and the film format for images on the reel have had a rich history, though most large commercial films are still shot on (and distributed to theaters) as 35 mm prints.

http://en.wikipedia.org/wiki/Film

 

[leroyjenkens]

Lot of good information guys, thanks. I've been looking at cameras, and I think I'm going to get one of those little camcorders that Panasonic or Sony makes. They seem pretty good. I can get a used one for about 150$. I want to get an external microphone for them, but some camcorders don't have the external mic jack, I've heard. I'd have to search to find if the specific camera I'm looking at has it.
And do all camcorders have a hookup for a tripod? And would it have to be a specific tripod, or are tripods one size fits all?

Can anyone here recommend a camcorder for me that's within 150$ used, and fits my specifications? I'm looking on Amazon right now and there's a lot to choose from. I'm completely new at this, so it's taking a while to sort through and find what I'm looking for.

Thanks.

In the meantime, I also remembered the clip mike. That's an alternative you could explore.

In both cases the point is to get the mike nearer the person actually speaking and away from the mechanical noises produced by the camera.

I'm making a student film, so I want the mic hidden. I was looking at cordless mics, and they can be pretty expensive. I'm going to try to get a cheaper one since it doesn't have to be perfect.

For reasons of continuity, it is also a good idea to record the background noise (if there is any) separately. For example if they are in a restaurant, record ambient restaurant noises (without the microphone being close to anybody) for at least the duration of the scene. Then mix that audio in with the rest as the final step in post. (Also, if you have control, have all the other extras -- the other customer and waitstaff in the restaurant scene -- be dead quiet when you are filming the characters' conversation. Have the extras pretend to talk to each other, but while actually remaining silent. Only have them actually converse when you're filming the background track. Of course you might not be able to have this much control, but I'm just saying this is how it's actually done in the industry.)

My first film is going to just be me as the actor, and I'm going to be playing 2, or maybe 3 different characters. I haven't written anything down, but I have the entire idea in my head, including the blocking and part of the script.

 

[Ben Niehoff]

Aren't major motion pictures still recorded on film

No, they moved to digital a few years ago. Some people still do art films in film for the film-y effect. But almost all movies are shot in digital. Usually with very expensive cameras that shoot at 2x or even 4x HD resolution (i.e., 2048 or 4096 lines instead of 1024).

Overall, I think digital is actually cheaper. In the days of film, a typical motion picture consisted of over a mile of film (maybe it was three miles?). And that's just the finished, edited product. Digital movies can be shipped around easily as stacks of hard drives, and digital editing is much easier and faster than film editing. Not to mention CGI, which is used all the time now (sometimes even to create the entire background ANd costumes!).

 

[zoobyshoe]

But almost all movies are shot in digital.

But the wiki says:

though most large commercial films are still shot on (and distributed to theaters) as 35 mm prints.

Notice it says "large commercial films," not indy/art films.

I don't have any personal knowledge of what's being used, and am not claiming the wiki is right, but I'd need some kind of reliable citation to overturn the wiki assertion in my mind.

 

[zoobyshoe]

And do all camcorders have a hookup for a tripod? And would it have to be a specific tripod, or are tripods one size fits all?

I have never encountered a camera that didn't have the threaded hole for mounting on a tripod. Regardless, if you're worried about it, see if you can find the specific camera you're interested in at, say, Target, and physically examine a specimen to see if it has the screw hole.

I have also never encountered a non-standard hole or tripod. Every camera I've ever had fit every tripod I've ever had. The screw size seems to be an industry standard.

You're main problem might be a used tripod with a removable camera mount that is missing. These are quick-release mechanisms, so a photographer can unmount the camera in a second if a hand-held shot is suddenly called for. A lot of photographers leave them screwed to the base of the camera and don't return them to the tripod. That renders the tripod unusable.

 

[edward]

It has been my experience that most of the hand held video cameras I have owned had the microphone on the back. My voice would always be louder than the people I am digitizing. :tongue:

Edit: Some cameras do have an external microphone input.

 

[Ben Niehoff]

But the wiki says:

Notice it says "large commercial films," not indy/art films.

I don't have any personal knowledge of what's being used, and am not claiming the wiki is right, but I'd need some kind of reliable citation to overturn the wiki assertion in my mind.

I live in Hollywood, a block away from EFilm, and I know people who do this. Believe me, practically every major motion picture is a stack of hard drives.

Some of the older directors might use film for nostalgic reasons. But that is not typical. I don't know who wrote the Wiki article, and when.

 

[leroyjenkens]

I bought my camera and it seems pretty good. It's a Canon HF100. Now I need to figure out what I'm going to do about the sound. When I record video, the microphone on the camera is staticky. I want to get an external microphone for this thing, and I was thinking about getting a lapel mic; one that clips onto your shirt. But for making films, I can't have that be visible. I was thinking instead, I could have the mic taped to the ceiling or somewhere near where the actor is standing. Just somewhere out of view. Would that work, or do those mics need to be near the person's mouth for it to sound right?
Thanks.

 

[MarneMath]

I live in Hollywood, a block away from EFilm, and I know people who do this. Believe me, practically every major motion picture is a stack of hard drives.

Some of the older directors might use film for nostalgic reasons. But that is not typical. I don't know who wrote the Wiki article, and when.

It's funny because if you look at the wiki about 35mm film

Until a few years ago the ubiquity of 35 mm movie projectors in commercial movie theaters made it the only motion picture format, film or video, that could be played in almost any cinema in the world. However since 2008, the rapid conversion of the cinema exhibition industry to digital projection has seen 35 mm film projectors removed from many projection rooms as they are replaced by digital projectors. As of the end of 2012 only about 30% of cinemas worldwide were still screening current release movies from 35 mm film

http://en.wikipedia.org/wiki/35_mm_film

The wonderful world of wikipedia.

 

[AlephZero]

Some of the older directors might use film for nostalgic reasons. But that is not typical. I don't know who wrote the Wiki article, and when.

Another issue is that AFAIK no company is still manufacturing film-based cine cameras. That is not a short term problem, because existing professional quality cameras will probably work fine for another 50 years or so, given proper maintenance and no accidental damage, but it's a clear indication where the future is heading.

Also several companies have stopped manufacturing cine film stock.

Actually this isn't just an issue for the movie industry. We use some specialized high speed film cameras (up to 10,000 frames per second) for filming engineering tests which are now "irreplaceable", and there are no commercially available digital cameras with the same specification (i.e. the combination of speed and pixels per frame).

The Wiki article Zooby referenced says it was translated from Wiki France, and the French are rather fiercely independent about their own film industry. I was bemused by the picture of the Bolex H1 camera "used as a basic camera in film schools". I used one of those back in the equivalent of high school in the 1960s - and the camera was about 20 years old even then. Back in the 60s there were regular arguments about the relative superiority of Bolex and Bell & Howell cameras (fondly known as Bollox and Hell & Bowel...)

 

[zoobyshoe]

The Wiki article Zooby referenced says it was translated from Wiki France, and the French are rather fiercely independent about their own film industry.

I didn't notice that. It explains a lot.

Still, I'm surprised someone hasn't rewritten the article.