by Stephen Lorne | http://www.stephenlorne.com
This article is geared specifically for the rookie filmmakers, with concepts and tips written with the assumption that they are about to make their first short film, and are looking for low or no-cost ways to get usable sound to tell the story. I make some gross generalizations, and only touch on some topics that people have spent lifetimes studying.
When you endeavour to make a short film with a micro budget (or none at all), you are taking on some interesting challenges. Every aspect of your production is a series of compromises, and the sound department is no different. Your biggest challenges will be:
accessing decent quality sound gear;
obtaining the services of a location sound person who has any experience;
Getting quality audio is a complicated mix of factors, but there is a general order of importance for quality of dialogue audio:
proximity of microphone to the actor
microphone type selection
quality of recording device
As much as I love talking about gear and lav techniques and battery distribution systems, the biggest factor in determining the quality of sound is something you have control over, long before you've lined up your recording device and someone to work the boom. That factor is location, and there is a truism about the relationship between it and sound: no gear or level of skill can save sound in a bad location.
To understand the problems with location (and the ways to mitigate those problems), you have to put yourself in the editor's seat. The editor will be tasked with telling the story with the footage they've been handed, and the sound will need to be as clear as possible to give options in post. They will be splicing together clips with 'L' and 'J' cuts and variations in background noises will critically hinder their options. Those background noises will fall into two general categories: constant, and intermittent.
Generally, intermittent noises (car horns, airplanes, etc) cannot be managed in post if those noises happen during dialogue. The issue isn't that you can hear the noise under dialogue, it is that the editor can't cut that dialogue with another take that DIDN'T have the noise. Strategies for dealing with a location that has uncontrollable intermittent noise sources:
volume of takes...the more takes, the greater chance the editor can find what they need within the pile, as they balance the quality of the acting and visuals with the quality of sound
establish the noise source...B-roll visual footage of the environment that is creating the sounds will allow the audience to quickly accept the situation (assuming it makes sense in the context of the story)
High-pass filter (also known as low-cut) on the recording device can mitigate low rumbling sounds (like trucks, wind, and even boom pole handling). Some mics have this option also.
Constant noises can be more problematic, to the point to destroying the dialogue altogether. The worst indoor offenders are climate systems (ie furnaces and AC) and refrigerators. Tips to deal with them:
When scouting a location, ask about control of the AC/furnace/furnace-fan. Of everything that can possibly effect sound quality, these are the most problematic because they occupy the same frequency spaces as dialogue (and are therefore very difficult to filter out in post). Seriously consider a different location if you don't have environmental controls in dialogue-heavy spaces.
A fridge has a temp dial inside...if you turn it down all the way, the fridge noise disappears without having to unplug it. Leave your car keys in the fridge, so you can't leave without turning it back on.
Room tone. Recording 20-30 seconds of room tone for each setup will allow the editor to smooth over transitions between shots, as well as give any noise-reduction plug-ins a chance to properly identify the problematic sound. Room tone is most effective with everyone in the room (as it was shot), and should be done every time the background noise changes.
As a last resort, sound blankets (used moving blankets) thrown over offending appliances can help muffle the problem.
Proximity of microphone to the actor
A good boom operator will take risks and ride the line at the top of the camera frame, knowing that every inch counts. If the microphone is in the correct position, you can get good sound out of very mediocre gear. The best results come from a mic boomed from above, pointing at a space about 3 inches outwards from the actors mouth (from above, because in most locations unwanted sound sources usually come from above, not below). This proximity will also help mitigate unwanted room echo (more on this later). Strategies to get the mic as close as possible:
Allow the boom op to take part in the blocking rehearsal, so they get an idea of the camera movement.
Don't berate the boom op for dipping the tip of the mic into frame (assuming the problem isn't chronic). A discouraged boom op will play it overly safe in critical scenes, and you'll never know that the sound quality suffered until your hear it in post. Proximity is so critical, that the occasional boom dip into frame, while unwanted, is worth the risk. In post, an editor can punch in a bit for the offending frames, or cut away to a different angle. What cannot be improved in post is a microphone too far away from the actor. Informing the boom op that they are in frame is necessary, but be aware of pushing them too far into safety.
A mic on a boom pole above and close to the actor will always sound better than a mic on the camera.
Shoot with one camera. Using two cameras (usually a tight and a wide) may seem efficient for getting multiple angles in one take, but your sound quality will suffer. It greatly increases the safe distance for the microphone from the actor, and reduces the safe shadow spaces for the mic and boom pole. Productions with larger budget can mitigate this with high-end lav mics and transmitters.
Microphone type selection
In a no-budget production, you will often have to make-do with whatever equipment is available. A useful over-generalization is that there are two types of mics: outdoor shotgun mics, and shorter indoor mics.
The shotgun mics are often 12” long and are very directional (they pick up the dialogue well when they are pointed directly at the source). They are great for outdoor use, but their directional strength is often a problem indoors: they pick up 'reflections' (ie echo) as sound bounces off walls in anything but large spaces. This gives unwanted reverb in your sound, and audiences very much associate this with low-budget movies. The Rode NTG series are budget-friendly examples of this type of mic.
The indoor mics have less directionality, and less 'reach'. They need to be closer to the actor than with a shotgun mic, but are better at rejecting the room's reflections. They work well for dialogue because they don't need aggressive cueing (boom movement) between actors in the same scene. Budget-friendly examples of this are the Audio Technica AT4053b and the Rode NT5.
Very likely, your no-budget production will not have the luxury of having more than one microphone on hand. If your film has an even mix of indoor and outdoor dialogue, I would lean towards using the longer shotgun as the jack-of-all-trades IF the actors will be delivering conversation-level dialogue while inside. If there is alot of yelling, shouting, or loud delivery, the room echo will be obvious and unavoidable, and therefore I would suggest an indoor microphone.
Finally, mic selection may be dictated by your ability to power the mic. Unlike stage mics (dynamic), condenser mics require an external power source (called phantom power). Every budget recorder provides phantom power through the XLR input, back into the microphone. If you are recording directly to the camera, however, your DSLR likely has a 1/8” input, and this will not provide phantom power. In these situations, you'll need a microphone that takes batteries (such as the Rode NTG2), or a pre-amp interface between the mic and the camera.
In no-budget productions, often filmmakers will only have access to entry-level sound equipment. One of the compromises between budget and high-end gear is the self-noise that the electronics introduce to your recording. Everything in the sound chain introduces an amount of self-noise (referred to as a 'noise floor'), but cheaper gear introduces more. To mitigate this extra noise, you must gain stage your sound chain, with the aim to get the best 'sound to noise ratio' (sound=dialogue, noise=everything else). Too much sound, and you get distortion (the worst case scenario)...too much noise, and the dialogue will be distant and thin compared to everything else you hear.
Start with the first piece of gear at the sound source: the microphone...this is where getting close to the actor gets you the best sound-to-noise ratio. Next, the recording device. You'll want to record at a level that gets the best ratio, but leaves enough headroom so loud voices and sudden noises (such as a closing door) don't distort. A good target for normal dialogue is between -20dbfs and -12dbfs. 0dbfs is where distortion will occur. If the dialogue is recorded too low, the levels will have to be increased in post production, and the background/electronics noise will amplified. Simplified meters on some recorders and cameras will indicated this with green (safe), yellow (optimal), and red (distortion) meters. The idea is that, starting with the mic, each device in the chain is set to optimal levels, rather than using a gain knob down the chain trying make up for a previous device that isn't set to optimal levels.
Proper gain staging is more complicated when using lavalier mics and transmitters, since more electronics are being introduced into the chain (more on lavalier mics later).
Quality of recording device
Oddly, one of the most expensive items in the sound kit is often the least important item when it comes to sound quality on a no-budget set. Budget recorders, such as the Zoom H2n, H4n, H6n, and the Tascam DR-60 are rarely the difference in recorded sound quality compared to the other topics discussed in low-budget productions. They do make a difference in usability and practical application depending on the models (number of recording channels, limiters, portability, quality of dials, battery life etc). If the sound person familiarizes themselves and practices with the entry-level device being used in the production, then it will rarely make the difference between good and bad audio.
Thoughts on lavalier mics and radios
Most filmmakers have seen or used lav mics on either commercial shoots or films. In the right hands, with the right gear, they are very convenient and sometimes even efficient.
However, the truth is that for no/low budget scripted productions, the hassles and cost far outweigh the benefits. Anything less expensive than the Sennheiser G2/G3 units (bare minimal level units for professionals) are unreliable and deliver dubious quality, even in skilled hands. Applying hidden lav mics to actors requires experience and an often underestimated amount of supporting gear and supplies. Clothing scratch, frequency dropouts, wind, comfort levels of actors, are just some of the challenges that will occupy most of your sound mixer's time. Money or time spent on using lavs in a micro-budget shoot would almost always get better results if applied elsewhere.
Final quick tips for your novice sound person
Hold the boom pole gently. If cradled with the anchor hand between thumb and forefinger above the head, it can even be held with a single finger on the other hand.
Bring extra recording cards, extra batteries, an extra XLR cable.
Test the boom with the camera for the scene: put the mic tip in frame, then pull up until it disappears from the camera monitor. Find a distant visual reference...don't go below that line.
Arrive early, scout the space for sound problems.
Make notes with the script for any sound effects or dialogue that needs to be recorded off-camera (known as wildlines).
Mistakes are NORMAL. If you forgot to hit the record button, speak up, don't hide it.
Stephen Lorne is a sound mixer based in Ottawa. He has mixed for feature films, television, documentaries, commercials, and sporting events throughout Canada.
Find out more about Stephen on his website: http://www.stephenlorne.com