14 Sound balance and location acoustics

Sound balance

At each location, you'll be faced with human voices which you want record intelligibly, plus other sounds relevant to the location itself. These form an aural background, and you need to obtain a balance between the two. Otherwise, if you eliminate the background sound altogether (perhaps using extremely close mic technique) the result will probably sound much as if it had been recorded in a studio, whilst the pictures tell a different story.

Ah, the magic of television. Whilst the main concern when dealing with contributors is to record intelligible sound, you also want to match the sound to the pictures. For example, if you interview someone in an open-plan office, you expect to hear phones, conversation, computers, copiers, air conditioning, etc. in the background. The secret is to establish a believable balance between the speech and the background noise.

Moreover, the pictures often assist you when you have extraneous noise, because as long as the source of the noise appears in shot, e.g. traffic when standing at the roadside, then the viewer can tolerate/accept a fair amount of the noise. This is the reason why most television sound – although of high quality in itself – is unacceptable as radio sound (in which you expect a lower background level), since the sound in each medium is doing a different job.

Open-plan office example

However, you still have to judge the level of background sound that's acceptable/desirable. Let's go back to the open-plan office, and listen to the gun mic (on cans, of course). Angle the mic in different directions, and listen to the changing level and quality of the background sound.

If there are conversations, phone calls, etc. they must be kept below the level of intelligibility if you're concentrating on a contributor speaking in front of the camera. In this instance, you must beware of sounds becoming confusing to the listener, as opposed to positively contributing to the aural experience. Once words become distinguishable, the ear/brain will attempt to incorporate them into a coherent whole, and following two unconnected conversations at once is next to impossible with both ears, and completely incomprehensible with one mono mic!

Air conditioning, computer fans, photocopiers, water coolers, etc. all need to be kept to a constant minimum. It may not be necessary to completely lose these noises, providing you are confident they won't suddenly change in level. (Phones ringing in the background will only prove a menace if your recording needs to be edited at that point, see Section 15, Recording for the edit; Wildtrack).

This is the secret of using mics, listen to their output and move them around to find the best position to obtain the sound you want. The omni mic lets you balance the sound by varying its proximity to the contributor. The gun mic not only enables you to control the balance of intelligible sound to background noise by its proximity, but also its angle and position help you minimize unwanted noise. It is for you to judge which mic suits your needs, and that of accurately portraying the ambience of the location behind the dialogue.

Location acoustics

Rooms with hard surfaces (e.g. tiled walls, windows) and/or high ceilings usually suffer from over-reverberant sound (especially indoor swimming pools and tiled shower areas in changing rooms, which frequently produce severe echo), possibly making speech indistinct. Using a gun mic may not always lessen the pick-up of unwanted sound, since sounds apparently off-mic may be reflected straight back into the capsule, depending on its position relative to the reflective surface. You can adjust its angle to minimize the effect, but if you're forced to record in this type of location (and beware the spacious boardroom) you'll almost certainly need to use close mic techniques, probably necessitating the use of a clip mics. However, if the shot shows the room size, allow some of the ‘spaciousness’ into the soundtrack.

As already mentioned (Section 2, Sound measurement; Acoustics), soft furnishings, carpets, curtains, even shelves of books, can all help to deaden the acoustics, and these surroundings are more frequently preferred as a setting for location recording.

Voice-over

You may be asked to provide voice-over narration from a presenter/reporter on location, and for this you won't want any hint of location acoustic. Depending on the ‘quality’ of their voice, a gun mic working relatively close to their mouth is the preferred option, or the stick mic (probably working even closer) if the gun proves unsatisfactory. To help acoustic isolation I've even wrapped curtains, rugs or bedclothes around narrators to achieve the desired result (just so long as they're not claustrophobic!). Listen carefully to ensure they don't rustle their script, and suggest they re-write it if necessary to avoid turning a page (and yes, they may need to use a torch when wrapped in curtains, etc. and you know who they expect to provide one!).