Sound

Once you start getting serious about video, then issues relating to sound start raising their heads. This page attempts to address some of these issues.

Before we get into the nitty-gritty, though, there's a few things we should look into so that we're all starting on a level playing field of understanding and knowledge.

Types of Sound

Essentially there are four types of sound, subject sound, ambient sound, background sound (e.g. music) and commentary.

Subject Sound is that which you you want to to hear in your video.
Ambient Sound is the sounds that your camcorder's microphone picks up that you would prefer not to hear on your video. The most obvious example of ambient sound is wind noise. Another is motor noise that is sometimes recorded when shooting in very quiet conditions; this sort of sound is caused by the camcorder's automatic audio gain control circuits that attempt to boost whatever sounds that your mic picks up to give a recordable level on your tape's sound-track. Some camcorders are more prone to picking up motor noise than others - Canon camcorders have a reputation of picking up motor noise.
Background Sound is something that you add at the editing stage. Usually music, you can easily add this when editing by either deleting the portions of the audio layer (track) and replacing with your music, or by adding an extra layer (track) to hold our background sound. One of the major problems that folk have is getting hold of suitable copyright-free music - but we'll cover this later.
Commentary sounds (pun!) an easy thing to add - but once you start using commentary you may encounter problems - again we'll address this and offer a solution later.

Layers

One of the features that the beginning video editor fails to use is that of layers. We tend to capture our video, and accept the automatically created layers when we tranfer our edited clips to the timeline (sometimes called the "track-line"). Don't be afraid to add layers and to use them. For example, you can add a layer and use it to add background music. You can add a layer for any commentary you might like to add. If you're into gizmo "wow" effects, you can add whoosh sounds to coincide with your transitiions - though personally I don't like that sort of thing.

The more you use layers though, the more you have to think ahead as to what you intend doing.

Microphones

Once you start getting serious about sound, the first thing you'll start to consider is an alternative to your camcorder's built-in microphone. If you failed to put "external microphone socket" on your "must-have" list when you bought your camcorder - then I'm afraid you'll have to skip this section.

Before I start running through the microphones that I've accumulated for various purposes, just a quck word about stereo. Stereo microphones are very expensive, and if (like me) you don't have bottomless pockets you might consider that you can make do with mono microphones. I certainly don't seem to have had a problem by using mono mics. All you do have to have, though, is a short lead or adapter converting the mono output from your microphone to the stereo jack to go into your camcorder.

The directionality of microphones is of interest to people recording video. There are essentially four types of microhone indicated by the pick-up pattern (directionality) of the microphone, omni-directional, cardiod, super-cardiod and shotsgun. Omni-directional pick up sound equally in all directions, and the pick-up patterns for the other three are illustrated below (shown to scale to indicate pick-up range), from left to right, cardiod, super-cardiod and shotgun.

General-Purpose/Directional Microphone

This is the one I'd suggest as being the first one to buy. Maplin do a "Super Electret Condesor Video Zoom" microphone with a switch to change the pick-up pattern from normal (much like your camcorder's mic) to a reasonablly directional pick-up pattern. This microphone gives a combination (switchable) of cardiod and super-cardiod. Sound quality is acceptable, but isn't the greatest in the world - but if you want that, it's going to cost you several hundreds of pounds. The Maplin one (part number BV57M) can be bought from here for about £25, and comes complete with a windshield, two extension leads and an attachment that permits it to be either fitted in your camcorder's hot-shoe or alternatively on a tripod. With as suitable bolt (same size as your camcorder's tripod mount) and pole, you can even use it as a home-made boom microphone. You'll also
need batteries - part number QN68 for a pack of 6 at £4.99 available here. Click on
picture for a larger image.

Tie-Clip Microphone

This little mic is useful for commentaries. Just run the lead from the mic clipped to your jacket or shirt to your camcorder and use your camcorder's remote control to record that commentary. Available from Maplins again, part number LB69A and can be obtained from here for £20. Again, you'll need batteries, part number QN68 for a pack of 6 at £4.99 from here.

Boundary Microphone

This is the one for recording meetings where everyone is sitting around the table. It's classed as omni-directional. The one suggested here has a switch to change the pick-up pattern from omni-directional (all round) to forward-facing (but very broad). You simply plonk it in the centre of the table and you'll pick up what everyone is saying. This one (part number 952.194) is available here at £23. Again, you'll need batteries, part number QN68 for a pack of 6 at £4.99 from here.

Shot-Gun Microphone

I'm cheating a little here, because I can't give a source to purchase this microphone.
I bought it for my analogue video camcorder several years ago (it was very inexpensive) before the days of digital video. If anyone knows where one of these can now be obtained please e-mail me so that I can include a link here.

The type number is ECM-1035, and it is highly directional. Mounted on the camcorder's hot-shoe it projects forward of the lens, so I have to be careful to use the camcorder with zoom to prevent the microphone from appearing in-shot. This one is an electret type and uses a single AA battery. Click on picture for a larger image.

Wireless Microphones

Once you start taking your video-making seriously, one thing that you'll probably want is a wireless microphone. I saw some cheapies for sale on the market in Mold for a tenner and I tried one. It was a complete waste of money. Noisy, poor signal level and it constantly drifting off tune.

After a couple of months of frustration, and with a "talking head" project about to be started I found a relatively inexpensive solution which has worked out very well. I bought a karioke wireless microphone from Argos for £50. Unfortunately, the receiver for this is mains-powered (or more accurately powered by a mains adaptor) - which for video work is not very statisfactory - I wanted something that could be used anywhere. Being an inveterate "Mr Fixit" I was able to convert the receiver to use rechargable internal batteries. For those who would like to follow my example, you'll find below sufficient information for anyone who's able to wield a soldering iron.

You'll need three PP9 rechargable batteries (Maplin had a deal of three for about £12). To connect the batteries you'll also need three clip-terminals with pigtails to attach the batteries - these are available from Maplins or Tandy's. You'll also need a few inches of foam to stop the batteries rattling about inside the case. You'll obviously need a soldering iron.

Then. when you've got all your bits together:

Open the receiver case by undoing the four screws on the underside and prise the lid off (you'll have to turn the aerials to the vertical position to clear the lid).
Identify the socket where the mains adaptor plugs in, and solder two wires preferably colour-coded), positive to the center and negative to the side. Take the three PP9 battery terminal connector pigtails and strip the ends off, then twist all four positives (including the wires from the adaptor input) together, solder and tape off to insulate.
Clip in the three batteries, and locate two on one side on one on the other
(they'll only fit one way round).
Lay foam on top of the batteries, and gently refilt the case lid, replacing the four screws.
Leaving the ON/OFF switch in the OFF position, charge the batteries for five hours using the mains adaptor. Subsequently you only need to recharge for three hours.

The last thing that you'll have to do is to make up a suitable audio lead to connect the 6.4mm mono socket on the receiver to your camcorder's mic-in socket.

The system works very well - the quality is better than that obtained under the best conditions with the camcorder's internal microphone. You'll get about four hours continuous operation of the receiver on one full charge - enough for most circumstances. The microphone transmitter uses a PP9 battery, so you might like to consider getting yourself an extran rechargable PP9 with a suitable battery charger (many "univeral" chargers allow you to charge PP9s).

Accessories

One of the most useful accessories I've got for
sound is a little Sharp MD MT-280S Mini-Disk (MD) recorder/player (dry battery). I also have a more expensive recorder/player, the Sharp MT877 which is rechargable. Their important characterisics are that the recorded sound will be in sync with the video (and on-camcorder mic's sound), so that the sound can easily
be dubbed in with my video editor. Not only are these recorders extremely useful for video sound, they will double as a neat recreational Walkman giving me up to 5 hours play time on a single mini-disk.

Planning a Movie For Sound

It's impossible to give guidance for all movie shooting situations, but to give some ideas I'm going to outline a scenario for producing a documentary, with special focus on sound. What we're going to do is to produce a movie with a "talking head" commentary with cut-aways to shots, keeping the commentary going through the cut-aways. Professionals would use two or more video cameras for this sort of shoot, but us amateurs have to improvise.

The first thing to do is to shoot all the cut-aways, and edit them to length so that we can get the timings. Then we have to make a note of all the clip timings in the order in which they're going to appear in the movie, making provision for any "talk" between cut-aways. While we're doing this in our video editor we'll remove the audio track so that we have only video, each cut-away saved as a DV AVI file.

The next thing is to set up camcorder and microphone in a relatively quiet environment and start shooting the "talking head" movie, commentary and all. This usually has to be done in sections because you'll never remember the timings for the whole movie. Ideally you'll "talk-through" the timings for the cut-away clips that you'll be putting in.

The next thing to do is to use our video editor to capture the whole commentary, stitching together the sections that you've taken.

Lastly we replace the commentary video sections (leaving the audio) with our cut-away video shots (which have no audio). We can most easily do this in a separate layer in our time-line and nudge each cut-away clip back and forth to sync with our commentary. Previewing it at this time will superimpose the two video tracks (depending on our editor). With some video editors it may be necessary to put the cut-away clip layer above our commentary track.

Once everything is in place, we can cut-out the commentary video at the appropriated places and insert the relevant cut-away clips in place of the video we've removed.

Obviously, we'll preview the whole thing, add any titling/credits and transitions before saving, then making the video to whaterver medium that we're using.

The result is a professional-looking (and sounding) video with good continuity "talk-through" all our cut-away clips, with the "talking-head" commentary blending through the whole movie while remaining in sync.

In any quiet parts of the movie we could have added some background music, fading in and fading out so it's smooth. This is best added in an additional layer.

Background Music

Some video editor like Vegas 4 provide good sound editing facilites, but others don't. If your video editor's sound editing isn't good then you may have to get your self a sound editor like Goldwave or Sonic Foundry.

To get seamless music you really need to be using loops. These are music fragments that can be copied and pasted (CTRL/C and CTRL/V) to butted together so that the music track is seamless. With most video editors, providing you assemble your loops in a separate timeline layer you should be able to do this without any trouble. You can speed things up by adding (say) four loop sections, then selecting the four and copy-and-pasting those end-to-end. Just keep repeating to the lenght that you want.

You can pick up a selection of loops from here (9Mb).