The location you pick will greatly impact the audio fidelity of the sound you record. When shooting interviews it’s important to consider what kind of soundscape you are in. Are there noisy birds tending to a nest just outside the window? Are you near a busy road or helipad? Best to move the interview to a spot that’s a bit quieter.
However you slice it, at the end of the day (without shooting inside some sound proofed bubble or something) you will be around noises. The important thing is to minimize their impact on your production.
When choosing a location to shoot in (or doing anything really) you have two options; indoor and outdoor. Both offer their relative pros and cons so it’s important to weigh up what your production really needs. Obviously for videographers, exterior locations provide much nicer lighting and in general, more picturesque scenery than indoors. This is all very well for the visual side of your team but if it’s your job to control the audio side of a project, exterior interviews might not be your best bet.
By their very nature, outside locations are outside and located much nearer to big noisy things that will disrupt your shoot. Cars are outside, roads are outside, planes are outside, animals are outside but most importantly, and wind is outside. The wind noise on your microphone might be enough in and of itself to reduce your beautifully shot interview into a crackling, whooshing mess.
Shooting inside is going to provide at best less problems and at worst, different problems. Inside noises can usually be reduced more effectively than ones that occur outside. A noisy air conditioning vent can (and must) be switched off. So to with refrigerators and any other humming devices that might be emitting sound. Your brain will filter these out when you’re on location (clever thing) but when you’re back in the editing room, the startling whir of a fridge kicking in will potentially ruin all your hard work. When working indoors, keep windows shut and turn off all electronic devices (producers can switch their phone’s to vibrate if necessary!) and remember when you leave the set, to turn back on any thing you turned off or you might get a call from a disgruntled interviewee with some curdled milk and off-chicken.
We recently ran a series of interviews for the project ‘When Does the Light Turn On?’. We ran the interviews inside, in quite a controlled environment, but unfortunately the whole building was on centrally controlled air conditioning. This meant we couldn’t turn off the air conditioning hum. This was another one of those moments where we had to just shrug and keep going, but it caused us untold grief in the edit room. We tried a couple of different techniques to minimize the hum, but the end were mostly forced to just cover it up with the score(music for the movie).
One last thing, don’t have any music playing when you’re shooting. It might seem like you’ll save yourself some time later by recording the soundtrack now, as you go, but this is inevitably going to become your worst nightmare. Editing takes a whole bunch of clips and puts them together in an order that may or may not necessarily reflect the actual order of events. That Christina Aguilera track you had in the background? It’s now an unintelligible messy footprint of sound that you simply cannot remove from your production. So be careful. You’ve been warned.
Once you’ve chosen you’re location and you’re happy with the bed of sounds (or lack there of) that it provides you with, it’s time to setup your equipment and do some testing. Set up your microphones the way you will use them for the interview and have your interviewee speak a few words, hopefully near or at the relative ‘standard’ volume they will use during the interview. Check the volume indicator on your microphone or camera’s readout. You want to make sure the volume never ‘peaks’. ‘Peaking’ occurs when the volume of a sound is too loud and causes distortion. A good signal for dialogue will hit around -12db to -6db.
Check the volume of your subject relative to ‘peaking’ (which occurs at 0dB) and adjust the input volume accordingly. Some microphones will have what is known as Auto Gain Control (AGC). This automatically boosts and ducks the input volume as it happens so as to avoid peaking, and so that quiet passages are audible. The problem with AGC is that it can be unpredictable and unceremonious in its approach, volume will radically dip and spike as your subject takes a pause or a breath, and background atmosphere levels will swell and whoosh unnaturally. If you are really, really scared about leveling issues then use AGC but really you shouldn’t need to and a little bit of setup and testing will ensure your interview subject’s voice will always be audible and will never peak. Not all AGC’s are built equally, so if you do choose to use it, find out if the hardware you are using, be it a camera, field recorder or external mic, has quality AGC. If it doesn’t, then its most likely not worth trying to use it, as some AGC’s have a tendency to really ruin sound.
Some microphones will also offer a hi-cut or a lo-cut. These are simply filters that the microphone applies to either cut out high or low frequencies. These might be good to play around with in environments where low humming or high buzzing can’t be directly controlled (by turning something off or closing a window) but make sure you don’t have them drastically cut into the vocal frequency of your subject.