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Recording Good Sound For Film and Video


By Robert Alstead - Posted on 10 February 2004

Reading about Hollywood editor Walter Murch's experiences of recording and editing sound (see last week's column), really brought home the point that good audio can make a world of difference to any movie project, whatever the scale.

I knew this before, but now I really know it. As a friend of mine, David Hechenberger, who works as a sound recordist at Location Sound in Vancouver, often points out, "Getting good sound is one of the most affordable things that you can do to up your production values and make your movie look better". Meanwhile, a bad soundtrack blares "amateur".

If sound is half the movie, then why is it often ignored and treated as the poor cousin to video?

The obvious answer is film and videomakers aren't always using their ears. If you can listen to what you are recording through a good set of headphones, which offer some isolation from background noise, you will hear the thinness of peoples' voices because the mic is too far away, or the noise of the television drowning out dialogue or your fingers thumping off the microphone as you fiddle with the controls.

You can blame camcorder manufacturers for supplying poor microphones and crap sound inputs on all but the most high-end prosumer DV cameras, but there are also simple steps you can take to improve the sound you record.

A standard piece of advice given to new filmmakers, is to get at least another microphone other than the on-board mic supplied with your camera. The microphone that comes with most consumer and prosumer range of cameras are omni-directional mics, meaning that they record from all directions, which is fine for ambient sound like the singing of birds in the forest or hub-bub of a crowd, but not if you want to pick out more directional audio like somebody being interviewed beside a busy road. In this instance, unless the camera goes right up close, the interviewee is likely to be drowned out by traffic.

On-board omni mics also have a tendency, at least among lower-end cameras, to pick up the mechanical sounds of the camera running, like the zoom motor and even the sound of the cameraman's heavy-breathing in those quiet video moments.

What mic?

Choosing a microphone depends on the situation you are using it for. A lapel or lavalier mic (starting from around £30 for the bargain-basement Hama LM09 to much more) is good for interviews and one-on-ones. These are typically omni-directional, but give a real sense of being up close and intimate with the subject. A purist like Dave reckons that cheaper ones can cut out too much of the ambient sound and "air" creating more claustrophobic results. They also are sensitive to wind noise and the rustle of clothing if not clipped on well to the subject.

Another option is a dynamic (no batteries required) handheld reporter's mic made by the likes of Electrovoice which is good again for interview work, although the mic will usually be in shot. You could use this in combination with a MiniDisc recorder to capture the audio of a speech at close range while setting up the camera at the back of a room for a long shot. These mics are around £100-plus and durable ("they last for years"). Dave reckons they're an essential component of your sound kit, for back-up if nothing else, although avoid buying a rock 'n' roll mike, like the Shure SM58, for this kind of interview work, he warns.

Dave likes gun mics, the signature of documentary-maker Nick Broomfield. These offer much more directional control, picking up sound in a cone-area of about 50 degrees in front of the camera. This is excellent for an interview where you are dealing with background noise that you can't get rid of (like traffic) or recording sound effects. Bear in mind that you will need a foam or furry windshield to protect the mic from handling and wind noise.

Since good sound invariably relies on you getting up close, you should also consider using a boom, especially if you plan on covering group interviews or action scenes. There is more to handling a boom than just having strong arms to hold your mic on a pole for long periods. The boom-handler has to be able to roll the boom toward the action without creating handling noise, be careful not to cast shadows or get the mic in shot and must be in synch with the cameraman as he changes shots. Headphones with a long extension are essential for manoeuvrability.

The final option is wireless mic, which consists of usually a lapel mic and match box size transmitter and a receiver that goes on the camera hot shoe. These are allow you to put some distance between yourself and the subject. You could use it for that speech I was talking about, or fly-on-the-wall reportage where the subjects often forget they are miked up it's so unobtrusive.

I should say I've had mixed results with these: the first time I used a pro mic I found it hissed and squelched so much the audio was unusable. It may have been a low battery problem - these things need a steady supply of juice. I've also used cheaper Azden wireless mics which were great in controlled environments, but not so good in a busy city environment where the receiver started picking up messages from passing taxi drivers using the same frequency. If I can, I prefer other to use other solutions to wireless mics. "Wireless is not as natural sounding - you have to work harder," adds Dave.

Working with a soundman

By now you are probably realising that if you are just a one-man band then it's going to be harder to get great sound. It's not unknown for camera people to handle both a boom and a camera, but it's tough trying to do two things at the same time.

If you've only got one chance to get that footage then it's safer to work with another pair of ears and hands. A good soundperson will be concentrating on not only getting a clean audio take with every shot, but will also be aware of acoustics, ambient sound, interference (like a plane flying over) and recording sound effects that the cameraman might miss.

Another consideration is what do you record to - camera or a separate recording device like DAT or, if you are on a budget, the Sony MiniDisc recorder? The recordings on the MiniDisc are slightly under 16-bit, so there is a small quality pay-off compared to the digital stereo sound of DAT or new cameras.

Recording sound on a separate audio recorder gives you more control at the recording stage of the process. "A separate recording system is almost always better than a camera. Because in a camera the video heads are close to the sound heads the specs are never as good in the real world as they are on paper, although they are good enough as they're used every day," says Dave.

Filmmakers who have their own DV editing system then synch the audio and video at the editing process.

"Hard drive space has just become so affordable that some people are just tending to digitise everything and then picking up what they need," says Dave, citing a recent DV travel documentary where the filmmakers used MiniDisc extensively to capture sound after the method worked well on a previous assignment.

You will probably be editing with at least two layers of audio - one ambient and one for dialogue - and possibly adding other audio tracks for sound effects or music. The cleaner the audio, the better for mixing, whatever the source of the recording is.

"Kids' Plugs"

One of the big drawbacks with many consumer and even prosumer cameras is they lack balanced audio connectors. They use a 3.5mm stereo jack input while pro microphones typically require more sturdy 3-pin XLR inputs.

The solution? Either you get an expensive camera like the Sony PD170 that includes XLR audio inputs or you invest a couple of hundred pounds or so in an audio adaptor from a company like BeachTek. You could get handy with a soldering iron and change the plugs on the mics yourself, but not only are mini-jack plugs unbalanced, but the plugs deteriorate and connections loosen more easily with use.

"These 'kids plugs' are a real liability, especially if you are going to be using them day in and day out," says Dave.

BeachTek's line of adaptors are attached to the tripod mount underneath your camera (see image at beginning of the page) and once you've hooked one up to the mini-plug input in your camera it takes over as the audio interface.

With a balanced input you can run a longer length of cable with less noise on the line either from your camera or even MiniDisc. The channels on the BeachTek can also supply phantom power, an industry standard 48-volt power supply, to condenser microphones which require an external power source.

"A BeachTek will have a much longer life than a camera will. In fact the good news with sound equipment in general is that you are good for ten or fifteen years. It wont easily become obsolete," says Dave.

Conclusion

If you got to this stage in the article then you are probably pretty serious about getting the sound right. Finding the right microphone for the right situation is going to be most important, which may also require getting an audio adapter and even colloborating with a sound person. "Don't try and find the magic bullet that does everything. People get very upset when the machine doesn't work the way they want it to..." says Dave.

He also recommends testing your equipment in the field as much as possible before and after buying. "People that are successful do tests." Can't argue with that.

David Hechenberger works for Location Sound in Vancouver, Canada. Its web site offers product reviews at www.locationsound.ca.

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