Answers to some common questions about the built-in mike.
Depending on how you look at it, your camcorders built-in mike is either a great convenience or the ultimate compromise. On the plus side, the built-in mike is always properly plugged into your camcorder, it has no batteries of its own to run out of juice and it doesnt take up extra room in your camcorder bag. Negatives? The built-in mike doesnt sound all that great most of the time, you cant swap it out for a better design and its never any closer to your subject than your camcorder is.
In the next few pages, well answer some common questions about built-in microphones. If youve got a burning question that you dont see answered here, mail it to us (or email to firstname.lastname@example.org)–well address it in a future "Tech Talk" column.
Im really unhappy with the sound of my camcorders built-in mike. Is there any way to modify or replace it for better sound?
Unfortunately, theres no simple way to improve the sound of a camcorders built-in mike by changing the hardware. Most camcorders integrate the microphone into the case itself, making it virtually impossible to access the mike element without completely disassembling the camcorder. Even if you could tear into the camcorder, you still face several problems. First off, what would you replace the existing mike element with? If you had a different mike element to put in, theres an extremely good chance it wouldnt fit, or couldnt be mounted to the chassis, or wouldnt have the right type of wiring or wouldnt sound better after all…
Ive heard that Im stuck with my camcorders built-in mike. How do I get the best possible sound from it?
First off, lets pinpoint where most built-in mikes fall short. Though it may come as a surprise to many, the main limitation to the quality of a built-in mikes sound is not the mike itself. Its quite possible that a $200 condenser mike mounted atop your camcorder would give you little improvement in sound quality over your built-in mike.
How can this be? Simple–the real culprit behind the washed-out sound of a built-in mike is too great a distance between the mike and your subject(s). The cardinal rule of good sound is to get the mike as close as possible to the sound source. In the world of all-in-one camcorders, however, the best distance to capture images is rarely the best distance to record sound. Few videographers set up their shots based on what theyre hearing in their headphones. Instead, we usually get the best visuals we can and leave the mike to fend for itself.
To get the best possible sound from your built-in mike, try favoring your mike instead of your lens. Experiment with getting closer to your subject, shooting things at wider zoom settings. If you dont need to be 40 feet from your subject, move in. Not only will this give you more crisp, up-close sound, but youll enjoy steadier handheld images to boot.
Why does my built-in mike seem to pick up every little gust of wind, and what can I do about it?
Designing an effective wind filter into a mike requires a fair amount of room for foam or other wind-absorbing materials. Few camcorders have the space for such a luxury, so most built-in mikes get wrapped in little more than a thin layer of foam. Any wind above a light puff goes right on through, where it can then manhandle your camcorders mike diaphragm.
As an after-the-fact "solution," many camcorders include a wind-filter switch. This filter simply throws away your bass frequencies (where we hear wind noise the most), leaving your audio with a thin, tinny sound. Unless you like your audio to sound like its coming through a cheap transistor radio, this is no solution at all.
The best way to avoid wind noise is to avoid wind. Try to shoot as little as possible on really windy days. If you cant avoid windy conditions, try to position yourself behind the shelter of trees or buildings. If you must shoot in high winds, rotate your camcorder until you find an angle where the wind noise is least severe. For some camcorders, this will be where the wind is blowing across the mike instead of directly into it.
If your built-in mike sits atop the camcorder, you may be able to wrap the mike assembly in a blanket of light, open-cell foam. On all-in-one models, some folks have had good results taping a layer of foam over the mike. Attached with black electrical tape, a small piece of charcoal gray foam may be nearly invisible on your camcorder.
Its easy to tell if a piece of open-cell foam will work for wind protection without muffling your recordings. First, hold the foam a few inches from your mouth and blow through it. If you can feel breath on the other side, the foam is too porous. Next, put the foam right up to your lips and blow again. If it offers a lot of resistance, the foam may be too dense. Finally, cover one ear with the foam and listen through it. If you can hear a noticeable dulling of sound (your own voice, for example), the foam will have the same effect on your recordings.
My camcorders built-in zoom mike sounds really strange as Im zooming. Why is this?
You can think of most camcorder "zoom" mikes as two mikes in one. One mike is stereo, pointing out to the left and right sides of your camcorder. The other is a directional mono mike, which points straight ahead. As you zoom, the camcorder adjust the balance between these two mikes. Zoom in tight, and the camcorder progressively turns down the stereo mike. Zoom out, and the balance shifts away from the mono mike until all youre hearing is the stereo mike.
Frankly, this sounds strange because it is strange–theres no natural precedent for this stereo (two ears) to mono (one ear) transition. Our eyes have grown used to the similarly unnatural visual zoom; our ears are still caught off-guard by an "aural" zoom. For this reason, many folks find the zoom mike to be a gimmick that ransacks the continuity and realism of recorded sound.
To make matters worse, theres really no such thing as a "zoom" mike. No microphone–not even the best shotgun mike–can approach the selectivity of the camcorders zoom lens. For more on the difference between directional mikes, see last months feature “The External Mike.”
If you can disable your camcorders zoom mike, try shooting in the "wide" position only. This will give you spacious stereo sound regardless of your lens zoom setting. If you cant shut off your zoom feature (or prefer not to), try to zoom only between shots. This will improve the look as well as the sound of your videos.
Why does my camcorders mike pick up more and more room noise when my subject stops speaking?
This is not so much a problem with your camcorders mike as it is with its record electronics. Most camcorders have an auto gain control (AGC) circuit, which tries to put a strong audio signal on tape at all times. When someone is speaking, the circuit adjusts the record level for that sound. When it hears "silence," the circuit keeps increasing its sensitivity until background noises become a dull roar.
If you can set your record levels manually, this is the best solution. Manual record levels disable the AGC, preserving the difference between sound and silence. Unfortunately, theres no simple solution apart from using manual record level controls, and most consumer camcorders do not have these. As a last resort, you can always run your sound through an audio mixer as you edit, compensating for the action of the AGC circuit with the mixers fader.
My camcorders built-in mike picks up lots of noises from its own motors and buttons. What can I do to eliminate these sounds?
This problem is closely tied in with the previous question. As your camcorders AGC struggles to put something on tape, it often begins picking up zoom- or focus-motor noises, transport noises or the click of fingers on buttons. Apart from disabling the AGC, there are a few tricks you can use to compensate.
For starters, try using manual focus. Even if youre shooting a stationary subject from a set distance, most autofocus systems continually make fine adjustments to the image. This creates unwanted noise, unnecessary wear on the motors and needless draining of the battery. Likewise, if you can avoid zooming during quiet sections, youll get less motor noise on tape. Lastly, try to refrain from pushing buttons on your camcorder until theres an appreciable amount of sound for the mike to pick up.
Putting your camcorder on a tripod–and not touching it–will also go a long way toward eliminating unwanted noises.