Wednesday, July 18, 2012

A bit of Sound Advice (on location)

For the last 8 months I've been working on a documentary doing camera, sound and I've even been doing the interviews the last few occasions. It's a bit much for one person but considering the budget and the advantages of being one-on-one with your subject, bringing in a soundperson has not been an option.
But obviously there is a compromise in sound quality when you're working without a dedicated soundperson. One of the biggest challenges is the placement of the microphone, in my case a wireless Sennheiser mic (MKE-2). Either it is visible and distracting on a person's chest or hidden behind clothing with the risk of the microphone rubbing against garment, thereby creating unwanted noise.
The people from Location Sound Corp have written a nice piece on lavalier microphones and the problems you may run into. They also have a few very good tricks to fix some of these problems:

One of the ever-present difficulties of hiding lavaliers under wardrobe is clothing noise. In actuality, there are two different causes of "clothing noise": contact noise and acoustic noise.
Contact noise is the result of garments rubbing against either the mic capsule itself or the leading few inches of cable (equally sensitive to friction). Contact noise can usually be controlled - if not completely eliminated - by careful positioning and taping down of the mic and cable.
Begin by securing the clothing on both sides of the mic capsule. This can be done by sandwiching the mic between two sticky triangles of cloth, camera, or gaffers tape. Form these triangles by folding a few inches of 1" wide tape corner over corner, similar to folding a flag.


By immobilizing the mic between both layers of clothing, you have eliminated the possibility of either layer of clothing rubbing against or flapping onto the microphone.
If the lavalier must be positioned between skin and clothing, or attached directly to the skin, then a professional medical/surgical tape should be used against the skin.
Once the mic capsule has been secured, the next step is to form a strain relief for the thin cable. Make a small loop just under the mic capsule. In the case of very sensitive mics, such as the Sony ECM-77, the Sennheiser MKE 2, and the Sanken COS-11, make the loop go around twice. Tie a small thread or use a thin strip of camera tape (sticky side out) to preserve the loop. Tie the loop loose enough so that it can "breathe" (change diameter to absorb tugs).

Apply a few inches of tape along the cable below the loop. Any tension on the cable will be absorbed by the garment, rather than by the microphone (which is somewhat isolated by the floating loop).
The remainder of the mic cable can be run under clothing and can terminate either at the waist or the ankle. The end of the mic connector should be secured so that it does not dangle freely.
During a take, it becomes a simple matter to plug in an extension XLR cable. Afterwards, the talent can easily be disconnected so that he or she is free to roam around.
When using an external tie clip, it is still important to think in terms of creating a strain relief. Loop the thin cable up and under the tie clip, forming a semi-circle, and passing through the wide hinge of the clip. Continue the loop behind the garment, and bring the cable around downward, thus completing the circle. As the cable loops downward, it should be inserted between the jaws of the tie clip and the back of the garment. Hide the balance of the cable behind the wardrobe.


Not only is this arrangement more pleasing to the eye than a dangling cable, but also the floating loop of the cable isolates the mic while the grip of the tie clip serves as a strain relief.
Acoustic clothing noise is the sound generated by the clothing itself as garments or layers rub against each other when the actor moves. Noise is much more prevalent from synthetic fabrics than from natural cottons or wools. There is no simple remedy, only prevention, so it is wise to consult early with the wardrobe department.
However, here are a couple of tricks that may help. Anti-static sprays, such as Static Guard™, will reduce static electric discharge, clinging, and reduce friction. Dry silicon spray lubricants sometimes help, but be careful of staining. Stiff or starched clothing can be softened with water or alcohol (make sure the colors don't bleed). Saddle soap, silicon, or light oil can take the bite out of hard leather.
Another noise problem common to lavaliers is that of wind noise. Manufacturers usually supply small foam or metal mesh windscreens with their lavaliers, but these are usually more effective against breath pops than against outdoor gusts of wind.
Lavaliers used under clothing have the advantage of being partially shielded from the wind, but may still require added protection.
Clothing rubbing against windscreens can be extremely noisy, so great care must be taken when using hidden lavaliers out of doors. Surrounding the windscreen with sticky tape and securing it to both layers of clothing, as you would a bare mic, will reduce the friction noise. However, the tape may destroy a foam windscreen when it is removed! Inexpensive, expendable windscreens can be made by wrapping the mic in acoustafoam, or by pulling the foam booties off of video cleaning swabs.
Cheesecloth over a mic works very well against wind. Another Hollywood variation is to snip the finger tips off children's woolen gloves, and pull the wool tips over a lavalier wrapped in foam or cheesecloth. Or you can get lavalier windjammers for high wind applications.

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